Treat no-op git commit (nothing to commit) as a skip, not a failure

lib/git_client.rb

@@ -43,7 +43,9 @@ def commit_changes(message:)
       @repo.commit(message)
       true
     rescue Git::FailedError => e
-      return false if e.result.stderr.to_s.include?("nothing to commit")
+      # git prints "nothing to commit" to stdout; check both streams so a
+      # no-op pin is treated as a skip rather than a hard failure.
+      return false if "#{e.result.stdout} #{e.result.stderr}".include?("nothing to commit")
       raise
     end
 

test/git_client_test.rb

@@ -61,6 +61,17 @@ def test_commit_changes_returns_false_when_nothing_to_commit
     assert_equal false, @client.commit_changes(message: "irrelevant")
   end
 
+  def test_commit_changes_returns_false_when_nothing_to_commit_on_stdout
+    @repo.expect(:add, nil, [["config/importmap.rb", "vendor/javascript"]])
+    @repo.expect(:config, nil, ["user.name", AUTHOR_NAME])
+    @repo.expect(:config, nil, ["user.email", AUTHOR_EMAIL])
+    @repo.expect(:commit, nil) do |_msg, **_opts|
+      raise git_failed_error("", "nothing to commit, working tree clean")
+    end
+
+    assert_equal false, @client.commit_changes(message: "irrelevant")
+  end
+
   def test_commit_changes_re_raises_unexpected_git_errors
     @repo.expect(:add, nil, [["config/importmap.rb", "vendor/javascript"]])
     @repo.expect(:config, nil, ["user.name", AUTHOR_NAME])
@@ -90,9 +101,9 @@ def test_push_with_force
 
   # Git::FailedError wraps a Git::CommandLineResult which needs a status
   # object. We build the minimum required for e.result.stderr to work.
-  def git_failed_error(stderr)
+  def git_failed_error(stderr, stdout = "")
     fake_status = Struct.new(:exitstatus, :pid) { def to_s = "pid #{pid} exit #{exitstatus}" }.new(1, 0)
-    result = Git::CommandLineResult.new(["git", "commit"], fake_status, "", stderr)
+    result = Git::CommandLineResult.new(["git", "commit"], fake_status, stdout, stderr)
     Git::FailedError.new(result)
   end
 end