Don't error on symlinks and executables when they don't have to be touched anyway

src/git.ts

@@ -74,6 +74,12 @@ export const commitChangesFromRepo = async ({
       ) {
         return null;
       }
+      const prevOid = await commit?.oid();
+      const currentOid = await workdir?.oid();
+      // Don't include files that haven't changed, and exist in both trees
+      if (prevOid === currentOid && !commit === !workdir) {
+        return null;
+      }
       if (
         (await commit?.mode()) === FILE_MODES.symlink ||
         (await workdir?.mode()) === FILE_MODES.symlink
@@ -87,12 +93,6 @@ export const commitChangesFromRepo = async ({
           `Unexpected executable file at ${filepath}, GitHub API only supports non-executable files and directories. You may need to add this file to .gitignore`,
         );
       }
-      const prevOid = await commit?.oid();
-      const currentOid = await workdir?.oid();
-      // Don't include files that haven't changed, and exist in both trees
-      if (prevOid === currentOid && !commit === !workdir) {
-        return null;
-      }
       // Iterate through anything that may be a directory in either the
       // current commit or the working directory
       if (

src/test/integration/git.test.ts

@@ -85,7 +85,9 @@ const makeFileChanges = async (
     | "with-executable-file"
     | "with-ignored-symlink"
     | "with-included-valid-symlink"
-    | "with-included-invalid-symlink",
+    | "with-included-invalid-symlink"
+    | "with-unchanged-symlink"
+    | "with-changed-symlink",
 ) => {
   // Update an existing file
   await fs.promises.writeFile(
@@ -164,6 +166,40 @@ const makeFileChanges = async (
       path.join(repoDirectory, "some-dir", "nested"),
     );
   }
+  if (
+    changegroup === "with-unchanged-symlink" ||
+    changegroup === "with-changed-symlink"
+  ) {
+    // Create a symlink and commit it locally first
+    await fs.promises.mkdir(path.join(repoDirectory, "some-dir"), {
+      recursive: true,
+    });
+    await fs.promises.symlink(
+      path.join(repoDirectory, "README.md"),
+      path.join(repoDirectory, "some-dir", "nested"),
+    );
+    // Commit the symlink locally so it's in the base commit tree
+    await git.add({
+      fs,
+      dir: repoDirectory,
+      filepath: "some-dir/nested",
+    });
+    await git.commit({
+      fs,
+      dir: repoDirectory,
+      message: "Add symlink",
+      author: { name: "Test", email: "[email protected]" },
+    });
+
+    if (changegroup === "with-changed-symlink") {
+      // Change the symlink to point to a different target
+      await fs.promises.rm(path.join(repoDirectory, "some-dir", "nested"));
+      await fs.promises.symlink(
+        path.join(repoDirectory, "LICENSE"),
+        path.join(repoDirectory, "some-dir", "nested"),
+      );
+    }
+  }
 };
 
 const makeFileChangeAssertions = async (branch: string) => {
@@ -324,6 +360,62 @@ describe("git", () => {
       });
     }
 
+    it(`should allow unchanged symlinks without throwing symlink error`, async () => {
+      const branch = `${TEST_BRANCH_PREFIX}-multiple-changes-with-unchanged-symlink`;
+      branches.push(branch);
+
+      await fs.promises.mkdir(testDir, { recursive: true });
+      const repoDirectory = path.join(testDir, `repo-1-with-unchanged-symlink`);
+
+      // Clone the git repo locally using the git cli and child-process
+      await new Promise<void>((resolve, reject) => {
+        const p = execFile(
+          "git",
+          ["clone", process.cwd(), `repo-1-with-unchanged-symlink`],
+          { cwd: testDir },
+          (error) => {
+            if (error) {
+              reject(error);
+            } else {
+              resolve();
+            }
+          },
+        );
+        p.stdout?.pipe(process.stdout);
+        p.stderr?.pipe(process.stderr);
+      });
+
+      await makeFileChanges(repoDirectory, "with-unchanged-symlink");
+
+      // The symlink was committed locally and is unchanged in workdir.
+      // When using local HEAD as base, the symlink should be detected as
+      // unchanged and skipped (no symlink error thrown during tree walk).
+      // The actual GitHub push may fail because the local commit doesn't
+      // exist on GitHub, but that's OK - we're testing the tree walk logic.
+      try {
+        await commitChangesFromRepo({
+          octokit,
+          ...REPO,
+          branch,
+          message: {
+            headline: "Test commit",
+            body: "This is a test commit",
+          },
+          cwd: repoDirectory,
+          log,
+        });
+
+        // If push somehow succeeded, verify the file changes
+        await waitForGitHubToBeReady();
+        await makeFileChangeAssertions(branch);
+      } catch (error) {
+        // The error should NOT be about symlinks - that would mean tree walk
+        // failed to skip the unchanged symlink
+        expect((error as Error).message).not.toContain("Unexpected symlink");
+        expect((error as Error).message).not.toContain("Unexpected executable");
+      }
+    });
+
     describe(`should throw appropriate error when symlink is present`, () => {
       it(`and file does not exist`, async () => {
         const branch = `${TEST_BRANCH_PREFIX}-invalid-symlink-error`;
@@ -414,6 +506,51 @@ describe("git", () => {
           "Unexpected symlink at some-dir/nested, GitHub API only supports files and directories. You may need to add this file to .gitignore",
         );
       });
+
+      it(`and symlink was changed`, async () => {
+        const branch = `${TEST_BRANCH_PREFIX}-changed-symlink-error`;
+        branches.push(branch);
+
+        await fs.promises.mkdir(testDir, { recursive: true });
+        const repoDirectory = path.join(testDir, `repo-changed-symlink`);
+
+        // Clone the git repo locally using the git cli and child-process
+        await new Promise<void>((resolve, reject) => {
+          const p = execFile(
+            "git",
+            ["clone", process.cwd(), `repo-changed-symlink`],
+            { cwd: testDir },
+            (error) => {
+              if (error) {
+                reject(error);
+              } else {
+                resolve();
+              }
+            },
+          );
+          p.stdout?.pipe(process.stdout);
+          p.stderr?.pipe(process.stderr);
+        });
+
+        await makeFileChanges(repoDirectory, "with-changed-symlink");
+
+        // Push the changes
+        await expect(() =>
+          commitChangesFromRepo({
+            octokit,
+            ...REPO,
+            branch,
+            message: {
+              headline: "Test commit",
+              body: "This is a test commit",
+            },
+            cwd: repoDirectory,
+            log,
+          }),
+        ).rejects.toThrow(
+          "Unexpected symlink at some-dir/nested, GitHub API only supports files and directories. You may need to add this file to .gitignore",
+        );
+      });
     });
 
     it(`should throw appropriate error when executable file is present`, async () => {