chore(internal): Truncate long commit body (#9278)

internal/gapicgen/git/git.go

@@ -24,6 +24,10 @@ import (
 	"github.com/go-git/go-git/v5"
 )
 
+const (
+	maxTruncatedTitleLen = 25
+)
+
 // ChangeInfo represents a change and its associated metadata.
 type ChangeInfo struct {
 	Body           string
@@ -35,6 +39,15 @@ type ChangeInfo struct {
 // the conventional commit footer pattern. This will allow these changes to be
 // parsed into the changelog.
 func FormatChanges(changes []*ChangeInfo, onlyGapicChanges bool) string {
+	formatted := truncateAndFormatChanges(changes, onlyGapicChanges, false)
+	if len(formatted) > maxChangesLen {
+		// Retry formatting by truncating
+		return truncateAndFormatChanges(changes, onlyGapicChanges, true)
+	}
+	return formatted
+}
+
+func truncateAndFormatChanges(changes []*ChangeInfo, onlyGapicChanges, truncate bool) string {
 	if len(changes) == 0 {
 		return ""
 	}
@@ -44,14 +57,26 @@ func FormatChanges(changes []*ChangeInfo, onlyGapicChanges bool) string {
 		if onlyGapicChanges {
 			continue
 		}
-		sb.WriteString(fmt.Sprintf("%s\n", c.Title))
+		title := c.Title
+		if truncate && len(title) > maxTruncatedTitleLen {
+			title = fmt.Sprintf("%v...", title[:maxTruncatedTitleLen])
+		}
+		sb.WriteString(fmt.Sprintf("%s\n", title))
 
 		// Format the commit body to conventional commit footer standards.
 		splitBody := strings.Split(c.Body, "\n")
 		for i := range splitBody {
 			splitBody[i] = fmt.Sprintf("  %s", splitBody[i])
 		}
 		body := strings.Join(splitBody, "\n")
+
+		if truncate {
+			startBody := strings.Index(body, "PiperOrigin-RevId")
+			if startBody != -1 {
+				body = fmt.Sprintf("  %s", body[startBody:])
+			}
+		}
+
 		sb.WriteString(fmt.Sprintf("%s\n\n", body))
 	}
 	// If the buffer is empty except for the "Changes:" text return an empty

internal/gapicgen/git/git_test.go

@@ -37,40 +37,59 @@ func TestParseConventionalCommitPkg(t *testing.T) {
 
 func TestFormatChanges(t *testing.T) {
 	tests := []struct {
-		name       string
-		changes    []*ChangeInfo
-		onlyGapics bool
-		want       string
+		name          string
+		changes       []*ChangeInfo
+		onlyGapics    bool
+		maxChangesLen int
+		want          string
 	}{
 		{
-			name:    "basic",
-			changes: []*ChangeInfo{{Title: "fix: foo", Body: "bar"}},
-			want:    "\nChanges:\n\nfix: foo\n  bar\n\n",
+			name:          "basic",
+			changes:       []*ChangeInfo{{Title: "fix: foo", Body: "bar"}},
+			maxChangesLen: maxChangesLen,
+			want:          "\nChanges:\n\nfix: foo\n  bar\n\n",
+		},
+		{
+			name:          "breaking change",
+			changes:       []*ChangeInfo{{Title: "feat!: breaking change", Body: "BREAKING CHANGE: The world is breaking."}},
+			maxChangesLen: maxChangesLen,
+			want:          "\nChanges:\n\nfeat!: breaking change\n  BREAKING CHANGE: The world is breaking.\n\n",
+		},
+		{
+			name:          "multi-lined body indented",
+			changes:       []*ChangeInfo{{Title: "fix: foo", Body: "bar\nbaz"}},
+			maxChangesLen: maxChangesLen,
+			want:          "\nChanges:\n\nfix: foo\n  bar\n  baz\n\n",
 		},
 		{
-			name:    "breaking change",
-			changes: []*ChangeInfo{{Title: "feat!: breaking change", Body: "BREAKING CHANGE: The world is breaking."}},
-			want:    "\nChanges:\n\nfeat!: breaking change\n  BREAKING CHANGE: The world is breaking.\n\n",
+			name:          "multi-lined body indented, multiple changes",
+			changes:       []*ChangeInfo{{Title: "fix: foo", Body: "bar\nbaz"}, {Title: "fix: baz", Body: "foo\nbar"}},
+			maxChangesLen: maxChangesLen,
+			want:          "\nChanges:\n\nfix: foo\n  bar\n  baz\n\nfix: baz\n  foo\n  bar\n\n",
 		},
 		{
-			name:    "multi-lined body indented",
-			changes: []*ChangeInfo{{Title: "fix: foo", Body: "bar\nbaz"}},
-			want:    "\nChanges:\n\nfix: foo\n  bar\n  baz\n\n",
+			name:          "no package, filtered",
+			changes:       []*ChangeInfo{{Title: "fix: foo", Body: "bar"}},
+			onlyGapics:    true,
+			maxChangesLen: maxChangesLen,
+			want:          "",
 		},
 		{
-			name:    "multi-lined body indented, multiple changes",
-			changes: []*ChangeInfo{{Title: "fix: foo", Body: "bar\nbaz"}, {Title: "fix: baz", Body: "foo\nbar"}},
-			want:    "\nChanges:\n\nfix: foo\n  bar\n  baz\n\nfix: baz\n  foo\n  bar\n\n",
+			name:          "truncate long title",
+			changes:       []*ChangeInfo{{Title: "fix: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod", Body: "tempor incididunt ut\nPiperOrigin-RevId: bar"}},
+			maxChangesLen: 100,
+			want:          "\nChanges:\n\nfix: Lorem ipsum dolor si...\n  PiperOrigin-RevId: bar\n\n",
 		},
 		{
-			name:       "no package, filtered",
-			changes:    []*ChangeInfo{{Title: "fix: foo", Body: "bar"}},
-			onlyGapics: true,
-			want:       "",
+			name:          "no truncate short title",
+			changes:       []*ChangeInfo{{Title: "fix: Lorem ipsum dolor", Body: "tempor incididunt ut\n PiperOrigin-RevId: bar"}},
+			maxChangesLen: 50,
+			want:          "\nChanges:\n\nfix: Lorem ipsum dolor\n  PiperOrigin-RevId: bar\n\n",
 		},
 	}
 
 	for _, tc := range tests {
+		maxChangesLen = tc.maxChangesLen
 		t.Run(tc.name, func(t *testing.T) {
 			if got := FormatChanges(tc.changes, tc.onlyGapics); got != tc.want {
 				t.Errorf("FormatChanges() = %q, want %q", got, tc.want)

internal/gapicgen/git/github.go

@@ -47,9 +47,13 @@ If you have been assigned to review this PR, please:
 - Approve and submit this PR if you believe it's ready to ship. That will prompt
 genbot to assign reviewers to the google-cloud-go PR.
 `
+	maxCommitBodyLen = 65536
 )
 
-var conventionalCommitScopeRe = regexp.MustCompile(`.*\((.*)\): .*`)
+var (
+	conventionalCommitScopeRe = regexp.MustCompile(`.*\((.*)\): .*`)
+	maxChangesLen             = maxCommitBodyLen - len(genprotoCommitBody)
+)
 
 // PullRequest represents a GitHub pull request.
 type PullRequest struct {