python_repository: Exclude pycache files (bazel-contrib#907)

illicitonion · web-flow · commit f94c19592292 · 2023-01-24T08:52:45.000-08:00
python_repository: Exclude pycache files when root

Some of these are missing from the upstream python distributions, and
when they are, if running as root, this causes the files to be generated
the first time their associated .py file is evaluated, causing analysis
and execution cache misses due to extra files matching the repository glob.
diff --git a/python/repositories.bzl b/python/repositories.bzl
@@ -196,8 +196,20 @@ def _python_repository_impl(rctx):
 
     python_bin = "python.exe" if ("windows" in platform) else "bin/python3"
 
+    glob_include = []
+
+    if rctx.attr.ignore_root_user_error:
+        glob_include += [
+            "# These pycache files are created on first use of the associated python files.",
+            "# Exclude them from the glob because otherwise between the first time and second time a python toolchain is used,",
+            "# the definition of this filegroup will change, and depending rules will get invalidated.",
+            "# See https://github.com/bazelbuild/rules_python/issues/1008 for unconditionally adding these to toolchains so we can stop ignoring them.",
+            "**/__pycache__/*.pyc",
+            "**/__pycache__/*.pyo",
+        ]
+
     if "windows" in platform:
-        glob_include = [
+        glob_include += [
             "*.exe",
             "*.dll",
             "bin/**",
@@ -210,7 +222,7 @@ def _python_repository_impl(rctx):
             "share/**",
         ]
     else:
-        glob_include = [
+        glob_include += [
             "bin/**",
             "extensions/**",
             "include/**",
