fix(discussion/shared): error on out-of-range discussion number in URL

The discussion URL pattern captures one or more digits, which can exceed the int32 range. The parse error from strconv.ParseInt was previously discarded, silently clamping the number. Return an explicit error instead, and cover it with tests in both URL parsing functions. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
babakks · Jun 10, 2026 · Jun 1, 2026 · Jun 1, 2026 · Jun 1, 2026 · Jun 1, 2026
commit d63ab8ddd8696194f3fd49a726eb6d60dd3cdfa5
@@ -38,7 +38,11 @@ func ParseDiscussionArg(arg string) (int32, ghrepo.Interface, error) {
 		return 0, nil, fmt.Errorf("invalid discussion URL: %q", arg)
 	}
 
-	num, _ := strconv.ParseInt(m[3], 10, 32)
+	num, err := strconv.ParseInt(m[3], 10, 32)
+	if err != nil {
+		return 0, nil, fmt.Errorf("invalid discussion number in URL: %q", m[3])
+	}
+
 	repo := ghrepo.NewWithHost(m[1], m[2], u.Hostname())
 	return int32(num), repo, nil
 }
@@ -84,7 +88,10 @@ func ParseDiscussionOrCommentArg(arg string) (*ParsedDiscussionOrCommentArg, err
 		return nil, fmt.Errorf("invalid discussion URL: %q", arg)
 	}
 
-	num, _ := strconv.ParseInt(m[3], 10, 32)
+	num, err := strconv.ParseInt(m[3], 10, 32)
+	if err != nil {
+		return nil, fmt.Errorf("invalid discussion number in URL: %q", m[3])
+	}
 	repo := ghrepo.NewWithHost(m[1], m[2], u.Hostname())
 
 	if fragment := u.Fragment; strings.HasPrefix(fragment, "discussioncomment-") {

@@ -52,6 +52,11 @@ func TestParseDiscussionArg(t *testing.T) {
 			arg:     "https://github.com/owner/repo/discussions/",
 			wantErr: `invalid discussion URL: "https://github.com/owner/repo/discussions/"`,
 		},
+		{
+			name:    "URL with overflowing number",
+			arg:     "https://github.com/owner/repo/discussions/99999999999999999999",
+			wantErr: `invalid discussion number in URL: "99999999999999999999"`,
+		},
 		{
 			name:    "zero",
 			arg:     "0",
@@ -166,6 +171,11 @@ func TestParseDiscussionOrCommentArg(t *testing.T) {
 			arg:     "https://github.com/owner/repo/discussions/",
 			wantErr: `invalid discussion URL: "https://github.com/owner/repo/discussions/"`,
 		},
+		{
+			name:    "URL with overflowing number",
+			arg:     "https://github.com/owner/repo/discussions/99999999999999999999",
+			wantErr: `invalid discussion number in URL: "99999999999999999999"`,
+		},
 		{
 			name:    "comment URL with invalid fragment",
 			arg:     "https://github.com/owner/repo/discussions/5#discussioncomment-abc",