refactor: decouple git.Repository(ctx) from git.Commit & git.Tree (#38464)

1. Storing "ctx" in a long-living object is wrong
2. Make the commit & tree cacheable (for the future performance
optimization)
3. Also fix some bad designs like `// FIXME: bad design, this field can
be nil if the commit is from "last commit cache"`

ref:
* #33893

services/actions/notifier_helper.go

@@ -185,7 +185,7 @@ func notify(ctx context.Context, input *notifyInput) error {
 	var detectedWorkflows []*actions_module.DetectedWorkflow
 	var filteredWorkflows []*actions_module.DetectedWorkflow
 	actionsConfig := input.Repo.MustGetUnit(ctx, unit_model.TypeActions).ActionsConfig()
-	workflows, schedules, filtered, err := actions_module.DetectWorkflows(gitRepo, commit,
+	workflows, schedules, filtered, err := actions_module.DetectWorkflows(ctx, gitRepo, commit,
 		input.Event,
 		input.Payload,
 		shouldDetectSchedules,
@@ -231,7 +231,7 @@ func notify(ctx context.Context, input *notifyInput) error {
 		if err != nil {
 			return fmt.Errorf("gitRepo.GetCommit: %w", err)
 		}
-		baseWorkflows, _, baseFiltered, err := actions_module.DetectWorkflows(gitRepo, baseCommit, input.Event, input.Payload, false)
+		baseWorkflows, _, baseFiltered, err := actions_module.DetectWorkflows(ctx, gitRepo, baseCommit, input.Event, input.Payload, false)
 		if err != nil {
 			return fmt.Errorf("DetectWorkflows: %w", err)
 		}
@@ -602,7 +602,7 @@ func DetectAndHandleSchedules(ctx context.Context, repo *repo_model.Repository)
 	if err != nil {
 		return fmt.Errorf("gitRepo.GetCommit: %w", err)
 	}
-	scheduleWorkflows, err := actions_module.DetectScheduledWorkflows(gitRepo, commit)
+	scheduleWorkflows, err := actions_module.DetectScheduledWorkflows(ctx, gitRepo, commit)
 	if err != nil {
 		return fmt.Errorf("detect schedule workflows: %w", err)
 	}
@@ -743,6 +743,7 @@ func detectScopedWorkflowsForSource(
 	sourceRepo *repo_model.Repository,
 ) (sourceCommitSHA string, detected, filtered []*actions_module.DetectedWorkflow, err error) {
 	// scoped workflow content is always taken from the source repo's default branch; the parse is cached per (source, default-branch SHA) and reused across consuming repos/events
+
 	sourceCommitSHA, parsed, err := LoadParsedScopedWorkflows(ctx, sourceRepo)
 	if err != nil {
 		return "", nil, nil, err

services/actions/reusable_workflow.go

@@ -89,7 +89,7 @@ func readWorkflowFromRepo(ctx context.Context, repo *repo_model.Repository, refO
 	if err != nil {
 		return nil, "", fmt.Errorf("get commit %q in %s: %w", refOrSHA, repo.FullName(), err)
 	}
-	str, err := commit.GetFileContent(path, 1024*1024)
+	str, err := commit.GetFileContent(ctx, gitRepo, path, 1024*1024)
 	if err != nil {
 		return nil, "", fmt.Errorf("read %s@%s:%s: %w", repo.FullName(), refOrSHA, path, err)
 	}

services/actions/scoped_workflow_cache.go

@@ -60,7 +60,7 @@ func LoadParsedScopedWorkflows(ctx context.Context, sourceRepo *repo_model.Repos
 	if err != nil {
 		return "", nil, fmt.Errorf("get source commit %s: %w", sha, err)
 	}
-	parsed, err = actions_module.ParseScopedWorkflows(sourceCommit)
+	parsed, err = actions_module.ParseScopedWorkflows(ctx, sourceGitRepo, sourceCommit)
 	if err != nil {
 		return "", nil, err
 	}

services/actions/workflow.go

@@ -119,7 +119,7 @@ func DispatchActionWorkflow(ctx reqctx.RequestContext, doer *user_model.User, re
 	}
 
 	// resolve the workflow content and record its source on the run (scoped runs read from the source repo)
-	content, err := resolveDispatchWorkflowContent(ctx, repo, runTargetCommit, workflowID, scopedWorkflowSourceRepoID, isScoped, run)
+	content, err := resolveDispatchWorkflowContent(ctx, repo, gitRepo, runTargetCommit, workflowID, scopedWorkflowSourceRepoID, isScoped, run)
 	if err != nil {
 		return 0, err
 	}
@@ -172,18 +172,18 @@ func DispatchActionWorkflow(ctx reqctx.RequestContext, doer *user_model.User, re
 // resolveDispatchWorkflowContent returns the YAML for a dispatched workflow and records its source on the run.
 //   - Repo-level: from the consumer's runTargetCommit.
 //   - Scoped: from the source repo's default branch.
-func resolveDispatchWorkflowContent(ctx reqctx.RequestContext, repo *repo_model.Repository, runTargetCommit *git.Commit, workflowID string, sourceRepoID int64, isScoped bool, run *actions_model.ActionRun) ([]byte, error) {
+func resolveDispatchWorkflowContent(ctx reqctx.RequestContext, repo *repo_model.Repository, gitRepo *git.Repository, runTargetCommit *git.Commit, workflowID string, sourceRepoID int64, isScoped bool, run *actions_model.ActionRun) ([]byte, error) {
 	if isScoped {
 		return resolveScopedDispatchContent(ctx, repo, sourceRepoID, workflowID, run)
 	}
 
-	_, entries, err := actions.ListWorkflows(runTargetCommit)
+	_, entries, err := actions.ListWorkflows(ctx, gitRepo, runTargetCommit)
 	if err != nil {
 		return nil, err
 	}
 	for _, e := range entries {
 		if e.Name() == workflowID {
-			return actions.GetContentFromEntry(e)
+			return actions.GetContentFromEntry(gitRepo, e)
 		}
 	}
 	return nil, util.ErrorWrapTranslatable(