fix(server): Commit, push & PR no longer pushes the default branch into itself

apps/server/src/git/GitManager.test.ts

@@ -3503,6 +3503,125 @@ it.layer(layerGitManagerTest)("GitManager", (it) => {
     }),
   );
 
+  it.effect.each([
+    { localBranch: "develop" },
+    // Pushes to origin's develop under a name that differs from the base.
+    { localBranch: "origin/develop" },
+  ] as const)(
+    "commit_push_pr refuses to commit or push on the default branch when origin/HEAD is missing ($localBranch)",
+    ({ localBranch }) =>
+      Effect.gen(function* () {
+        const repoDir = yield* makeTempDir("t3code-git-manager-");
+        yield* initRepo(repoDir);
+        yield* runGit(repoDir, ["branch", "-m", "main", "develop"]);
+        const remoteDir = yield* createBareRemote();
+        yield* runGit(repoDir, ["remote", "add", "origin", remoteDir]);
+        yield* runGit(repoDir, ["push", "-u", "origin", "develop"]);
+        if (localBranch !== "develop") yield* runGit(repoDir, ["checkout", "-b", localBranch]);
+        const readRemoteDevelop = runGit(repoDir, [
+          "ls-remote",
+          "origin",
+          "refs/heads/develop",
+        ]).pipe(Effect.map((output) => output.stdout));
+        const remoteBefore = yield* readRemoteDevelop;
+        const localBefore = (yield* runGit(repoDir, ["rev-parse", "HEAD"])).stdout;
+        NodeFS.writeFileSync(NodePath.join(repoDir, "change.txt"), "change\n");
+
+        const { manager } = yield* makeManager({
+          providerScenario: { defaultBranch: "develop", prListSequence: [[], []] },
+        });
+
+        const error = yield* runStackedAction(manager, {
+          cwd: repoDir,
+          action: "commit_push_pr",
+        }).pipe(Effect.flip);
+
+        expect(yield* readRemoteDevelop).toBe(remoteBefore);
+        expect((yield* runGit(repoDir, ["rev-parse", "HEAD"])).stdout).toBe(localBefore);
+        expect(error.message).toContain("develop is the base branch");
+      }),
+  );
+
+  it.effect("commit_push_pr on the default branch returns its open PR into another base", () =>
+    Effect.gen(function* () {
+      const repoDir = yield* makeTempDir("t3code-git-manager-");
+      yield* initRepo(repoDir);
+      const remoteDir = yield* createBareRemote();
+      yield* runGit(repoDir, ["remote", "add", "origin", remoteDir]);
+      yield* runGit(repoDir, ["push", "-u", "origin", "main"]);
+      const releasePr = {
+        number: 43,
+        title: "Release",
+        url: "https://github.com/pingdotgg/codething-mvp/pull/43",
+        baseRefName: "release",
+        headRefName: "main",
+      };
+
+      const { manager } = yield* makeManager({
+        providerScenario: { defaultBranch: "main", prListSequence: [[releasePr], [releasePr]] },
+      });
+      const result = yield* runStackedAction(manager, {
+        cwd: repoDir,
+        action: "commit_push_pr",
+      });
+
+      expect(result.pr.status).toBe("opened_existing");
+      expect(result.pr.number).toBe(43);
+    }),
+  );
+
+  it.effect(
+    "commit_push_pr publishes a branch that tracks the default branch under its own name",
+    () =>
+      Effect.gen(function* () {
+        const repoDir = yield* makeTempDir("t3code-git-manager-");
+        yield* initRepo(repoDir);
+        yield* runGit(repoDir, ["branch", "-m", "main", "develop"]);
+        const remoteDir = yield* createBareRemote();
+        yield* runGit(repoDir, ["remote", "add", "origin", remoteDir]);
+        yield* runGit(repoDir, ["push", "-u", "origin", "develop"]);
+        yield* runGit(repoDir, ["checkout", "-b", "t3code/feature", "--track", "origin/develop"]);
+        const readRemoteDevelop = runGit(repoDir, [
+          "ls-remote",
+          "origin",
+          "refs/heads/develop",
+        ]).pipe(Effect.map((output) => output.stdout));
+        const remoteBefore = yield* readRemoteDevelop;
+        NodeFS.writeFileSync(NodePath.join(repoDir, "change.txt"), "change\n");
+
+        const { manager, providerCalls } = yield* makeManager({
+          providerScenario: {
+            defaultBranch: "develop",
+            prListSequence: [
+              [],
+              [
+                {
+                  number: 506,
+                  title: "Feature",
+                  url: "https://github.com/pingdotgg/codething-mvp/pull/506",
+                  baseRefName: "develop",
+                  headRefName: "t3code/feature",
+                },
+              ],
+            ],
+          },
+        });
+
+        const result = yield* runStackedAction(manager, {
+          cwd: repoDir,
+          action: "commit_push_pr",
+        });
+
+        expect(result.pr.status).toBe("created");
+        expect(yield* readRemoteDevelop).toBe(remoteBefore);
+        expect(
+          created(providerCalls).some(
+            (call) => call.baseRefName === "develop" && call.headSelector === "t3code/feature",
+          ),
+        ).toBe(true);
+      }),
+  );
+
   it.effect("create_pr reports a created PR when the lookup after creation fails", () =>
     Effect.gen(function* () {
       const repoDir = yield* makeTempDir("t3code-git-manager-");
@@ -4355,6 +4474,74 @@ it.layer(layerGitManagerTest)("GitManager", (it) => {
     }),
   );
 
+  it.effect("commit_push_pr publishes the default branch to the push remote's fork", () =>
+    Effect.gen(function* () {
+      const repoDir = yield* makeTempDir("t3code-git-manager-");
+      yield* initRepo(repoDir);
+      const originDir = yield* createBareRemote();
+      const forkDir = yield* createBareRemote();
+      yield* runGit(repoDir, ["remote", "add", "origin", originDir]);
+      yield* runGit(repoDir, ["push", "origin", "main"]);
+      yield* runGit(repoDir, ["remote", "add", "fork", forkDir]);
+      yield* runGit(repoDir, ["push", "fork", "main"]);
+      yield* runGit(repoDir, ["config", "remote.pushDefault", "fork"]);
+      yield* configureVisibleRemoteUrlWithLocalRewrite(
+        repoDir,
+        "origin",
+        "git@github.com:pingdotgg/codething-mvp.git",
+        originDir,
+      );
+      yield* configureVisibleRemoteUrlWithLocalRewrite(
+        repoDir,
+        "fork",
+        "git@github.com:octocat/codething-mvp.git",
+        forkDir,
+      );
+      const readOriginMain = runGit(repoDir, ["ls-remote", "origin", "refs/heads/main"]).pipe(
+        Effect.map((output) => output.stdout),
+      );
+      const originBefore = yield* readOriginMain;
+      NodeFS.writeFileSync(NodePath.join(repoDir, "change.txt"), "change\n");
+
+      const { manager, providerCalls } = yield* makeManager({
+        providerScenario: {
+          defaultBranch: "main",
+          prListSequenceByHeadSelector: {
+            "octocat:main": [
+              [],
+              [
+                {
+                  number: 189,
+                  title: "Contribute from main",
+                  url: "https://github.com/pingdotgg/codething-mvp/pull/189",
+                  baseRefName: "main",
+                  headRefName: "main",
+                  state: "open",
+                  isCrossRepository: true,
+                  headRepositoryNameWithOwner: "octocat/codething-mvp",
+                  headRepositoryOwnerLogin: "octocat",
+                },
+              ],
+            ],
+          },
+        },
+      });
+
+      const result = yield* runStackedAction(manager, {
+        cwd: repoDir,
+        action: "commit_push_pr",
+      });
+
+      expect(result.pr.status).toBe("created");
+      expect(yield* readOriginMain).toBe(originBefore);
+      expect(
+        created(providerCalls).some(
+          (call) => call.baseRefName === "main" && call.headSelector === "octocat:main",
+        ),
+      ).toBe(true);
+    }),
+  );
+
   it.effect("rejects push/pr actions from detached HEAD", () =>
     Effect.gen(function* () {
       const repoDir = yield* makeTempDir("t3code-git-manager-");

apps/server/src/git/GitManager.ts

@@ -2282,6 +2282,34 @@ export const make = Effect.gen(function* () {
     };
   });
 
+  const ensurePrHeadIsNotBase = Effect.fn("ensurePrHeadIsNotBase")(function* (
+    cwd: string,
+    status: { branch: string; upstreamRef: string | null; hasUpstream: boolean },
+    changeRequestLabel: string,
+  ) {
+    const target = yield* gitCore.resolvePushTarget(cwd, status);
+    if (!target) return;
+    const headContext = yield* resolveBranchHeadContext(cwd, {
+      branch: status.branch,
+      upstreamRef: `${target.remoteName}/${target.branchName}`,
+      remoteName: target.remoteName,
+    });
+    if (headContext.isCrossRepository) return;
+    const { baseBranch } = yield* resolvePrBase(
+      cwd,
+      status.branch,
+      status.upstreamRef,
+      headContext,
+    );
+    if (baseBranch !== target.branchName) return;
+    if (yield* findOpenPr(cwd, headContext)) return;
+    return yield* new GitManagerError({
+      operation: "runStackedAction",
+      cwd,
+      detail: `${baseBranch} is the base branch. Check out a feature branch to create ${changeRequestLabel}.`,
+    });
+  });
+
   const runPrStep = Effect.fn("runPrStep")(function* (
     settings: SourceControlTextGenerationSettings,
     cwd: string,
@@ -3251,6 +3279,15 @@ export const make = Effect.gen(function* () {
         const currentBranch = branchStep.name ?? initialStatus.branch;
         const commitAction = isCommitAction(input.action) ? input.action : null;
         const changeRequestTerms = wantsPr ? yield* changeRequestTermsFor(input.cwd) : null;
+        // A stale or missing origin/HEAD hides the default branch from status, so check here
+        // before anything is committed or pushed to it.
+        if (changeRequestTerms && !input.featureBranch && initialStatus.branch) {
+          yield* ensurePrHeadIsNotBase(
+            input.cwd,
+            { ...initialStatus, branch: initialStatus.branch },
+            changeRequestTerms.shortLabelWithArticle,
+          );
+        }
 
         const commit = commitAction
           ? yield* Ref.set(currentPhase, Option.some("commit")).pipe(

apps/server/src/vcs/GitVcsDriver.ts

@@ -181,6 +181,11 @@ export interface GitPushResult {
   setUpstream?: boolean | undefined;
 }
 
+export interface GitPushTarget {
+  remoteName: string;
+  branchName: string;
+}
+
 export interface GitRangeContext {
   commitSummary: string;
   diffSummary: string;
@@ -339,6 +344,11 @@ export class GitVcsDriver extends Context.Service<
       fallbackBranch: string | null,
       options?: { readonly remoteName?: string | null },
     ) => Effect.Effect<GitPushResult, GitCommandError>;
+    /** Where `pushCurrentBranch` would push the checked-out branch; null with no remote or when Git picks. */
+    readonly resolvePushTarget: (
+      cwd: string,
+      current: { readonly branch: string; readonly hasUpstream: boolean },
+    ) => Effect.Effect<GitPushTarget | null, GitCommandError>;
     readonly readRangeContext: (
       cwd: string,
       baseRef: string,