submit: Invalidate template cache if origin/main is updated (#370)

We calculate the template cache key based on the hashes of the files
inside the locations in the repository where tempates are stored,
but we check their state at `$trunk` instead of `$remote/$trunk`.

This results in the cache not being invalidated
if the remote has been updated and fetched, but the local ref is behind.

Ref #369

.changes/unreleased/Fixed-20240829-202317.yaml

@@ -0,0 +1,3 @@
+kind: Fixed
+body: 'submit: Fix outdated PR template being used when trunk is behind its remote ref.'
+time: 2024-08-29T20:23:17.238952-07:00

branch_submit.go

@@ -295,6 +295,7 @@ func (cmd *branchSubmitCmd) run(
 				svc,
 				store,
 				repo,
+				remote,
 				remoteRepo,
 				branch.Base,
 			)
@@ -558,6 +559,7 @@ func (cmd *branchSubmitCmd) preparePublish(
 	svc *spice.Service,
 	store *state.Store,
 	repo *git.Repository,
+	remoteName string,
 	remoteRepo forge.Repository,
 	baseBranch string,
 ) (*preparedBranch, error) {
@@ -569,7 +571,7 @@ func (cmd *branchSubmitCmd) preparePublish(
 		ctx, cancel := context.WithTimeout(ctx, time.Second)
 		defer cancel()
 
-		templates, err := svc.ListChangeTemplates(ctx, remoteRepo)
+		templates, err := svc.ListChangeTemplates(ctx, remoteName, remoteRepo)
 		if err != nil {
 			log.Warn("Could not list change templates", "error", err)
 			templates = nil

internal/spice/template.go

@@ -14,7 +14,11 @@ import (
 
 // ListChangeTemplates returns the Change templates defined in the repository.
 // For GitHub, these are PR templates.
-func (s *Service) ListChangeTemplates(ctx context.Context, fr forge.Repository) ([]*forge.ChangeTemplate, error) {
+func (s *Service) ListChangeTemplates(
+	ctx context.Context,
+	remoteName string,
+	fr forge.Repository,
+) ([]*forge.ChangeTemplate, error) {
 	// TODO: Should Repo be injected?
 	templatePaths := fr.Forge().ChangeTemplatePaths()
 	sort.Strings(templatePaths)
@@ -26,7 +30,7 @@ func (s *Service) ListChangeTemplates(ctx context.Context, fr forge.Repository)
 	keyHash := sha256.New()
 	_, _ = fmt.Fprintf(keyHash, "%d\n", len(templatePaths))
 	for _, path := range templatePaths {
-		h, err := s.repo.HashAt(ctx, s.store.Trunk(), path)
+		h, err := s.repo.HashAt(ctx, remoteName+"/"+s.store.Trunk(), path)
 		if err != nil {
 			if errors.Is(err, git.ErrNotExist) {
 				_, _ = fmt.Fprintf(keyHash, "0\n")

testdata/script/issue369_branch_submit_pr_template_cache_remote_update.txt

@@ -0,0 +1,94 @@
+# 'branch submit' invalidates template cache
+# if remote has an update even if the local branch is behind.
+#
+# https://github.com/abhinav/git-spice/issues/369
+
+as 'Test <[email protected]>'
+at '2024-08-29T20:21:22Z'
+
+# setup
+cd repo
+git init
+git add .shamhub
+git commit -m 'Initial commit'
+
+# set up a fake remote
+shamhub init
+shamhub new origin alice/example.git
+shamhub register alice
+git push origin main
+
+env SHAMHUB_USERNAME=alice
+gs auth login
+
+# Submit a PR with the first template.
+git add feature1.txt
+gs bc -m feature1
+gs branch submit --fill
+
+# Update the template remotely
+cd $WORK
+shamhub clone alice/example.git fork
+cd fork
+mv $WORK/extra/CHANGE_TEMPLATE.md .shamhub/CHANGE_TEMPLATE.md
+git add .shamhub/CHANGE_TEMPLATE.md
+git commit -m 'Change the template'
+git push origin main
+
+# Update origin/main but not main
+cd $WORK/repo
+git fetch
+
+# Create a new PR with the new template.
+git add feature2.txt
+gs bc -m feature2
+gs branch submit --fill
+
+shamhub dump changes
+cmpenv stdout $WORK/golden/pulls.json
+
+-- repo/.shamhub/CHANGE_TEMPLATE.md --
+This is the first template.
+
+-- extra/CHANGE_TEMPLATE.md --
+This is the second template.
+
+-- repo/feature1.txt --
+feature 1
+
+-- repo/feature2.txt --
+feature 2
+
+-- golden/pulls.json --
+[
+  {
+    "number": 1,
+    "html_url": "$SHAMHUB_URL/alice/example/change/1",
+    "state": "open",
+    "title": "feature1",
+    "body": "\n\nThis is the first template.\n",
+    "base": {
+      "ref": "main",
+      "sha": "a272771860a18e5e7ee7ef971e749c27574826fd"
+    },
+    "head": {
+      "ref": "feature1",
+      "sha": "68b4a07edfb5682221a0207c31de4a99c7dd0d3d"
+    }
+  },
+  {
+    "number": 2,
+    "html_url": "$SHAMHUB_URL/alice/example/change/2",
+    "state": "open",
+    "title": "feature2",
+    "body": "\n\nThis is the second template.\n",
+    "base": {
+      "ref": "feature1",
+      "sha": "68b4a07edfb5682221a0207c31de4a99c7dd0d3d"
+    },
+    "head": {
+      "ref": "feature2",
+      "sha": "bfe1a896f408b265d43552a2d450618a181e8f8b"
+    }
+  }
+]