git_extensions: move commit_message from utils/git

Library/Homebrew/dev-cmd/pr-pull.rb

@@ -89,7 +89,7 @@ module Homebrew
   end
 
   def signoff!(path, pr: nil, dry_run: false)
-    subject, body, trailers = separate_commit_message(Utils::Git.commit_message(path))
+    subject, body, trailers = separate_commit_message(path.git_commit_message)
 
     if pr
       # This is a tap pull request and approving reviewers should also sign-off.
@@ -156,7 +156,7 @@ module Homebrew
     new_formula = Utils::Git.file_at_commit(path, file, "HEAD")
 
     bump_subject = determine_bump_subject(old_formula, new_formula, formula_file, reason: reason).strip
-    subject, body, trailers = separate_commit_message(Utils::Git.commit_message(path))
+    subject, body, trailers = separate_commit_message(path.git_commit_message)
 
     if subject != bump_subject && !subject.start_with?("#{formula_name}:")
       safe_system("git", "-C", path, "commit", "--amend", "-q",
@@ -181,7 +181,7 @@ module Homebrew
     messages = []
     trailers = []
     commits.each do |commit|
-      subject, body, trailer = separate_commit_message(Utils::Git.commit_message(path, commit))
+      subject, body, trailer = separate_commit_message(path.git_commit_message(commit))
       body = body.lines.map { |line| "  #{line.strip}" }.join("\n")
       messages << "* #{subject}\n#{body}".strip
       trailers << trailer

Library/Homebrew/extend/git_repository.rb

@@ -85,4 +85,12 @@ module GitRepositoryExtension
 
     Utils.popen_read("git", "show", "-s", "--format=%cd", "--date=short", "HEAD", chdir: self).chomp.presence
   end
+
+  # Gets the full commit message of the specified commit, or of the HEAD commit if unspecified.
+  sig { params(commit: String).returns(T.nilable(String)) }
+  def git_commit_message(commit = "HEAD")
+    return unless git? && Utils::Git.available?
+
+    Utils.popen_read("git", "log", "-1", "--pretty=%B", commit, "--", chdir: self, err: :out).strip.presence
+  end
 end

Library/Homebrew/test/dev-cmd/pr-pull_spec.rb

@@ -38,7 +38,7 @@ describe Homebrew do
     EOS
   end
   let(:formula_file) { path/"Formula/foo.rb" }
-  let(:path) { Tap::TAP_DIRECTORY/"homebrew/homebrew-foo" }
+  let(:path) { (Tap::TAP_DIRECTORY/"homebrew/homebrew-foo").extend(GitRepositoryExtension) }
 
   describe "Homebrew.pr_pull_args" do
     it_behaves_like "parseable arguments"
@@ -59,8 +59,8 @@ describe Homebrew do
         File.open(formula_file, "w") { |f| f.write(formula_version) }
         safe_system Utils::Git.git, "commit", formula_file, "-m", "version", "--author=#{secondary_author}"
         described_class.autosquash!(original_hash, path: path)
-        expect(Utils::Git.commit_message(path)).to include("foo 2.0")
-        expect(Utils::Git.commit_message(path)).to include("Co-authored-by: #{secondary_author}")
+        expect(path.git_commit_message).to include("foo 2.0")
+        expect(path.git_commit_message).to include("Co-authored-by: #{secondary_author}")
       end
     end
   end
@@ -75,7 +75,7 @@ describe Homebrew do
         safe_system Utils::Git.git, "commit", "-m", "foo 1.0 (new formula)"
       end
       described_class.signoff!(path)
-      expect(Utils::Git.commit_message(path)).to include("Signed-off-by:")
+      expect(path.git_commit_message).to include("Signed-off-by:")
     end
   end
 

Library/Homebrew/test/utils/git_spec.rb

@@ -52,19 +52,6 @@ describe Utils::Git do
   let(:files_hash2) { [@h2[0..6], ["README.md"]] }
   let(:cherry_pick_commit) { @cherry_pick_commit[0..6] }
 
-  describe "#commit_message" do
-    it "returns the commit message" do
-      expect(described_class.commit_message(HOMEBREW_CACHE, file_hash1)).to eq("File added")
-      expect(described_class.commit_message(HOMEBREW_CACHE, file_hash2)).to eq("written to File")
-    end
-
-    it "errors when commit doesn't exist" do
-      expect {
-        described_class.commit_message(HOMEBREW_CACHE, "bad_refspec")
-      }.to raise_error(ErrorDuringExecution, /bad revision/)
-    end
-  end
-
   describe "#cherry_pick!" do
     it "can cherry pick a commit" do
       expect(described_class.cherry_pick!(HOMEBREW_CACHE, cherry_pick_commit)).to be_truthy

Library/Homebrew/utils/git.rb

@@ -89,8 +89,9 @@ module Utils
     end
 
     def commit_message(repo, commit = nil)
+      odeprecated "Utils::Git.commit_message(repo)", "Pathname(repo).git_commit_message"
       commit ||= "HEAD"
-      Utils.safe_popen_read(git, "-C", repo, "log", "-1", "--pretty=%B", commit, "--", err: :out).strip
+      Pathname(repo).extend(GitRepositoryExtension).git_commit_message(commit)
     end
 
     def ensure_installed!