From 819da3b62e0f01683c470ba3830c230a4fdc64f9 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Mon, 3 Feb 2025 23:15:24 +0000
Subject: [PATCH 01/14] Convert change detection to a Python script

---
 .../workflows/reusable-change-detection.yml   | 149 ++++---------
 Tools/build/compute-changes.py                | 199 ++++++++++++++++++
 2 files changed, 242 insertions(+), 106 deletions(-)
 create mode 100644 Tools/build/compute-changes.py

diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index c08c0cb8873f12..5f43ead83617ee 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -52,122 +52,59 @@ jobs:
     timeout-minutes: 10
     outputs:
       config-hash: ${{ steps.config-hash.outputs.hash }}
-      run-cifuzz: ${{ steps.check.outputs.run-cifuzz }}
-      run-docs: ${{ steps.docs-changes.outputs.run-docs }}
-      run-hypothesis: ${{ steps.check.outputs.run-hypothesis }}
-      run-tests: ${{ steps.check.outputs.run-tests }}
-      run-win-msi: ${{ steps.win-msi-changes.outputs.run-win-msi }}
+      run-cifuzz: ${{ steps.changes.outputs.run-cifuzz }}
+      run-docs: ${{ steps.changes.outputs.run-docs }}
+      run-hypothesis: ${{ steps.changes.outputs.run-hypothesis }}
+      run-tests: ${{ steps.changes.outputs.run-tests }}
+      run-win-msi: ${{ steps.changes.outputs.run-win-msi }}
     steps:
+    - uses: actions/setup-python@v5
+      with:
+        python-version: "3"
+
     - run: >-
         echo '${{ github.event_name }}'
+
     - uses: actions/checkout@v4
       with:
         persist-credentials: false
-    - name: Check for source changes
-      id: check
+        ref: >-
+          ${{
+            github.event_name == 'pull_request'
+            && github.event.pull_request.head.sha
+            || ''
+          }}
+
+    # Adapted from https://github.com/actions/checkout/issues/520#issuecomment-1167205721
+    - name: Fetch commits to get branch diff
+      if: github.event_name == 'pull_request'
       run: |
-        if [ -z "$GITHUB_BASE_REF" ]; then
-          echo "run-tests=true" >> "$GITHUB_OUTPUT"
-        else
-          git fetch origin "$GITHUB_BASE_REF" --depth=1
-          # git diff "origin/$GITHUB_BASE_REF..." (3 dots) may be more
-          # reliable than git diff "origin/$GITHUB_BASE_REF.." (2 dots),
-          # but it requires to download more commits (this job uses
-          # "git fetch --depth=1").
-          #
-          # git diff "origin/$GITHUB_BASE_REF..." (3 dots) works with Git
-          # 2.26, but Git 2.28 is stricter and fails with "no merge base".
-          #
-          # git diff "origin/$GITHUB_BASE_REF.." (2 dots) should be enough on
-          # GitHub, since GitHub starts by merging origin/$GITHUB_BASE_REF
-          # into the PR branch anyway.
-          #
-          # https://github.com/python/core-workflow/issues/373
-          grep_ignore_args=(
-            # file extensions
-              -e '\.md$'
-              -e '\.rst$'
-            # top-level folders
-              -e '^Doc/'
-              -e '^Misc/'
-            # configuration files
-              -e '^\.github/CODEOWNERS$'
-              -e '^\.pre-commit-config\.yaml$'
-              -e '\.ruff\.toml$'
-              -e 'mypy\.ini$'
-          )
-          git diff --name-only "origin/$GITHUB_BASE_REF.."        \
-            | grep -qvE "${grep_ignore_args[@]}"                  \
-            && echo "run-tests=true" >> "$GITHUB_OUTPUT" || true
-        fi
+        set -eux
+
+        # Fetch enough history to find a common ancestor commit (aka merge-base):
+        git fetch origin "${refspec_pr}" --depth=$(( commits + 1 )) \
+          --no-tags --prune --no-recurse-submodules
+
+        # This should get the oldest commit in the local fetched history (which may not be the commit the PR branched from):
+        COMMON_ANCESTOR=$( git rev-list --first-parent --max-parents=0 --max-count=1 "${branch_pr}" )
+        DATE=$( git log --date=iso8601 --format=%cd "${COMMON_ANCESTOR}" )
 
-        # Check if we should run hypothesis tests
-        GIT_BRANCH=${GITHUB_BASE_REF:-${GITHUB_REF#refs/heads/}}
-        echo "$GIT_BRANCH"
-        if $(echo "$GIT_BRANCH" | grep -q -w '3\.\(8\|9\|10\|11\)'); then
-          echo "Branch too old for hypothesis tests"
-          echo "run-hypothesis=false" >> "$GITHUB_OUTPUT"
-        else
-          echo "Run hypothesis tests"
-          echo "run-hypothesis=true" >> "$GITHUB_OUTPUT"
-        fi
+        # Get all commits since that commit date from the base branch (eg: master or main):
+        git fetch origin "${refspec_base}" --shallow-since="${DATE}" \
+          --no-tags --prune --no-recurse-submodules
+      env:
+        branch_pr: 'origin/${{ github.event.pull_request.head.ref }}'
+        commits: ${{ github.event.pull_request.commits }}
+        refspec_base: '+${{ github.event.pull_request.base.sha }}:remotes/origin/${{ github.event.pull_request.base.ref }}'
+        refspec_pr: '+${{ github.event.pull_request.head.sha }}:remotes/origin/${{ github.event.pull_request.head.ref }}'
+
+    # We only want to run tests on PRs when related files are changed,
+    # or when someone triggers a manual workflow run.
+    - name: Compute changed files
+      id: changes
+      run: python Tools/build/compute-changes.py
 
-        # oss-fuzz maintains a configuration for fuzzing the main branch of
-        # CPython, so CIFuzz should be run only for code that is likely to be
-        # merged into the main branch; compatibility with older branches may
-        # be broken.
-        FUZZ_RELEVANT_FILES='(\.c$|\.h$|\.cpp$|^configure$|^\.github/workflows/build\.yml$|^Modules/_xxtestfuzz)'
-        if [ "$GITHUB_BASE_REF" = "main" ] && [ "$(git diff --name-only "origin/$GITHUB_BASE_REF.." | grep -qE $FUZZ_RELEVANT_FILES; echo $?)" -eq 0 ]; then
-          # The tests are pretty slow so they are executed only for PRs
-          # changing relevant files.
-          echo "Run CIFuzz tests"
-          echo "run-cifuzz=true" >> "$GITHUB_OUTPUT"
-        else
-          echo "Branch too old for CIFuzz tests; or no C files were changed"
-          echo "run-cifuzz=false" >> "$GITHUB_OUTPUT"
-        fi
     - name: Compute hash for config cache key
       id: config-hash
       run: |
         echo "hash=${{ hashFiles('configure', 'configure.ac', '.github/workflows/build.yml') }}" >> "$GITHUB_OUTPUT"
-    - name: Get a list of the changed documentation-related files
-      if: github.event_name == 'pull_request'
-      id: changed-docs-files
-      uses: Ana06/get-changed-files@v2.3.0
-      with:
-        filter: |
-          Doc/**
-          Misc/**
-          .github/workflows/reusable-docs.yml
-        format: csv  # works for paths with spaces
-    - name: Check for docs changes
-      # We only want to run this on PRs when related files are changed,
-      # or when user triggers manual workflow run.
-      if: >-
-        (
-          github.event_name == 'pull_request'
-          && steps.changed-docs-files.outputs.added_modified_renamed != ''
-        ) || github.event_name == 'workflow_dispatch'
-      id: docs-changes
-      run: |
-        echo "run-docs=true" >> "${GITHUB_OUTPUT}"
-    - name: Get a list of the MSI installer-related files
-      if: github.event_name == 'pull_request'
-      id: changed-win-msi-files
-      uses: Ana06/get-changed-files@v2.3.0
-      with:
-        filter: |
-          Tools/msi/**
-          .github/workflows/reusable-windows-msi.yml
-        format: csv  # works for paths with spaces
-    - name: Check for changes in MSI installer-related files
-      # We only want to run this on PRs when related files are changed,
-      # or when user triggers manual workflow run.
-      if: >-
-        (
-          github.event_name == 'pull_request'
-          && steps.changed-win-msi-files.outputs.added_modified_renamed != ''
-        ) || github.event_name == 'workflow_dispatch'
-      id: win-msi-changes
-      run: |
-        echo "run-win-msi=true" >> "${GITHUB_OUTPUT}"
diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
new file mode 100644
index 00000000000000..42fbec7bc5283b
--- /dev/null
+++ b/Tools/build/compute-changes.py
@@ -0,0 +1,199 @@
+"""Determine which GitHub Actions workflows to run.
+
+Called by ``.github/workflows/reusable-change-detection.yml``.
+We only want to run tests on PRs when related files are changed,
+or when someone triggers a manual workflow run.
+This improves developer experience by not doing (slow)
+unnecessary work in GHA, and saves CI resources.
+"""
+
+from __future__ import annotations
+
+import os
+import subprocess
+from dataclasses import dataclass
+from pathlib import Path
+
+TYPE_CHECKING = False
+if TYPE_CHECKING:
+    from collections.abc import Set
+
+GITHUB_CODEOWNERS_PATH = Path(".github/CODEOWNERS")
+GITHUB_WORKFLOWS_PATH = Path(".github/workflows")
+CONFIGURATION_FILE_NAMES = frozenset({
+    ".pre-commit-config.yaml",
+    ".ruff.toml",
+    "mypy.ini",
+})
+SUFFIXES_DOCUMENTATION = frozenset({".rst", ".md"})
+SUFFIXES_C_OR_CPP = frozenset({".c", ".h", ".cpp"})
+
+
+@dataclass(kw_only=True, slots=True)
+class Outputs:
+    run_ci_fuzz: bool = False
+    run_docs: bool = False
+    run_hypothesis: bool = False
+    run_tests: bool = False
+    run_windows_msi: bool = False
+
+
+def compute_changes():
+    target_branch, head_branch = git_branches()
+    if target_branch and head_branch:
+        # Getting changed files only makes sense on a pull request
+        files = get_changed_files(
+            f"origin/{target_branch}", f"origin/{head_branch}"
+        )
+        outputs = process_changed_files(files)
+    else:
+        # Otherwise, just run the tests
+        outputs = Outputs(run_tests=True)
+    outputs = process_target_branch(outputs, target_branch)
+
+    if outputs.run_tests:
+        print("Run tests")
+
+    if outputs.run_hypothesis:
+        print("Run hypothesis tests")
+
+    if outputs.run_ci_fuzz:
+        print("Run CIFuzz tests")
+    else:
+        print("Branch too old for CIFuzz tests; or no C files were changed")
+
+    if outputs.run_docs:
+        print("Build documentation")
+
+    if outputs.run_windows_msi:
+        print("Build Windows MSI")
+
+    print(outputs)
+
+    write_github_output(outputs)
+
+
+def git_branches() -> tuple[str, str]:
+    target_branch = os.environ.get("GITHUB_BASE_REF", "")
+    target_branch = target_branch.removeprefix("refs/heads/")
+    print(f"target branch: {target_branch!r}")
+
+    head_branch = os.environ.get("GITHUB_HEAD_REF", "")
+    head_branch = head_branch.removeprefix("refs/heads/")
+    print(f"head branch: {head_branch!r}")
+    return target_branch, head_branch
+
+
+def get_changed_files(ref_a: str = "main", ref_b: str = "HEAD") -> Set[Path]:
+    """List the files changed between two Git refs, filtered by change type."""
+    args = ("git", "diff", "--name-only", f"{ref_a}...{ref_b}", "--")
+    print(*args)
+    changed_files_result = subprocess.run(
+        args, stdout=subprocess.PIPE, check=True, encoding="utf-8"
+    )
+    changed_files = changed_files_result.stdout.strip().splitlines()
+    return frozenset(map(Path, filter(None, map(str.strip, changed_files))))
+
+
+def process_changed_files(changed_files: Set[Path]) -> Outputs:
+    run_tests = False
+    run_ci_fuzz = False
+    run_docs = False
+    run_windows_msi = False
+
+    for file in changed_files:
+        file_name = file.name
+        file_suffix = file.suffix
+        file_parts = file.parts
+
+        # Documentation files
+        doc_or_misc = file_parts[0] in {"Doc", "Misc"}
+        doc_file = file_suffix in SUFFIXES_DOCUMENTATION or doc_or_misc
+
+        if file.parent == GITHUB_WORKFLOWS_PATH:
+            if file_name == "build.yml":
+                run_tests = run_ci_fuzz = True
+            if file_name == "reusable-docs.yml":
+                run_docs = True
+            if file_name == "reusable-windows-msi.yml":
+                run_windows_msi = True
+
+        if not (
+            doc_file
+            or file == GITHUB_CODEOWNERS_PATH
+            or file_name in CONFIGURATION_FILE_NAMES
+        ):
+            run_tests = True
+
+        # The fuzz tests are pretty slow so they are executed only for PRs
+        # changing relevant files.
+        if file_suffix in SUFFIXES_C_OR_CPP:
+            run_ci_fuzz = True
+        if file_parts[:2] in {
+            ("configure",),
+            ("Modules", "_xxtestfuzz"),
+        }:
+            run_ci_fuzz = True
+
+        # Check for changed documentation-related files
+        if doc_file:
+            run_docs = True
+
+        # Check for changed MSI installer-related files
+        if file_parts[:2] == ("Tools", "msi"):
+            run_windows_msi = True
+
+    return Outputs(
+        run_ci_fuzz=run_ci_fuzz,
+        run_docs=run_docs,
+        run_tests=run_tests,
+        run_windows_msi=run_windows_msi,
+    )
+
+
+def process_target_branch(outputs: Outputs, git_branch: str) -> Outputs:
+    if not git_branch:
+        outputs.run_tests = True
+
+    # Check if we should run the hypothesis tests
+    if git_branch in {"3.8", "3.9", "3.10", "3.11"}:
+        print("Branch too old for hypothesis tests")
+        outputs.run_hypothesis = False
+    else:
+        outputs.run_hypothesis = outputs.run_tests
+
+    # oss-fuzz maintains a configuration for fuzzing the main branch of
+    # CPython, so CIFuzz should be run only for code that is likely to be
+    # merged into the main branch; compatibility with older branches may
+    # be broken.
+    if git_branch != "main":
+        outputs.run_ci_fuzz = False
+
+    if os.environ.get("GITHUB_EVENT_NAME", "").lower() == "workflow_dispatch":
+        outputs.run_docs = True
+        outputs.run_windows_msi = True
+
+    return outputs
+
+
+def write_github_output(outputs: Outputs) -> None:
+    # https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/store-information-in-variables#default-environment-variables
+    # https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#setting-an-output-parameter
+    if "GITHUB_OUTPUT" not in os.environ:
+        print("GITHUB_OUTPUT not defined!")
+        return
+
+    with open(os.environ["GITHUB_OUTPUT"], "a", encoding="utf-8") as f:
+        f.write(f"run-cifuzz={bool_lower(outputs.run_ci_fuzz)}\n")
+        f.write(f"run-docs={bool_lower(outputs.run_docs)}\n")
+        f.write(f"run-hypothesis={bool_lower(outputs.run_hypothesis)}\n")
+        f.write(f"run-tests={bool_lower(outputs.run_tests)}\n")
+        f.write(f"run-win-msi={bool_lower(outputs.run_windows_msi)}\n")
+
+
+def bool_lower(value: bool, /) -> str:
+    return "true" if value else "false"
+
+
+if __name__ == "__main__":
+    compute_changes()

From 4c0a7a4dd0694ac733daa772bef59a861b6eea0d Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Date: Tue, 4 Feb 2025 10:55:44 +0000
Subject: [PATCH 02/14] Hugo's review

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
---
 .github/workflows/reusable-change-detection.yml |  2 +-
 Tools/build/compute-changes.py                  | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index 5f43ead83617ee..c74b6467ffe45f 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -89,7 +89,7 @@ jobs:
         COMMON_ANCESTOR=$( git rev-list --first-parent --max-parents=0 --max-count=1 "${branch_pr}" )
         DATE=$( git log --date=iso8601 --format=%cd "${COMMON_ANCESTOR}" )
 
-        # Get all commits since that commit date from the base branch (eg: master or main):
+        # Get all commits since that commit date from the base branch (eg: main):
         git fetch origin "${refspec_base}" --shallow-since="${DATE}" \
           --no-tags --prune --no-recurse-submodules
       env:
diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index 42fbec7bc5283b..b51176facc83f0 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -25,8 +25,8 @@
     ".ruff.toml",
     "mypy.ini",
 })
-SUFFIXES_DOCUMENTATION = frozenset({".rst", ".md"})
 SUFFIXES_C_OR_CPP = frozenset({".c", ".h", ".cpp"})
+SUFFIXES_DOCUMENTATION = frozenset({".rst", ".md"})
 
 
 @dataclass(kw_only=True, slots=True)
@@ -38,7 +38,7 @@ class Outputs:
     run_windows_msi: bool = False
 
 
-def compute_changes():
+def compute_changes() -> None:
     target_branch, head_branch = git_branches()
     if target_branch and head_branch:
         # Getting changed files only makes sense on a pull request
@@ -55,7 +55,7 @@ def compute_changes():
         print("Run tests")
 
     if outputs.run_hypothesis:
-        print("Run hypothesis tests")
+        print("Run Hypothesis tests")
 
     if outputs.run_ci_fuzz:
         print("Run CIFuzz tests")
@@ -155,14 +155,14 @@ def process_target_branch(outputs: Outputs, git_branch: str) -> Outputs:
     if not git_branch:
         outputs.run_tests = True
 
-    # Check if we should run the hypothesis tests
-    if git_branch in {"3.8", "3.9", "3.10", "3.11"}:
-        print("Branch too old for hypothesis tests")
+    # Check if we should run the Hypothesis tests
+    if git_branch in {"3.9", "3.10", "3.11"}:
+        print("Branch too old for Hypothesis tests")
         outputs.run_hypothesis = False
     else:
         outputs.run_hypothesis = outputs.run_tests
 
-    # oss-fuzz maintains a configuration for fuzzing the main branch of
+    # OSS-Fuzz maintains a configuration for fuzzing the main branch of
     # CPython, so CIFuzz should be run only for code that is likely to be
     # merged into the main branch; compatibility with older branches may
     # be broken.

From 4169b462b0701d718c5f3e521454a12c42281934 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Tue, 4 Feb 2025 11:04:00 +0000
Subject: [PATCH 03/14] Simplify

---
 Tools/build/compute-changes.py | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index b51176facc83f0..847b441afab50f 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -102,34 +102,30 @@ def process_changed_files(changed_files: Set[Path]) -> Outputs:
     run_windows_msi = False
 
     for file in changed_files:
-        file_name = file.name
-        file_suffix = file.suffix
-        file_parts = file.parts
-
         # Documentation files
-        doc_or_misc = file_parts[0] in {"Doc", "Misc"}
-        doc_file = file_suffix in SUFFIXES_DOCUMENTATION or doc_or_misc
+        doc_or_misc = file.parts[0] in {"Doc", "Misc"}
+        doc_file = file.suffix in SUFFIXES_DOCUMENTATION or doc_or_misc
 
         if file.parent == GITHUB_WORKFLOWS_PATH:
-            if file_name == "build.yml":
+            if file.name == "build.yml":
                 run_tests = run_ci_fuzz = True
-            if file_name == "reusable-docs.yml":
+            if file.name == "reusable-docs.yml":
                 run_docs = True
-            if file_name == "reusable-windows-msi.yml":
+            if file.name == "reusable-windows-msi.yml":
                 run_windows_msi = True
 
         if not (
             doc_file
             or file == GITHUB_CODEOWNERS_PATH
-            or file_name in CONFIGURATION_FILE_NAMES
+            or file.name in CONFIGURATION_FILE_NAMES
         ):
             run_tests = True
 
         # The fuzz tests are pretty slow so they are executed only for PRs
         # changing relevant files.
-        if file_suffix in SUFFIXES_C_OR_CPP:
+        if file.suffix in SUFFIXES_C_OR_CPP:
             run_ci_fuzz = True
-        if file_parts[:2] in {
+        if file.parts[:2] in {
             ("configure",),
             ("Modules", "_xxtestfuzz"),
         }:
@@ -140,7 +136,7 @@ def process_changed_files(changed_files: Set[Path]) -> Outputs:
             run_docs = True
 
         # Check for changed MSI installer-related files
-        if file_parts[:2] == ("Tools", "msi"):
+        if file.parts[:2] == ("Tools", "msi"):
             run_windows_msi = True
 
     return Outputs(

From 49f02be2a35085e1e3a867251e44688c18af2c84 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Tue, 4 Feb 2025 11:12:40 +0000
Subject: [PATCH 04/14] Standardise workflow variables:

* Rename `config_hash` to `config-hash`
* Rename `run_tests` to `run-tests`
* Rename `run-win-msi` to `run-windows-msi`
* Rename `run_hypothesis` to `run-hypothesis`
* Rename `run_cifuzz` to `run-ci-fuzz`
---
 .github/workflows/build.yml                   | 54 +++++++++----------
 .../workflows/reusable-change-detection.yml   | 20 +++----
 Tools/build/compute-changes.py                |  4 +-
 3 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c10c5b4aa46ffb..db28a5494acda7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -30,7 +30,7 @@ jobs:
     #   if: fromJSON(needs.check_source.outputs.run-docs)
     #
     #   ${{
-    #        fromJSON(needs.check_source.outputs.run_tests)
+    #        fromJSON(needs.check_source.outputs.run-tests)
     #        && 'truthy-branch'
     #        || 'falsy-branch'
     #   }}
@@ -52,7 +52,7 @@ jobs:
       image: ghcr.io/python/autoconf:2025.01.02.12581854023
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     steps:
       - name: Install Git
         run: |
@@ -95,7 +95,7 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     steps:
       - uses: actions/checkout@v4
         with:
@@ -110,7 +110,7 @@ jobs:
         with:
           path: config.cache
           # Include env.pythonLocation in key to avoid changes in environment when setup-python updates Python
-          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config_hash }}-${{ env.pythonLocation }}
+          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}-${{ env.pythonLocation }}
       - name: Install Dependencies
         run: sudo ./.github/workflows/posix-deps-apt.sh
       - name: Add ccache to PATH
@@ -154,7 +154,7 @@ jobs:
       Windows
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
     needs: check_source
-    if: fromJSON(needs.check_source.outputs.run_tests)
+    if: fromJSON(needs.check_source.outputs.run-tests)
     strategy:
       fail-fast: false
       matrix:
@@ -185,7 +185,7 @@ jobs:
     name: >-  # ${{ '' } is a hack to nest jobs under the same sidebar category
       Windows MSI${{ '' }}
     needs: check_source
-    if: fromJSON(needs.check_source.outputs.run-win-msi)
+    if: fromJSON(needs.check_source.outputs.run-windows-msi)
     strategy:
       matrix:
         arch:
@@ -201,7 +201,7 @@ jobs:
       macOS
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     strategy:
       fail-fast: false
       matrix:
@@ -226,7 +226,7 @@ jobs:
           free-threading: true
     uses: ./.github/workflows/reusable-macos.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config_hash }}
+      config_hash: ${{ needs.check_source.outputs.config-hash }}
       free-threading: ${{ matrix.free-threading }}
       os: ${{ matrix.os }}
 
@@ -236,7 +236,7 @@ jobs:
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
       ${{ fromJSON(matrix.bolt) && '(bolt)' || '' }}
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     strategy:
       matrix:
         bolt:
@@ -257,7 +257,7 @@ jobs:
           bolt: true
     uses: ./.github/workflows/reusable-ubuntu.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config_hash }}
+      config_hash: ${{ needs.check_source.outputs.config-hash }}
       bolt-optimizations: ${{ matrix.bolt }}
       free-threading: ${{ matrix.free-threading }}
       os: ${{ matrix.os }}
@@ -267,7 +267,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     strategy:
       fail-fast: false
       matrix:
@@ -289,7 +289,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: config.cache
-        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config_hash }}
+        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
     - name: Register gcc problem matcher
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install Dependencies
@@ -327,17 +327,17 @@ jobs:
   build_wasi:
     name: 'WASI'
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     uses: ./.github/workflows/reusable-wasi.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config_hash }}
+      config_hash: ${{ needs.check_source.outputs.config-hash }}
 
   test_hypothesis:
     name: "Hypothesis tests on Ubuntu"
     runs-on: ubuntu-24.04
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true' && needs.check_source.outputs.run_hypothesis == 'true'
+    if: needs.check_source.outputs.run-tests == 'true' && needs.check_source.outputs.run-hypothesis == 'true'
     env:
       OPENSSL_VER: 3.0.15
       PYTHONSTRICTEXTENSIONBUILD: 1
@@ -384,7 +384,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: ${{ env.CPYTHON_BUILDDIR }}/config.cache
-        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config_hash }}
+        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
     - name: Configure CPython out-of-tree
       working-directory: ${{ env.CPYTHON_BUILDDIR }}
       run: |
@@ -453,7 +453,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     strategy:
       matrix:
         os: [ubuntu-24.04]
@@ -471,7 +471,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: config.cache
-        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config_hash }}
+        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
     - name: Register gcc problem matcher
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install Dependencies
@@ -516,7 +516,7 @@ jobs:
       Thread sanitizer
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     strategy:
       matrix:
         free-threading:
@@ -524,14 +524,14 @@ jobs:
         - true
     uses: ./.github/workflows/reusable-tsan.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config_hash }}
+      config_hash: ${{ needs.check_source.outputs.config-hash }}
       free-threading: ${{ matrix.free-threading }}
 
   cross-build-linux:
     name: Cross build Linux
     runs-on: ubuntu-latest
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     steps:
       - uses: actions/checkout@v4
         with:
@@ -542,7 +542,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: config.cache
-          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config_hash }}
+          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
       - name: Register gcc problem matcher
         run: echo "::add-matcher::.github/problem-matchers/gcc.json"
       - name: Set build dir
@@ -572,7 +572,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run_cifuzz == 'true'
+    if: needs.check_source.outputs.run-ci-fuzz == 'true'
     permissions:
       security-events: write
     strategy:
@@ -611,7 +611,7 @@ jobs:
     if: always()
 
     needs:
-    - check_source  # Transitive dependency, needed to access `run_tests` value
+    - check_source  # Transitive dependency, needed to access `run-tests` value
     - check-docs
     - check_autoconf_regen
     - check_generated_files
@@ -646,7 +646,7 @@ jobs:
             || ''
           }}
           ${{
-            needs.check_source.outputs.run_tests != 'true'
+            needs.check_source.outputs.run-tests != 'true'
             && '
             check_autoconf_regen,
             check_generated_files,
@@ -661,14 +661,14 @@ jobs:
             || ''
           }}
           ${{
-            !fromJSON(needs.check_source.outputs.run_cifuzz)
+            !fromJSON(needs.check_source.outputs.run-ci-fuzz)
             && '
             cifuzz,
             '
             || ''
           }}
           ${{
-            !fromJSON(needs.check_source.outputs.run_hypothesis)
+            !fromJSON(needs.check_source.outputs.run-hypothesis)
             && '
             test_hypothesis,
             '
diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index c74b6467ffe45f..554ac951c165c0 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -23,27 +23,27 @@ on:  # yamllint disable-line rule:truthy
       #        || 'falsy-branch'
       #   }}
       #
-      config_hash:
+      config-hash:
         description: Config hash value for use in cache keys
         value: ${{ jobs.compute-changes.outputs.config-hash }}  # str
       run-docs:
         description: Whether to build the docs
         value: ${{ jobs.compute-changes.outputs.run-docs || false }}  # bool
-      run_tests:
+      run-tests:
         description: Whether to run the regular tests
         value: ${{ jobs.compute-changes.outputs.run-tests || false }}  # bool
-      run-win-msi:
+      run-windows-msi:
         description: Whether to run the MSI installer smoke tests
         value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-win-msi || false }}
-      run_hypothesis:
+          ${{ jobs.compute-changes.outputs.run-windows-msi || false }}  # bool
+      run-hypothesis:
         description: Whether to run the Hypothesis tests
         value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-hypothesis || false }}
-      run_cifuzz:
+          ${{ jobs.compute-changes.outputs.run-hypothesis || false }}  # bool
+      run-ci-fuzz:
         description: Whether to run the CIFuzz job
         value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-cifuzz || false }}
+          ${{ jobs.compute-changes.outputs.run-ci-fuzz || false }}  # bool
 
 jobs:
   compute-changes:
@@ -52,11 +52,11 @@ jobs:
     timeout-minutes: 10
     outputs:
       config-hash: ${{ steps.config-hash.outputs.hash }}
-      run-cifuzz: ${{ steps.changes.outputs.run-cifuzz }}
+      run-ci-fuzz: ${{ steps.changes.outputs.run-ci-fuzz }}
       run-docs: ${{ steps.changes.outputs.run-docs }}
       run-hypothesis: ${{ steps.changes.outputs.run-hypothesis }}
       run-tests: ${{ steps.changes.outputs.run-tests }}
-      run-win-msi: ${{ steps.changes.outputs.run-win-msi }}
+      run-windows-msi: ${{ steps.changes.outputs.run-windows-msi }}
     steps:
     - uses: actions/setup-python@v5
       with:
diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index 847b441afab50f..4d7abeea8804fd 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -180,11 +180,11 @@ def write_github_output(outputs: Outputs) -> None:
         return
 
     with open(os.environ["GITHUB_OUTPUT"], "a", encoding="utf-8") as f:
-        f.write(f"run-cifuzz={bool_lower(outputs.run_ci_fuzz)}\n")
+        f.write(f"run-ci-fuzz={bool_lower(outputs.run_ci_fuzz)}\n")
         f.write(f"run-docs={bool_lower(outputs.run_docs)}\n")
         f.write(f"run-hypothesis={bool_lower(outputs.run_hypothesis)}\n")
         f.write(f"run-tests={bool_lower(outputs.run_tests)}\n")
-        f.write(f"run-win-msi={bool_lower(outputs.run_windows_msi)}\n")
+        f.write(f"run-windows-msi={bool_lower(outputs.run_windows_msi)}\n")
 
 
 def bool_lower(value: bool, /) -> str:

From d65e5be2b1cb6902ea3d6f70adcc509694a680da Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 07:53:00 +0000
Subject: [PATCH 05/14] no # bool
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>
---
 .github/workflows/reusable-change-detection.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index 554ac951c165c0..88a9188dc58f76 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -35,15 +35,15 @@ on:  # yamllint disable-line rule:truthy
       run-windows-msi:
         description: Whether to run the MSI installer smoke tests
         value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-windows-msi || false }}  # bool
+          ${{ jobs.compute-changes.outputs.run-windows-msi || false }}
       run-hypothesis:
         description: Whether to run the Hypothesis tests
         value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-hypothesis || false }}  # bool
+          ${{ jobs.compute-changes.outputs.run-hypothesis || false }}
       run-ci-fuzz:
         description: Whether to run the CIFuzz job
         value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-ci-fuzz || false }}  # bool
+          ${{ jobs.compute-changes.outputs.run-ci-fuzz || false }}
 
 jobs:
   compute-changes:

From b40113e52f3066756fd6b39188f6aae3e6632df4 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 14:43:31 +0000
Subject: [PATCH 06/14] Add step name

---
 .github/workflows/reusable-change-detection.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index 88a9188dc58f76..fa4185c62b31d4 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -58,7 +58,8 @@ jobs:
       run-tests: ${{ steps.changes.outputs.run-tests }}
       run-windows-msi: ${{ steps.changes.outputs.run-windows-msi }}
     steps:
-    - uses: actions/setup-python@v5
+    - name: Set up Python
+      uses: actions/setup-python@v5
       with:
         python-version: "3"
 

From 1ee4e0e4de7b26bb718ef301b3e771ae95619f9a Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 14:48:06 +0000
Subject: [PATCH 07/14] empty


From e183b1521a715faeb1e7516c3a58b178090931b9 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 15:15:39 +0000
Subject: [PATCH 08/14] Merge run_hypothesis into run_tests

---
 .github/workflows/build.yml                     | 10 ++--------
 .github/workflows/reusable-change-detection.yml |  5 -----
 Tools/build/compute-changes.py                  | 12 ------------
 3 files changed, 2 insertions(+), 25 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index db28a5494acda7..5de748f5870aaa 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -337,7 +337,7 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 60
     needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true' && needs.check_source.outputs.run-hypothesis == 'true'
+    if: needs.check_source.outputs.run-tests == 'true'
     env:
       OPENSSL_VER: 3.0.15
       PYTHONSTRICTEXTENSIONBUILD: 1
@@ -657,6 +657,7 @@ jobs:
             build_windows,
             build_asan,
             build_tsan,
+            test_hypothesis,
             '
             || ''
           }}
@@ -667,11 +668,4 @@ jobs:
             '
             || ''
           }}
-          ${{
-            !fromJSON(needs.check_source.outputs.run-hypothesis)
-            && '
-            test_hypothesis,
-            '
-            || ''
-          }}
         jobs: ${{ toJSON(needs) }}
diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index fa4185c62b31d4..57475a454b5b9b 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -36,10 +36,6 @@ on:  # yamllint disable-line rule:truthy
         description: Whether to run the MSI installer smoke tests
         value: >-  # bool
           ${{ jobs.compute-changes.outputs.run-windows-msi || false }}
-      run-hypothesis:
-        description: Whether to run the Hypothesis tests
-        value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-hypothesis || false }}
       run-ci-fuzz:
         description: Whether to run the CIFuzz job
         value: >-  # bool
@@ -54,7 +50,6 @@ jobs:
       config-hash: ${{ steps.config-hash.outputs.hash }}
       run-ci-fuzz: ${{ steps.changes.outputs.run-ci-fuzz }}
       run-docs: ${{ steps.changes.outputs.run-docs }}
-      run-hypothesis: ${{ steps.changes.outputs.run-hypothesis }}
       run-tests: ${{ steps.changes.outputs.run-tests }}
       run-windows-msi: ${{ steps.changes.outputs.run-windows-msi }}
     steps:
diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index 4d7abeea8804fd..b0816553556b8a 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -33,7 +33,6 @@
 class Outputs:
     run_ci_fuzz: bool = False
     run_docs: bool = False
-    run_hypothesis: bool = False
     run_tests: bool = False
     run_windows_msi: bool = False
 
@@ -54,9 +53,6 @@ def compute_changes() -> None:
     if outputs.run_tests:
         print("Run tests")
 
-    if outputs.run_hypothesis:
-        print("Run Hypothesis tests")
-
     if outputs.run_ci_fuzz:
         print("Run CIFuzz tests")
     else:
@@ -151,13 +147,6 @@ def process_target_branch(outputs: Outputs, git_branch: str) -> Outputs:
     if not git_branch:
         outputs.run_tests = True
 
-    # Check if we should run the Hypothesis tests
-    if git_branch in {"3.9", "3.10", "3.11"}:
-        print("Branch too old for Hypothesis tests")
-        outputs.run_hypothesis = False
-    else:
-        outputs.run_hypothesis = outputs.run_tests
-
     # OSS-Fuzz maintains a configuration for fuzzing the main branch of
     # CPython, so CIFuzz should be run only for code that is likely to be
     # merged into the main branch; compatibility with older branches may
@@ -182,7 +171,6 @@ def write_github_output(outputs: Outputs) -> None:
     with open(os.environ["GITHUB_OUTPUT"], "a", encoding="utf-8") as f:
         f.write(f"run-ci-fuzz={bool_lower(outputs.run_ci_fuzz)}\n")
         f.write(f"run-docs={bool_lower(outputs.run_docs)}\n")
-        f.write(f"run-hypothesis={bool_lower(outputs.run_hypothesis)}\n")
         f.write(f"run-tests={bool_lower(outputs.run_tests)}\n")
         f.write(f"run-windows-msi={bool_lower(outputs.run_windows_msi)}\n")
 

From e03d2959c1ebc84c07b36e67f1a1623045fe4b70 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 15:22:51 +0000
Subject: [PATCH 09/14] Use github.event.repository.default_branch per review

---
 .github/workflows/reusable-change-detection.yml |  2 ++
 Tools/build/compute-changes.py                  | 12 ++++++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-change-detection.yml
index 57475a454b5b9b..409a4a2f615e90 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-change-detection.yml
@@ -99,6 +99,8 @@ jobs:
     - name: Compute changed files
       id: changes
       run: python Tools/build/compute-changes.py
+      env:
+        GITHUB_DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
 
     - name: Compute hash for config cache key
       id: config-hash
diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index b0816553556b8a..629223a8b09c66 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -18,6 +18,7 @@
 if TYPE_CHECKING:
     from collections.abc import Set
 
+GITHUB_DEFAULT_BRANCH = os.environ.get("GITHUB_DEFAULT_BRANCH", "")
 GITHUB_CODEOWNERS_PATH = Path(".github/CODEOWNERS")
 GITHUB_WORKFLOWS_PATH = Path(".github/workflows")
 CONFIGURATION_FILE_NAMES = frozenset({
@@ -80,7 +81,9 @@ def git_branches() -> tuple[str, str]:
     return target_branch, head_branch
 
 
-def get_changed_files(ref_a: str = "main", ref_b: str = "HEAD") -> Set[Path]:
+def get_changed_files(
+    ref_a: str = GITHUB_DEFAULT_BRANCH, ref_b: str = "HEAD"
+) -> Set[Path]:
     """List the files changed between two Git refs, filtered by change type."""
     args = ("git", "diff", "--name-only", f"{ref_a}...{ref_b}", "--")
     print(*args)
@@ -147,11 +150,8 @@ def process_target_branch(outputs: Outputs, git_branch: str) -> Outputs:
     if not git_branch:
         outputs.run_tests = True
 
-    # OSS-Fuzz maintains a configuration for fuzzing the main branch of
-    # CPython, so CIFuzz should be run only for code that is likely to be
-    # merged into the main branch; compatibility with older branches may
-    # be broken.
-    if git_branch != "main":
+    # CIFuzz / OSS-Fuzz compatibility with older branches may be broken.
+    if git_branch != GITHUB_DEFAULT_BRANCH:
         outputs.run_ci_fuzz = False
 
     if os.environ.get("GITHUB_EVENT_NAME", "").lower() == "workflow_dispatch":

From 05253e32b8f6322d6b46da2678c2736d9e654f52 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 15:26:07 +0000
Subject: [PATCH 10/14] Update Tools/build/compute-changes.py
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>
---
 Tools/build/compute-changes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index 629223a8b09c66..0bd10d72db7f42 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -18,7 +18,7 @@
 if TYPE_CHECKING:
     from collections.abc import Set
 
-GITHUB_DEFAULT_BRANCH = os.environ.get("GITHUB_DEFAULT_BRANCH", "")
+GITHUB_DEFAULT_BRANCH = os.environ["GITHUB_DEFAULT_BRANCH]
 GITHUB_CODEOWNERS_PATH = Path(".github/CODEOWNERS")
 GITHUB_WORKFLOWS_PATH = Path(".github/workflows")
 CONFIGURATION_FILE_NAMES = frozenset({

From f45c009327d3dad6668c64b682eb72166a31c1cb Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 15:27:47 +0000
Subject: [PATCH 11/14] fix syntax error in suggestion

---
 Tools/build/compute-changes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index 0bd10d72db7f42..162f6fd6eeb636 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -18,7 +18,7 @@
 if TYPE_CHECKING:
     from collections.abc import Set
 
-GITHUB_DEFAULT_BRANCH = os.environ["GITHUB_DEFAULT_BRANCH]
+GITHUB_DEFAULT_BRANCH = os.environ["GITHUB_DEFAULT_BRANCH"]
 GITHUB_CODEOWNERS_PATH = Path(".github/CODEOWNERS")
 GITHUB_WORKFLOWS_PATH = Path(".github/workflows")
 CONFIGURATION_FILE_NAMES = frozenset({

From e265fa5fadb9946ca017327989fec1af5db7dfb8 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 15:54:21 +0000
Subject: [PATCH 12/14] Rename to "context" from "change-detection"

---
 .github/workflows/build.yml                   | 88 +++++++++----------
 ...nge-detection.yml => reusable-context.yml} | 34 +++----
 Tools/build/compute-changes.py                |  2 +-
 3 files changed, 58 insertions(+), 66 deletions(-)
 rename .github/workflows/{reusable-change-detection.yml => reusable-context.yml} (70%)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 5de748f5870aaa..b58e80f69933c5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -22,15 +22,15 @@ env:
   FORCE_COLOR: 1
 
 jobs:
-  check_source:
+  build-context:
     name: Change detection
     # To use boolean outputs from this job, parse them as JSON.
     # Here's some examples:
     #
-    #   if: fromJSON(needs.check_source.outputs.run-docs)
+    #   if: fromJSON(needs.build-context.outputs.run-docs)
     #
     #   ${{
-    #        fromJSON(needs.check_source.outputs.run-tests)
+    #        fromJSON(needs.build-context.outputs.run-tests)
     #        && 'truthy-branch'
     #        || 'falsy-branch'
     #   }}
@@ -39,8 +39,8 @@ jobs:
 
   check-docs:
     name: Docs
-    needs: check_source
-    if: fromJSON(needs.check_source.outputs.run-docs)
+    needs: build-context
+    if: fromJSON(needs.build-context.outputs.run-docs)
     uses: ./.github/workflows/reusable-docs.yml
 
   check_autoconf_regen:
@@ -51,8 +51,8 @@ jobs:
     container:
       image: ghcr.io/python/autoconf:2025.01.02.12581854023
     timeout-minutes: 60
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     steps:
       - name: Install Git
         run: |
@@ -94,8 +94,8 @@ jobs:
     # reproducible: to get the same tools versions (autoconf, aclocal, ...)
     runs-on: ubuntu-24.04
     timeout-minutes: 60
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     steps:
       - uses: actions/checkout@v4
         with:
@@ -110,7 +110,7 @@ jobs:
         with:
           path: config.cache
           # Include env.pythonLocation in key to avoid changes in environment when setup-python updates Python
-          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}-${{ env.pythonLocation }}
+          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.build-context.outputs.config-hash }}-${{ env.pythonLocation }}
       - name: Install Dependencies
         run: sudo ./.github/workflows/posix-deps-apt.sh
       - name: Add ccache to PATH
@@ -153,8 +153,8 @@ jobs:
     name: >-
       Windows
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
-    needs: check_source
-    if: fromJSON(needs.check_source.outputs.run-tests)
+    needs: build-context
+    if: fromJSON(needs.build-context.outputs.run-tests)
     strategy:
       fail-fast: false
       matrix:
@@ -184,8 +184,8 @@ jobs:
   build_windows_msi:
     name: >-  # ${{ '' } is a hack to nest jobs under the same sidebar category
       Windows MSI${{ '' }}
-    needs: check_source
-    if: fromJSON(needs.check_source.outputs.run-windows-msi)
+    needs: build-context
+    if: fromJSON(needs.build-context.outputs.run-windows-msi)
     strategy:
       matrix:
         arch:
@@ -200,8 +200,8 @@ jobs:
     name: >-
       macOS
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     strategy:
       fail-fast: false
       matrix:
@@ -226,7 +226,7 @@ jobs:
           free-threading: true
     uses: ./.github/workflows/reusable-macos.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config-hash }}
+      config_hash: ${{ needs.build-context.outputs.config-hash }}
       free-threading: ${{ matrix.free-threading }}
       os: ${{ matrix.os }}
 
@@ -235,8 +235,8 @@ jobs:
       Ubuntu
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
       ${{ fromJSON(matrix.bolt) && '(bolt)' || '' }}
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     strategy:
       matrix:
         bolt:
@@ -257,7 +257,7 @@ jobs:
           bolt: true
     uses: ./.github/workflows/reusable-ubuntu.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config-hash }}
+      config_hash: ${{ needs.build-context.outputs.config-hash }}
       bolt-optimizations: ${{ matrix.bolt }}
       free-threading: ${{ matrix.free-threading }}
       os: ${{ matrix.os }}
@@ -266,8 +266,8 @@ jobs:
     name: 'Ubuntu SSL tests with OpenSSL'
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     strategy:
       fail-fast: false
       matrix:
@@ -289,7 +289,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: config.cache
-        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
+        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.build-context.outputs.config-hash }}
     - name: Register gcc problem matcher
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install Dependencies
@@ -326,18 +326,18 @@ jobs:
 
   build_wasi:
     name: 'WASI'
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     uses: ./.github/workflows/reusable-wasi.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config-hash }}
+      config_hash: ${{ needs.build-context.outputs.config-hash }}
 
   test_hypothesis:
     name: "Hypothesis tests on Ubuntu"
     runs-on: ubuntu-24.04
     timeout-minutes: 60
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     env:
       OPENSSL_VER: 3.0.15
       PYTHONSTRICTEXTENSIONBUILD: 1
@@ -384,7 +384,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: ${{ env.CPYTHON_BUILDDIR }}/config.cache
-        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
+        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.build-context.outputs.config-hash }}
     - name: Configure CPython out-of-tree
       working-directory: ${{ env.CPYTHON_BUILDDIR }}
       run: |
@@ -452,8 +452,8 @@ jobs:
     name: 'Address sanitizer'
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     strategy:
       matrix:
         os: [ubuntu-24.04]
@@ -471,7 +471,7 @@ jobs:
       uses: actions/cache@v4
       with:
         path: config.cache
-        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
+        key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.build-context.outputs.config-hash }}
     - name: Register gcc problem matcher
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install Dependencies
@@ -515,8 +515,8 @@ jobs:
     name: >-
       Thread sanitizer
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     strategy:
       matrix:
         free-threading:
@@ -524,14 +524,14 @@ jobs:
         - true
     uses: ./.github/workflows/reusable-tsan.yml
     with:
-      config_hash: ${{ needs.check_source.outputs.config-hash }}
+      config_hash: ${{ needs.build-context.outputs.config-hash }}
       free-threading: ${{ matrix.free-threading }}
 
   cross-build-linux:
     name: Cross build Linux
     runs-on: ubuntu-latest
-    needs: check_source
-    if: needs.check_source.outputs.run-tests == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-tests == 'true'
     steps:
       - uses: actions/checkout@v4
         with:
@@ -542,7 +542,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: config.cache
-          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.check_source.outputs.config-hash }}
+          key: ${{ github.job }}-${{ runner.os }}-${{ env.IMAGE_VERSION }}-${{ needs.build-context.outputs.config-hash }}
       - name: Register gcc problem matcher
         run: echo "::add-matcher::.github/problem-matchers/gcc.json"
       - name: Set build dir
@@ -571,8 +571,8 @@ jobs:
     name: CIFuzz
     runs-on: ubuntu-latest
     timeout-minutes: 60
-    needs: check_source
-    if: needs.check_source.outputs.run-ci-fuzz == 'true'
+    needs: build-context
+    if: needs.build-context.outputs.run-ci-fuzz == 'true'
     permissions:
       security-events: write
     strategy:
@@ -611,7 +611,7 @@ jobs:
     if: always()
 
     needs:
-    - check_source  # Transitive dependency, needed to access `run-tests` value
+    - build-context  # Transitive dependency, needed to access `run-tests` value
     - check-docs
     - check_autoconf_regen
     - check_generated_files
@@ -639,14 +639,14 @@ jobs:
           test_hypothesis,
         allowed-skips: >-
           ${{
-            !fromJSON(needs.check_source.outputs.run-docs)
+            !fromJSON(needs.build-context.outputs.run-docs)
             && '
             check-docs,
             '
             || ''
           }}
           ${{
-            needs.check_source.outputs.run-tests != 'true'
+            needs.build-context.outputs.run-tests != 'true'
             && '
             check_autoconf_regen,
             check_generated_files,
@@ -662,7 +662,7 @@ jobs:
             || ''
           }}
           ${{
-            !fromJSON(needs.check_source.outputs.run-ci-fuzz)
+            !fromJSON(needs.build-context.outputs.run-ci-fuzz)
             && '
             cifuzz,
             '
diff --git a/.github/workflows/reusable-change-detection.yml b/.github/workflows/reusable-context.yml
similarity index 70%
rename from .github/workflows/reusable-change-detection.yml
rename to .github/workflows/reusable-context.yml
index 409a4a2f615e90..f8d1aee7f1a01f 100644
--- a/.github/workflows/reusable-change-detection.yml
+++ b/.github/workflows/reusable-context.yml
@@ -1,24 +1,18 @@
-name: Reusable change detection
+name: Reusable build context
 
 on:  # yamllint disable-line rule:truthy
   workflow_call:
     outputs:
-      # Some of the referenced steps set outputs conditionally and there may be
-      # cases when referencing them evaluates to empty strings. It is nice to
-      # work with proper booleans so they have to be evaluated through JSON
-      # conversion in the expressions. However, empty strings used like that
-      # may trigger all sorts of undefined and hard-to-debug behaviors in
-      # GitHub Actions CI/CD. To help with this, all of the outputs set here
-      # that are meant to be used as boolean flags (and not arbitrary strings),
-      # MUST have fallbacks with default values set. A common pattern would be
-      # to add ` || false` to all such expressions here, in the output
-      # definitions. They can then later be safely used through the following
-      # idiom in job conditionals and other expressions. Here's some examples:
+      # Every referenced step MUST always its set output variable,
+      # either via ``Tools/build/compute-changes.py`` or in this workflow file.
+      # Boolean outputs (generally prefixed ``run-``) can then later be used
+      # safely through the following idiom in job conditionals and other
+      # expressions. Here's some examples:
       #
-      #   if: fromJSON(needs.change-detection.outputs.run-docs)
+      #   if: fromJSON(needs.build-context.outputs.run-tests)
       #
       #   ${{
-      #        fromJSON(needs.change-detection.outputs.run-tests)
+      #        fromJSON(needs.build-context.outputs.run-tests)
       #        && 'truthy-branch'
       #        || 'falsy-branch'
       #   }}
@@ -28,22 +22,20 @@ on:  # yamllint disable-line rule:truthy
         value: ${{ jobs.compute-changes.outputs.config-hash }}  # str
       run-docs:
         description: Whether to build the docs
-        value: ${{ jobs.compute-changes.outputs.run-docs || false }}  # bool
+        value: ${{ jobs.compute-changes.outputs.run-docs }}  # bool
       run-tests:
         description: Whether to run the regular tests
-        value: ${{ jobs.compute-changes.outputs.run-tests || false }}  # bool
+        value: ${{ jobs.compute-changes.outputs.run-tests  }}  # bool
       run-windows-msi:
         description: Whether to run the MSI installer smoke tests
-        value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-windows-msi || false }}
+        value: ${{ jobs.compute-changes.outputs.run-windows-msi }}  # bool
       run-ci-fuzz:
         description: Whether to run the CIFuzz job
-        value: >-  # bool
-          ${{ jobs.compute-changes.outputs.run-ci-fuzz || false }}
+        value: ${{ jobs.compute-changes.outputs.run-ci-fuzz }}  # bool
 
 jobs:
   compute-changes:
-    name: Compute changed files
+    name: Create context from changed files
     runs-on: ubuntu-latest
     timeout-minutes: 10
     outputs:
diff --git a/Tools/build/compute-changes.py b/Tools/build/compute-changes.py
index 162f6fd6eeb636..105ba58cc9d941 100644
--- a/Tools/build/compute-changes.py
+++ b/Tools/build/compute-changes.py
@@ -1,6 +1,6 @@
 """Determine which GitHub Actions workflows to run.
 
-Called by ``.github/workflows/reusable-change-detection.yml``.
+Called by ``.github/workflows/reusable-context.yml``.
 We only want to run tests on PRs when related files are changed,
 or when someone triggers a manual workflow run.
 This improves developer experience by not doing (slow)

From 06ef1172b2b19ff1295132ca41a5d4f53bbb7d05 Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 15:59:33 +0000
Subject: [PATCH 13/14] fixup! Rename to "context" from "change-detection"

---
 .github/workflows/build.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b58e80f69933c5..dc2f4858be6e8c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -35,7 +35,7 @@ jobs:
     #        || 'falsy-branch'
     #   }}
     #
-    uses: ./.github/workflows/reusable-change-detection.yml
+    uses: ./.github/workflows/reusable-context.yml
 
   check-docs:
     name: Docs

From f52c88f163c06d8e82e8870f72072a906cd5bc7b Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Wed, 5 Feb 2025 16:16:08 +0000
Subject: [PATCH 14/14] fixup! Rename to "context" from "change-detection"

---
 .github/workflows/reusable-context.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/reusable-context.yml b/.github/workflows/reusable-context.yml
index f8d1aee7f1a01f..fa4df6f29711db 100644
--- a/.github/workflows/reusable-context.yml
+++ b/.github/workflows/reusable-context.yml
@@ -3,7 +3,7 @@ name: Reusable build context
 on:  # yamllint disable-line rule:truthy
   workflow_call:
     outputs:
-      # Every referenced step MUST always its set output variable,
+      # Every referenced step MUST always set its output variable,
       # either via ``Tools/build/compute-changes.py`` or in this workflow file.
       # Boolean outputs (generally prefixed ``run-``) can then later be used
       # safely through the following idiom in job conditionals and other