fix: encode branch names in GitHub links (#1713)

* fix: encode branch names in GitHub links

* style: format branch URL helper

src/entrypoints/update-comment-link.ts

@@ -16,6 +16,7 @@ import type { ParsedGitHubContext } from "../github/context";
 import { GITHUB_SERVER_URL } from "../github/api/config";
 import { checkAndCommitOrDeleteBranch } from "../github/operations/branch-cleanup";
 import { updateClaudeComment } from "../github/operations/comments/update-claude-comment";
+import { encodeBranchNameForUrl } from "../github/operations/comments/common";
 
 export type UpdateCommentLinkParams = {
   commentId: number;
@@ -159,7 +160,7 @@ export async function updateCommentLink(
           const prBody = encodeURIComponent(
             `This PR addresses ${entityType.toLowerCase()} #${context.entityNumber}\n\nGenerated with [Claude Code](https://claude.ai/code)`,
           );
-          const prUrl = `${serverUrl}/${owner}/${repo}/compare/${baseBranch}...${claudeBranch}?quick_pull=1&title=${prTitle}&body=${prBody}`;
+          const prUrl = `${serverUrl}/${owner}/${repo}/compare/${encodeBranchNameForUrl(baseBranch)}...${encodeBranchNameForUrl(claudeBranch)}?quick_pull=1&title=${prTitle}&body=${prBody}`;
           prLink = `\n[Create a PR](${prUrl})`;
         }
       } catch (error) {

src/github/operations/branch-cleanup.ts

@@ -1,5 +1,6 @@
 import type { Octokits } from "../api/client";
 import { GITHUB_SERVER_URL } from "../api/config";
+import { encodeBranchNameForUrl } from "./comments/common";
 import { $ } from "bun";
 
 export async function checkAndCommitOrDeleteBranch(
@@ -106,7 +107,7 @@ export async function checkAndCommitOrDeleteBranch(
               );
 
               // Set branch link since we now have commits
-              const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${claudeBranch}`;
+              const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${encodeBranchNameForUrl(claudeBranch)}`;
               branchLink = `\n[View branch](${branchUrl})`;
             } else {
               console.log(
@@ -117,7 +118,7 @@ export async function checkAndCommitOrDeleteBranch(
           } catch (gitError) {
             console.error("Error checking/committing changes:", gitError);
             // If we can't check git status, assume the branch might have changes
-            const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${claudeBranch}`;
+            const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${encodeBranchNameForUrl(claudeBranch)}`;
             branchLink = `\n[View branch](${branchUrl})`;
           }
         } else {
@@ -128,13 +129,13 @@ export async function checkAndCommitOrDeleteBranch(
         }
       } else {
         // Only add branch link if there are commits
-        const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${claudeBranch}`;
+        const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${encodeBranchNameForUrl(claudeBranch)}`;
         branchLink = `\n[View branch](${branchUrl})`;
       }
     } catch (error) {
       console.error("Error comparing commits on Claude branch:", error);
       // If we can't compare but the branch exists remotely, include the branch link
-      const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${claudeBranch}`;
+      const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${encodeBranchNameForUrl(claudeBranch)}`;
       branchLink = `\n[View branch](${branchUrl})`;
     }
   }

src/github/operations/comment-logic.ts

@@ -1,5 +1,6 @@
 import { GITHUB_SERVER_URL } from "../api/config";
 import { redactSecrets } from "../utils/sanitizer";
+import { encodeBranchNameForUrl } from "./comments/common";
 
 export type ExecutionDetails = {
   total_cost_usd?: number;
@@ -161,7 +162,7 @@ export function updateCommentBody(input: CommentUpdateInput): string {
       // Extract owner/repo from jobUrl
       const repoMatch = jobUrl.match(/github\.com\/([^\/]+)\/([^\/]+)\//);
       if (repoMatch) {
-        branchUrl = `${GITHUB_SERVER_URL}/${repoMatch[1]}/${repoMatch[2]}/tree/${finalBranchName}`;
+        branchUrl = `${GITHUB_SERVER_URL}/${repoMatch[1]}/${repoMatch[2]}/tree/${encodeBranchNameForUrl(finalBranchName)}`;
       }
     }
 

src/github/operations/comments/common.ts

@@ -12,12 +12,17 @@ export function createJobRunLink(
   return `[View job run](${jobRunUrl})`;
 }
 
+/** Encode Git-ref path segments without turning `/` into `%2F`. */
+export function encodeBranchNameForUrl(branchName: string): string {
+  return branchName.split("/").map(encodeURIComponent).join("/");
+}
+
 export function createBranchLink(
   owner: string,
   repo: string,
   branchName: string,
 ): string {
-  const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${branchName}`;
+  const branchUrl = `${GITHUB_SERVER_URL}/${owner}/${repo}/tree/${encodeBranchNameForUrl(branchName)}`;
   return `\n[View branch](${branchUrl})`;
 }
 

test/comments-common.test.ts

@@ -36,6 +36,12 @@ describe("comments/common", () => {
       );
     });
 
+    test("encodes URL-significant characters in a branch name", () => {
+      expect(createBranchLink("o", "r", "claude/fix#123")).toBe(
+        `\n[View branch](${GITHUB_SERVER_URL}/o/r/tree/claude/fix%23123)`,
+      );
+    });
+
     test("prefixes the link with a newline so it renders on its own line", () => {
       expect(createBranchLink("o", "r", "main").startsWith("\n")).toBe(true);
     });