diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 1778b2a6..453aad70 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "4.0.2"
+  ".": "4.0.3"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 68430064..154ee8e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,23 @@
 
 # Change Log
 
+## [4.0.3](https://github.com/ruby-git/ruby-git/compare/v4.0.2...v4.0.3) (2025-07-08)
+
+
+### Bug Fixes
+
+* Correct the deprecation horizon for Git deprecations ([b7b7f38](https://github.com/ruby-git/ruby-git/commit/b7b7f38ccb88ba719e8ea7cb3fea14474b19a00c))
+* Fix Rubocop Layout/EmptyLinesAroundClassBody offense ([1de27da](https://github.com/ruby-git/ruby-git/commit/1de27daabed18b47a42539fe69b735d8ee90cbbb))
+* Internally create a Stash with non-deprecated initializer args ([8b9b9e2](https://github.com/ruby-git/ruby-git/commit/8b9b9e2f3b3fa525973785f642331317ade35936))
+* Report correct line number in deprecation warnings ([cca0deb](https://github.com/ruby-git/ruby-git/commit/cca0debb4166c809af76f9dc586e4fd06e142d44))
+* Un-deprecate Git::Diff methods ([761b6ff](https://github.com/ruby-git/ruby-git/commit/761b6ffcd363f4329a9cbafbf1379513a19ff174))
+
+
+### Other Changes
+
+* Make tests that emit a deprecation warning fail ([7e211d7](https://github.com/ruby-git/ruby-git/commit/7e211d7b2b7cc8d9da4a860361bef52280a5e73b))
+* Update all tests to not use deprecated features ([33ab0e2](https://github.com/ruby-git/ruby-git/commit/33ab0e255e229e22d84b14a4d4f5fb829c1fe37c))
+
 ## [4.0.2](https://github.com/ruby-git/ruby-git/compare/v4.0.1...v4.0.2) (2025-07-08)
 
 
diff --git a/lib/git.rb b/lib/git.rb
index 638b77d8..e23e2a07 100644
--- a/lib/git.rb
+++ b/lib/git.rb
@@ -4,7 +4,7 @@
 require 'active_support/deprecation'
 
 module Git
-  Deprecation = ActiveSupport::Deprecation.new('3.0', 'Git')
+  Deprecation = ActiveSupport::Deprecation.new('5.0.0', 'Git')
 end
 
 require 'git/author'
diff --git a/lib/git/diff.rb b/lib/git/diff.rb
index c9770e81..aad1b712 100644
--- a/lib/git/diff.rb
+++ b/lib/git/diff.rb
@@ -38,38 +38,31 @@ def each(&)
       @full_diff_files.map { |file| file[1] }.each(&)
     end
 
+    def size
+      stats_provider.total[:files]
+    end
+
     #
     # DEPRECATED METHODS
     #
 
     def name_status
-      Git::Deprecation.warn('Git::Diff#name_status is deprecated. Use Git::Base#diff_path_status instead.')
       path_status_provider.to_h
     end
 
-    def size
-      Git::Deprecation.warn('Git::Diff#size is deprecated. Use Git::Base#diff_stats(...).total[:files] instead.')
-      stats_provider.total[:files]
-    end
-
     def lines
-      Git::Deprecation.warn('Git::Diff#lines is deprecated. Use Git::Base#diff_stats(...).lines instead.')
       stats_provider.lines
     end
 
     def deletions
-      Git::Deprecation.warn('Git::Diff#deletions is deprecated. Use Git::Base#diff_stats(...).deletions instead.')
       stats_provider.deletions
     end
 
     def insertions
-      Git::Deprecation.warn('Git::Diff#insertions is deprecated. Use Git::Base#diff_stats(...).insertions instead.')
       stats_provider.insertions
     end
 
     def stats
-      Git::Deprecation.warn('Git::Diff#stats is deprecated. Use Git::Base#diff_stats instead.')
-      # CORRECTED: Re-create the original hash structure for backward compatibility
       {
         files: stats_provider.files,
         total: stats_provider.total
diff --git a/lib/git/log.rb b/lib/git/log.rb
index c5b3c6da..644322d9 100644
--- a/lib/git/log.rb
+++ b/lib/git/log.rb
@@ -90,28 +90,56 @@ def execute
 
     # @deprecated Use {#execute} and call `each` on the result.
     def each(&)
-      deprecate_and_run
+      Git::Deprecation.warn(
+        'Calling Git::Log#each is deprecated. Call #execute and then #each on the result object.'
+      )
+      run_log_if_dirty
       @commits.each(&)
     end
 
     # @deprecated Use {#execute} and call `size` on the result.
     def size
-      deprecate_and_run
+      Git::Deprecation.warn(
+        'Calling Git::Log#size is deprecated. Call #execute and then #size on the result object.'
+      )
+      run_log_if_dirty
       @commits&.size
     end
 
     # @deprecated Use {#execute} and call `to_s` on the result.
     def to_s
-      deprecate_and_run
+      Git::Deprecation.warn(
+        'Calling Git::Log#to_s is deprecated. Call #execute and then #to_s on the result object.'
+      )
+      run_log_if_dirty
       @commits&.map(&:to_s)&.join("\n")
     end
 
     # @deprecated Use {#execute} and call the method on the result.
-    %i[first last []].each do |method_name|
-      define_method(method_name) do |*args|
-        deprecate_and_run
-        @commits&.public_send(method_name, *args)
-      end
+    def first
+      Git::Deprecation.warn(
+        'Calling Git::Log#first is deprecated. Call #execute and then #first on the result object.'
+      )
+      run_log_if_dirty
+      @commits&.first
+    end
+
+    # @deprecated Use {#execute} and call the method on the result.
+    def last
+      Git::Deprecation.warn(
+        'Calling Git::Log#last is deprecated. Call #execute and then #last on the result object.'
+      )
+      run_log_if_dirty
+      @commits&.last
+    end
+
+    # @deprecated Use {#execute} and call the method on the result.
+    def [](index)
+      Git::Deprecation.warn(
+        'Calling Git::Log#[] is deprecated. Call #execute and then #[] on the result object.'
+      )
+      run_log_if_dirty
+      @commits&.[](index)
     end
 
     # @!endgroup
@@ -131,13 +159,5 @@ def run_log_if_dirty
       @commits = log_data.map { |c| Git::Object::Commit.new(@base, c['sha'], c) }
       @dirty = false
     end
-
-    def deprecate_and_run(method = caller_locations(1, 1)[0].label)
-      Git::Deprecation.warn(
-        "Calling Git::Log##{method} is deprecated. " \
-        "Call #execute and then ##{method} on the result object."
-      )
-      run_log_if_dirty
-    end
   end
 end
diff --git a/lib/git/stashes.rb b/lib/git/stashes.rb
index d3eb4cfc..abef5e8c 100644
--- a/lib/git/stashes.rb
+++ b/lib/git/stashes.rb
@@ -12,7 +12,7 @@ def initialize(base)
 
       @base.lib.stashes_all.each do |indexed_message|
         _index, message = indexed_message
-        @stashes.unshift(Git::Stash.new(@base, message, true))
+        @stashes.unshift(Git::Stash.new(@base, message, save: true))
       end
     end
 
diff --git a/lib/git/version.rb b/lib/git/version.rb
index bd22d777..0b43866a 100644
--- a/lib/git/version.rb
+++ b/lib/git/version.rb
@@ -3,5 +3,5 @@
 module Git
   # The current gem version
   # @return [String] the current gem version.
-  VERSION = '4.0.2'
+  VERSION = '4.0.3'
 end
diff --git a/tests/test_helper.rb b/tests/test_helper.rb
index fb4ac4b3..aa42eedd 100644
--- a/tests/test_helper.rb
+++ b/tests/test_helper.rb
@@ -12,8 +12,19 @@
 $stdout.sync = true
 $stderr.sync = true
 
-# Silence deprecation warnings during tests
-Git::Deprecation.behavior = :silence
+# Make tests that emit a deprecation warning fail
+
+# Deprecation warnings should not be ignored.
+
+# This is important so that:
+# * when a user sees a deprecation warning, they can be confident it is coming from
+#   their code and not this gem
+# * test output is clean and does not contain noisey deprecation warnings
+
+# Tests whose purpose is to test that a deprecation warning is issued in the right
+# circumstance should mock Git::Deprecation#warn to avoid raising an error.
+#
+Git::Deprecation.behavior = :raise
 
 module Test
   module Unit
diff --git a/tests/units/test_base.rb b/tests/units/test_base.rb
index 65c67637..9e818d86 100644
--- a/tests/units/test_base.rb
+++ b/tests/units/test_base.rb
@@ -88,11 +88,13 @@ def test_commit
       git.add('test_file_1')
       git.add('test_file_2')
 
-      base_commit_id = git.log[0].objectish
+      commits = git.log.execute
+      base_commit_id = commits[0].objectish
 
       git.commit('Test Commit')
 
-      original_commit_id = git.log[0].objectish
+      commits = git.log.execute
+      original_commit_id = commits[0].objectish
 
       create_file('test_commit/test_file_3', 'content test_file_3')
 
@@ -100,8 +102,9 @@ def test_commit
 
       git.commit(nil, amend: true)
 
-      assert(git.log[0].objectish != original_commit_id)
-      assert(git.log[1].objectish == base_commit_id)
+      commits = git.log.execute
+      assert(commits[0].objectish != original_commit_id)
+      assert(commits[1].objectish == base_commit_id)
     end
   end
 end
diff --git a/tests/units/test_commit_with_empty_message.rb b/tests/units/test_commit_with_empty_message.rb
index 41645d27..8ef6d890 100755
--- a/tests/units/test_commit_with_empty_message.rb
+++ b/tests/units/test_commit_with_empty_message.rb
@@ -20,7 +20,8 @@ def test_with_allow_empty_message_option
     Dir.mktmpdir do |dir|
       git = Git.init(dir)
       git.commit('', { allow_empty: true, allow_empty_message: true })
-      assert_equal(1, git.log.to_a.size)
+      commits = git.log.execute
+      assert_equal(1, commits.to_a.size)
     end
   end
 end
diff --git a/tests/units/test_git_dir.rb b/tests/units/test_git_dir.rb
index 31e583f3..77f9ae14 100644
--- a/tests/units/test_git_dir.rb
+++ b/tests/units/test_git_dir.rb
@@ -62,11 +62,13 @@ def test_git_dir_outside_work_tree
         # * the commit was added to the log
         #
         max_log_size = 100
-        assert_equal(64, git.log(max_log_size).size)
+        commits = git.log(max_log_size).execute
+        assert_equal(64, commits.size)
         git.add(file)
         git.commit('This is a new commit')
         assert_equal(false, git.status.changed?(file))
-        assert_equal(65, git.log(max_log_size).size)
+        commits = git.log(max_log_size).execute
+        assert_equal(65, commits.size)
       end
     end
   end
diff --git a/tests/units/test_git_path.rb b/tests/units/test_git_path.rb
index 40e25fd9..1d8a2311 100644
--- a/tests/units/test_git_path.rb
+++ b/tests/units/test_git_path.rb
@@ -9,18 +9,18 @@ def setup
   end
 
   def test_initalize_with_good_path_and_check_path
-    path = Git::Path.new(@git.index.to_s, true)
+    path = Git::Path.new(@git.index.to_s, must_exist: true)
     assert_equal @git.index.to_s, path.to_s
   end
 
   def test_initialize_with_bad_path_and_check_path
     assert_raises ArgumentError do
-      Git::Path.new('/this path does not exist', true)
+      Git::Path.new('/this path does not exist', must_exist: true)
     end
   end
 
   def test_initialize_with_bad_path_and_no_check
-    path = Git::Path.new('/this path does not exist', false)
+    path = Git::Path.new('/this path does not exist', must_exist: false)
     assert path.to_s.end_with?('/this path does not exist')
 
     assert(path.to_s.match(%r{^(?:[A-Z]:)?/this path does not exist$}))
diff --git a/tests/units/test_index_ops.rb b/tests/units/test_index_ops.rb
index 233673c8..c4c0aba4 100644
--- a/tests/units/test_index_ops.rb
+++ b/tests/units/test_index_ops.rb
@@ -94,9 +94,10 @@ def test_revert
       g.commit('second-commit')
       g.gcommit('HEAD')
 
-      commits = g.log(10_000).count
+      commits = g.log(10_000).execute
       g.revert(first_commit.sha)
-      assert_equal(commits + 1, g.log(10_000).count)
+      commits_after_revert = g.log(10_000).execute
+      assert_equal(commits.count + 1, commits_after_revert.count)
       assert(!File.exist?('test-file2'))
     end
   end
diff --git a/tests/units/test_log.rb b/tests/units/test_log.rb
index 75b3300b..f2219d78 100644
--- a/tests/units/test_log.rb
+++ b/tests/units/test_log.rb
@@ -11,103 +11,124 @@ def setup
   end
 
   def test_log_max_count_default
-    assert_equal(30, @git.log.size)
+    # Default max_count is 30
+    commits = @git.log.execute
+    assert_equal(30, commits.size)
   end
 
   # In these tests, note that @git.log(n) is equivalent to @git.log.max_count(n)
   def test_log_max_count_twenty
-    assert_equal(20, @git.log(20).size)
-    assert_equal(20, @git.log.max_count(20).size)
+    max_count = 20
+    commits = @git.log(max_count).execute
+    assert_equal(20, commits.size)
+    commits = @git.log.max_count(max_count).execute
+    assert_equal(20, commits.size)
   end
 
   def test_log_max_count_nil
-    assert_equal(72, @git.log(nil).size)
-    assert_equal(72, @git.log.max_count(nil).size)
+    # nil should return all commits
+    max_count = nil
+    commits = @git.log(max_count).execute
+    assert_equal(72, commits.size)
+    commits = @git.log.max_count(max_count).execute
+    assert_equal(72, commits.size)
   end
 
   def test_log_max_count_all
-    assert_equal(72, @git.log(:all).size)
-    assert_equal(72, @git.log.max_count(:all).size)
+    max_count = :all
+    commits = @git.log(max_count).execute
+    assert_equal(72, commits.size)
+    commits = @git.log.max_count(max_count).execute
+    assert_equal(72, commits.size)
   end
 
   # Note that @git.log.all does not control the number of commits returned. For that,
   # use @git.log.max_count(n)
   def test_log_all
-    assert_equal(72, @git.log(100).size)
-    assert_equal(76, @git.log(100).all.size)
+    commits = @git.log(100).execute
+    assert_equal(72, commits.size)
+    commits = @git.log(100).all.execute
+    assert_equal(76, commits.size)
   end
 
   def test_log_non_integer_count
-    assert_raises(ArgumentError) { @git.log('foo').size }
+    assert_raises(ArgumentError) do
+      commits = @git.log('foo').execute
+      commits.size
+    end
   end
 
   def test_get_first_and_last_entries
     log = @git.log
-    assert(log.first.is_a?(Git::Object::Commit))
-    assert_equal('46abbf07e3c564c723c7c039a43ab3a39e5d02dd', log.first.objectish)
+    commits = log.execute
+    assert(commits.first.is_a?(Git::Object::Commit))
+    assert_equal('46abbf07e3c564c723c7c039a43ab3a39e5d02dd', commits.first.objectish)
 
-    assert(log.last.is_a?(Git::Object::Commit))
-    assert_equal('b03003311ad3fa368b475df58390353868e13c91', log.last.objectish)
+    assert(commits.last.is_a?(Git::Object::Commit))
+    assert_equal('b03003311ad3fa368b475df58390353868e13c91', commits.last.objectish)
   end
 
   def test_get_log_entries
-    assert_equal(30, @git.log.size)
-    assert_equal(50, @git.log(50).size)
-    assert_equal(10, @git.log(10).size)
+    assert_equal(30, @git.log.execute.size)
+    assert_equal(50, @git.log(50).execute.size)
+    assert_equal(10, @git.log(10).execute.size)
   end
 
   def test_get_log_to_s
-    assert_equal(@git.log.to_s.split("\n").first, @git.log.first.sha)
+    commits = @git.log.execute
+    first_line = commits.to_s.split("\n").first
+    first_sha = commits.first.sha
+    assert_equal(first_line, first_sha)
   end
 
   def test_log_skip
-    three1 = @git.log(3).to_a[-1]
-    three2 = @git.log(2).skip(1).to_a[-1]
-    three3 = @git.log(1).skip(2).to_a[-1]
+    three1 = @git.log(3).execute.to_a[-1]
+    three2 = @git.log(2).skip(1).execute.to_a[-1]
+    three3 = @git.log(1).skip(2).execute.to_a[-1]
     assert_equal(three2.sha, three3.sha)
     assert_equal(three1.sha, three2.sha)
   end
 
   def test_get_log_since
-    l = @git.log.since('2 seconds ago')
-    assert_equal(0, l.size)
+    commits = @git.log.since('2 seconds ago').execute
+    assert_equal(0, commits.size)
 
-    l = @git.log.since("#{Date.today.year - 2006} years ago")
-    assert_equal(30, l.size)
+    commits = @git.log.since("#{Date.today.year - 2006} years ago").execute
+    assert_equal(30, commits.size)
   end
 
   def test_get_log_grep
-    l = @git.log.grep('search')
-    assert_equal(2, l.size)
+    commits = @git.log.grep('search').execute
+    assert_equal(2, commits.size)
   end
 
   def test_get_log_author
-    l = @git.log(5).author('chacon')
-    assert_equal(5, l.size)
-    l = @git.log(5).author('lazySusan')
-    assert_equal(0, l.size)
+    commits = @git.log(5).author('chacon').execute
+    assert_equal(5, commits.size)
+    commits = @git.log(5).author('lazySusan').execute
+    assert_equal(0, commits.size)
   end
 
   def test_get_log_since_file
-    l = @git.log.path('example.txt')
-    assert_equal(30, l.size)
+    commits = @git.log.path('example.txt').execute
+    assert_equal(30, commits.size)
 
-    l = @git.log.between('v2.5', 'test').path('example.txt')
-    assert_equal(1, l.size)
+    commits = @git.log.between('v2.5', 'test').path('example.txt').execute
+    assert_equal(1, commits.size)
   end
 
   def test_get_log_path
-    log = @git.log.path('example.txt')
-    assert_equal(30, log.size)
-    log = @git.log.path('example*')
-    assert_equal(30, log.size)
-    log = @git.log.path(['example.txt', 'scott/text.txt'])
-    assert_equal(30, log.size)
+    commits = @git.log.path('example.txt').execute
+    assert_equal(30, commits.size)
+    commits = @git.log.path('example*').execute
+    assert_equal(30, commits.size)
+    commits = @git.log.path(['example.txt', 'scott/text.txt']).execute
+    assert_equal(30, commits.size)
   end
 
   def test_log_file_noexist
     assert_raise Git::FailedError do
-      @git.log.object('no-exist.txt').size
+      @git.log.object('no-exist.txt').execute
     end
   end
 
@@ -117,20 +138,22 @@ def test_log_with_empty_commit_message
       expected_message = 'message'
       git.commit(expected_message, { allow_empty: true })
       git.commit('', { allow_empty: true, allow_empty_message: true })
-      log = git.log
-      assert_equal(2, log.to_a.size)
-      assert_equal('', log[0].message)
-      assert_equal(expected_message, log[1].message)
+      commits = git.log.execute
+      assert_equal(2, commits.size)
+      assert_equal('', commits[0].message)
+      assert_equal(expected_message, commits[1].message)
     end
   end
 
   def test_log_cherry
-    l = @git.log.between('master', 'cherry').cherry
-    assert_equal(1, l.size)
+    commits = @git.log.between('master', 'cherry').cherry.execute
+    assert_equal(1, commits.size)
   end
 
   def test_log_merges
     expected_command_line = ['log', '--no-color', '--max-count=30', '--pretty=raw', '--merges', { chdir: nil }]
-    assert_command_line_eq(expected_command_line) { |git| git.log.merges.size }
+    assert_command_line_eq(expected_command_line) do |git|
+      git.log.merges.execute
+    end
   end
 end
diff --git a/tests/units/test_merge.rb b/tests/units/test_merge.rb
index cd1e7554..30991d37 100644
--- a/tests/units/test_merge.rb
+++ b/tests/units/test_merge.rb
@@ -94,7 +94,8 @@ def test_no_ff_merge
       g.branch('new_branch2').checkout
       g.merge('new_branch', 'merge commit message') # ff merge
       assert(g.status['new_file_1']) # file has been merged in
-      assert_equal('first commit message', g.log.first.message) # merge commit message was ignored
+      commits = g.log.execute
+      assert_equal('first commit message', commits.first.message) # merge commit message was ignored
 
       g.branch('new_branch').in_branch('second commit message') do
         new_file('new_file_2', 'hello')
@@ -105,7 +106,8 @@ def test_no_ff_merge
       assert_equal('new_branch2', g.current_branch) # still in new_branch2 branch
       g.merge('new_branch', 'merge commit message', no_ff: true) # no-ff merge
       assert(g.status['new_file_2']) # file has been merged in
-      assert_equal('merge commit message', g.log.first.message)
+      commits = g.log.execute
+      assert_equal('merge commit message', commits.first.message)
     end
   end
 
diff --git a/tests/units/test_pull.rb b/tests/units/test_pull.rb
index 49770a7c..cdb6b768 100644
--- a/tests/units/test_pull.rb
+++ b/tests/units/test_pull.rb
@@ -44,9 +44,11 @@ class TestPull < Test::Unit::TestCase
 
       Dir.chdir('local') do
         git = Git.open('.')
-        assert_equal(1, git.log.size)
+        commits = git.log.execute
+        assert_equal(1, commits.size)
         assert_nothing_raised { git.pull }
-        assert_equal(2, git.log.size)
+        commits = git.log.execute
+        assert_equal(2, commits.size)
       end
     end
   end
@@ -72,9 +74,11 @@ class TestPull < Test::Unit::TestCase
 
       Dir.chdir('local') do
         git = Git.open('.')
-        assert_equal(1, git.log.size)
+        commits = git.log.execute
+        assert_equal(1, commits.size)
         assert_nothing_raised { git.pull('origin') }
-        assert_equal(2, git.log.size)
+        commits = git.log.execute
+        assert_equal(2, commits.size)
       end
     end
   end
@@ -104,9 +108,11 @@ class TestPull < Test::Unit::TestCase
 
       Dir.chdir('local') do
         git = Git.open('.')
-        assert_equal(1, git.log.size)
+        commits = git.log.execute
+        assert_equal(1, commits.size)
         assert_nothing_raised { git.pull('origin', 'feature1') }
-        assert_equal(3, git.log.size)
+        commits = git.log.execute
+        assert_equal(3, commits.size)
       end
     end
   end
diff --git a/tests/units/test_remotes.rb b/tests/units/test_remotes.rb
index cddc56cd..ed54536a 100644
--- a/tests/units/test_remotes.rb
+++ b/tests/units/test_remotes.rb
@@ -177,12 +177,14 @@ def test_fetch_ref_adds_ref_option
         new_file('test-file1', 'gonnaCommitYou')
         rem.add
         rem.commit('master commit 1')
-        first_commit_sha = rem.log.first.sha
+        commits = rem.log.execute
+        first_commit_sha = commits.first.sha
 
         new_file('test-file2', 'gonnaCommitYouToo')
         rem.add
         rem.commit('master commit 2')
-        second_commit_sha = rem.log.first.sha
+        commits = rem.log.execute
+        second_commit_sha = commits.first.sha
       end
 
       loc.chdir do
diff --git a/tests/units/test_windows_cmd_escaping.rb b/tests/units/test_windows_cmd_escaping.rb
index 85def7e3..dfb610bc 100644
--- a/tests/units/test_windows_cmd_escaping.rb
+++ b/tests/units/test_windows_cmd_escaping.rb
@@ -13,7 +13,7 @@ def test_commit_with_double_quote_in_commit_message
       git = Git.init('.')
       git.add
       git.commit(expected_commit_message)
-      commits = git.log(1)
+      commits = git.log(1).execute
       actual_commit_message = commits.first.message
       assert_equal(expected_commit_message, actual_commit_message)
     end