use PR template when opening PRs (#77)

* use pr template when opening prs

* add a helper to clearly distinguish between filesystem errors and actual test failures

Author: skarim

cmd/link.go

@@ -9,6 +9,7 @@ import (
 	"github.com/github/gh-stack/internal/config"
 	"github.com/github/gh-stack/internal/git"
 	"github.com/github/gh-stack/internal/github"
+	"github.com/github/gh-stack/internal/pr"
 	"github.com/spf13/cobra"
 )
 
@@ -109,6 +110,12 @@ func runLink(cfg *config.Config, opts *linkOptions, args []string) error {
 		}
 	}
 
+	// Look up the repository's PR template (best-effort; skip if not in a repo).
+	var templateContent string
+	if repoRoot, tlErr := git.RootDir(); tlErr == nil {
+		templateContent = pr.FindTemplate(repoRoot)
+	}
+
 	// Phase 4: Create PRs for branches that don't have one yet
 	needsCreation := 0
 	for _, r := range found {
@@ -119,7 +126,7 @@ func runLink(cfg *config.Config, opts *linkOptions, args []string) error {
 	if needsCreation > 0 {
 		cfg.Printf("Creating %d %s...", needsCreation, plural(needsCreation, "PR", "PRs"))
 	}
-	resolved, err := createMissingPRs(cfg, client, opts, args, found)
+	resolved, err := createMissingPRs(cfg, client, opts, args, found, templateContent)
 	if err != nil {
 		return err
 	}
@@ -303,7 +310,7 @@ func prevalidateStack(cfg *config.Config, stacks []github.RemoteStack, knownPRNu
 
 // createMissingPRs creates PRs for branches that don't have one yet.
 // Returns the fully resolved list with all branches mapped to PRs.
-func createMissingPRs(cfg *config.Config, client github.ClientOps, opts *linkOptions, args []string, found []*resolvedArg) ([]resolvedArg, error) {
+func createMissingPRs(cfg *config.Config, client github.ClientOps, opts *linkOptions, args []string, found []*resolvedArg, templateContent string) ([]resolvedArg, error) {
 	resolved := make([]resolvedArg, len(args))
 
 	for i, arg := range args {
@@ -319,7 +326,7 @@ func createMissingPRs(cfg *config.Config, client github.ClientOps, opts *linkOpt
 		}
 
 		title := humanize(arg)
-		body := generatePRBody("")
+		body := generatePRBody("", templateContent)
 
 		newPR, err := client.CreatePR(baseBranch, arg, title, body, !opts.open)
 		if err != nil {

cmd/link_test.go

@@ -3,6 +3,8 @@ package cmd
 import (
 	"fmt"
 	"io"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/cli/go-gh/v2/pkg/api"
@@ -1203,3 +1205,104 @@ func TestLink_SkipsBaseFix_ForNewlyCreatedPRs(t *testing.T) {
 
 // Silence "imported and not used" for fmt in case test helpers use it.
 var _ = fmt.Sprintf
+
+func TestLink_BranchNames_UsesPRTemplate(t *testing.T) {
+	tmpDir := t.TempDir()
+	ghDir := filepath.Join(tmpDir, ".github")
+	require.NoError(t, os.MkdirAll(ghDir, 0o755))
+	require.NoError(t, os.WriteFile(
+		filepath.Join(ghDir, "pull_request_template.md"),
+		[]byte("## Summary\n\nDescribe your changes."),
+		0o644,
+	))
+
+	mock := newLinkGitMock("feat-a", "feat-b")
+	mock.RootDirFn = func() (string, error) { return tmpDir, nil }
+	restore := git.SetOps(mock)
+	defer restore()
+
+	var capturedBody string
+	cfg, _, errR := config.NewTestConfig()
+	cfg.GitHubClientOverride = &github.MockClient{
+		FindPRForBranchFn: func(string) (*github.PullRequest, error) {
+			return nil, nil // No existing PRs
+		},
+		CreatePRFn: func(base, head, title, body string, draft bool) (*github.PullRequest, error) {
+			capturedBody = body
+			return &github.PullRequest{
+				Number: 1, HeadRefName: head, BaseRefName: base,
+				URL: "https://github.com/o/r/pull/1",
+			}, nil
+		},
+		ListStacksFn: func() ([]github.RemoteStack, error) {
+			return []github.RemoteStack{}, nil
+		},
+		CreateStackFn: func([]int) (int, error) { return 42, nil },
+	}
+
+	cmd := LinkCmd(cfg)
+	cmd.SetArgs([]string{"feat-a", "feat-b"})
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+	err := cmd.Execute()
+
+	cfg.Err.Close()
+	_, _ = io.ReadAll(errR)
+
+	assert.NoError(t, err)
+	assert.Contains(t, capturedBody, "## Summary")
+	assert.Contains(t, capturedBody, "Describe your changes.")
+	assert.NotContains(t, capturedBody, "GitHub Stacks CLI", "footer should not be present when template is used")
+}
+
+func TestLink_PRNumbers_NoTemplateUsesFooter(t *testing.T) {
+	// When using PR numbers (no local repo context), no template is found
+	// and the footer should be present for newly created PRs.
+	mock := &git.MockOps{
+		RootDirFn: func() (string, error) {
+			return "", fmt.Errorf("not in a git repo")
+		},
+	}
+	restore := git.SetOps(mock)
+	defer restore()
+
+	var capturedBody string
+	cfg, _, errR := config.NewTestConfig()
+	cfg.GitHubClientOverride = &github.MockClient{
+		FindPRByNumberFn: func(n int) (*github.PullRequest, error) {
+			if n == 10 {
+				return &github.PullRequest{
+					Number: 10, HeadRefName: "feat-a", BaseRefName: "main",
+					URL: "https://github.com/o/r/pull/10",
+				}, nil
+			}
+			return nil, nil // PR 20 doesn't exist → will create
+		},
+		FindPRForBranchFn: func(branch string) (*github.PullRequest, error) {
+			return nil, nil
+		},
+		CreatePRFn: func(base, head, title, body string, draft bool) (*github.PullRequest, error) {
+			capturedBody = body
+			return &github.PullRequest{
+				Number: 20, HeadRefName: head, BaseRefName: base,
+				URL: "https://github.com/o/r/pull/20",
+			}, nil
+		},
+		ListStacksFn: func() ([]github.RemoteStack, error) {
+			return []github.RemoteStack{}, nil
+		},
+		CreateStackFn: func([]int) (int, error) { return 42, nil },
+	}
+
+	cmd := LinkCmd(cfg)
+	cmd.SetArgs([]string{"10", "20"})
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+	err := cmd.Execute()
+
+	cfg.Err.Close()
+	_, _ = io.ReadAll(errR)
+
+	assert.NoError(t, err)
+	assert.Contains(t, capturedBody, "GitHub Stacks CLI", "footer should be present when no template")
+}

cmd/submit.go

@@ -12,6 +12,7 @@ import (
 	"github.com/github/gh-stack/internal/git"
 	"github.com/github/gh-stack/internal/github"
 	"github.com/github/gh-stack/internal/modify"
+	"github.com/github/gh-stack/internal/pr"
 	"github.com/github/gh-stack/internal/stack"
 	"github.com/spf13/cobra"
 )
@@ -148,6 +149,12 @@ func runSubmit(cfg *config.Config, opts *submitOptions) error {
 	// remote yet.
 	_ = git.FetchBranches(remote, activeBranches)
 
+	// Look up the repository's PR template once before creating any PRs.
+	var templateContent string
+	if repoRoot, err := git.RootDir(); err == nil {
+		templateContent = pr.FindTemplate(repoRoot)
+	}
+
 	// Push each branch and create/update its PR in stack order (bottom to top).
 	// Sequential pushing ensures each branch's base is up-to-date on the
 	// remote before the next branch is pushed, preventing race conditions.
@@ -165,7 +172,7 @@ func runSubmit(cfg *config.Config, opts *submitOptions) error {
 
 		// Find or create PR, and fix base if needed
 		baseBranch := s.ActiveBaseBranch(b.Branch)
-		if err := ensurePR(cfg, client, s, i, baseBranch, opts); err != nil {
+		if err := ensurePR(cfg, client, s, i, baseBranch, opts, templateContent); err != nil {
 			if errors.Is(err, errInterrupt) {
 				printInterrupt(cfg)
 				return ErrSilent
@@ -195,7 +202,7 @@ func runSubmit(cfg *config.Config, opts *submitOptions) error {
 // ensurePR finds or creates a PR for the branch at index i, and updates
 // its base branch if needed. This is the single place where PR state is
 // reconciled during submit.
-func ensurePR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int, baseBranch string, opts *submitOptions) error {
+func ensurePR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int, baseBranch string, opts *submitOptions, templateContent string) error {
 	b := s.Branches[i]
 
 	pr, err := client.FindPRForBranch(b.Branch)
@@ -205,7 +212,7 @@ func ensurePR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int
 	}
 
 	if pr == nil {
-		return createPR(cfg, client, s, i, baseBranch, opts)
+		return createPR(cfg, client, s, i, baseBranch, opts, templateContent)
 	}
 
 	// PR exists — record it and fix base if needed.
@@ -250,7 +257,7 @@ func ensurePR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int
 }
 
 // createPR creates a new PR for the branch at index i.
-func createPR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int, baseBranch string, opts *submitOptions) error {
+func createPR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int, baseBranch string, opts *submitOptions, templateContent string) error {
 	b := s.Branches[i]
 
 	title, commitBody := defaultPRTitleBody(baseBranch, b.Branch)
@@ -272,7 +279,7 @@ func createPR(cfg *config.Config, client github.ClientOps, s *stack.Stack, i int
 	if title != originalTitle && commitBody != "" {
 		prBody = originalTitle + "\n\n" + commitBody
 	}
-	body := generatePRBody(prBody)
+	body := generatePRBody(prBody, templateContent)
 
 	newPR, createErr := client.CreatePR(baseBranch, b.Branch, title, body, !opts.open)
 	if createErr != nil {
@@ -299,9 +306,14 @@ func defaultPRTitleBody(base, head string) (string, string) {
 	return humanize(head), ""
 }
 
-// generatePRBody builds a PR description from the commit body (if any)
-// and a footer linking to the CLI and feedback form.
-func generatePRBody(commitBody string) string {
+// generatePRBody builds a PR description. When a templateContent is provided,
+// it is used as the body and the attribution footer is omitted. Otherwise the
+// body is built from the commit body with a footer linking to the CLI.
+func generatePRBody(commitBody string, templateContent string) string {
+	if templateContent != "" {
+		return templateContent
+	}
+
 	var parts []string
 
 	if commitBody != "" {