[bitbucket-server] fix parsing of branch name

Context URLs of BitBucket Server may include a search param "at" to specify a branch fully qualified. GItpod's context parser results are expected to provide a simple "ref" name for branches.

Author: AlexTugarev

Diff for: components/server/src/bitbucket-server/bitbucket-server-context-parser.spec.ts

@@ -19,6 +19,7 @@ import { Config } from "../config";
 import { TokenProvider } from "../user/token-provider";
 import { BitbucketServerApi } from "./bitbucket-server-api";
 import { HostContextProvider } from "../auth/host-context-provider";
+import { URL } from "url";
 
 @suite(timeout(10000), skipIfEnvVarNotSet("GITPOD_TEST_TOKEN_BITBUCKET_SERVER"))
 class TestBitbucketServerContextParser {
@@ -304,6 +305,14 @@ class TestBitbucketServerContextParser {
             },
         });
     }
+
+    @test.only test_toSimpleBranchName() {
+        const url = new URL(
+            "https://bitbucket.gitpod-self-hosted.com/projects/FOO/repos/repo123/browse?at=refs%2Fheads%2Ffoo",
+        );
+        const branchName = this.parser.toSimpleBranchName(url.searchParams.get("at")!);
+        expect(branchName).to.equal("foo");
+    }
 }
 
 module.exports = new TestBitbucketServerContextParser();

Diff for: components/server/src/bitbucket-server/bitbucket-server-context-parser.ts

@@ -32,7 +32,8 @@ export class BitbucketServerContextParser extends AbstractContextParser implemen
             );
 
             if (searchParams.has("at")) {
-                more.ref = decodeURIComponent(searchParams.get("at")!);
+                const branchName = this.toSimpleBranchName(decodeURIComponent(searchParams.get("at")!));
+                more.ref = branchName;
                 more.refType = "branch";
             }
 
@@ -58,6 +59,12 @@ export class BitbucketServerContextParser extends AbstractContextParser implemen
         }
     }
 
+    // Example: For a given context URL https://HOST/projects/FOO/repos/repo123/browse?at=refs%2Fheads%2Ffoo
+    // we need to parse the simple branch name `foo`.
+    public toSimpleBranchName(qualifiedBranchName: string | undefined) {
+        return qualifiedBranchName?.replace("refs/heads/", "");
+    }
+
     public async parseURL(user: User, contextUrl: string): Promise<{ repoKind: "projects" | "users" } & URLParts> {
         const url = new URL(contextUrl);
         const pathname = url.pathname.replace(/^\//, "").replace(/\/$/, ""); // pathname without leading and trailing slash