feat: enforce branches-only author mutation worktree guard (Closes #274)

Add author_mutation_worktree assessment and integrate it into MCP preflight so author mutations fail closed outside branches/ session worktrees, with tests for control-checkout and branches-path cases. Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
2026-07-07 05:44:58 -04:00
parent f87101ccaa
commit 6779d903f2
3 changed files with 247 additions and 24 deletions
@@ -0,0 +1,96 @@
+"""Tests for branches-only author mutation worktree guard (#274)."""
+
+from __future__ import annotations
+
+import sys
+import unittest
+from pathlib import Path
+from unittest import mock
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import author_mutation_worktree as amw  # noqa: E402
+
+
+class TestPathUnderBranches(unittest.TestCase):
+    ROOT = "/repo/Gitea-Tools"
+
+    def test_branches_subdirectory_passes(self):
+        self.assertTrue(
+            amw.is_path_under_branches(f"{self.ROOT}/branches/issue-274", self.ROOT)
+        )
+
+    def test_control_checkout_fails(self):
+        self.assertFalse(amw.is_path_under_branches(self.ROOT, self.ROOT))
+
+    def test_sibling_directory_fails(self):
+        self.assertFalse(
+            amw.is_path_under_branches("/repo/other-checkout", self.ROOT)
+        )
+
+
+class TestAssessAuthorMutationWorktree(unittest.TestCase):
+    ROOT = "/repo/Gitea-Tools"
+
+    def test_branches_worktree_passes(self):
+        result = amw.assess_author_mutation_worktree(
+            workspace_path=f"{self.ROOT}/branches/issue-274",
+            project_root=self.ROOT,
+            current_branch="feat/issue-274-branches-only-worktrees",
+        )
+        self.assertTrue(result["proven"])
+        self.assertFalse(result["block"])
+
+    def test_control_checkout_blocks(self):
+        result = amw.assess_author_mutation_worktree(
+            workspace_path=self.ROOT,
+            project_root=self.ROOT,
+            current_branch="master",
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(result["block"])
+        self.assertIn("control checkout", result["reasons"][0])
+
+    def test_drifted_control_branch_blocks(self):
+        result = amw.assess_author_mutation_worktree(
+            workspace_path=self.ROOT,
+            project_root=self.ROOT,
+            current_branch="feat/some-task",
+        )
+        self.assertTrue(result["block"])
+        self.assertTrue(any("drift" in r for r in result["reasons"]))
+
+
+class TestPreflightIntegration(unittest.TestCase):
+    def test_verify_preflight_blocks_control_checkout_with_test_porcelain(self):
+        import mcp_server
+
+        mcp_server._preflight_whoami_called = True
+        mcp_server._preflight_capability_called = True
+        mcp_server._preflight_resolved_role = "author"
+        with mock.patch.dict(
+            "os.environ",
+            {"GITEA_TEST_PORCELAIN": ""},
+            clear=False,
+        ):
+            with self.assertRaises(RuntimeError) as ctx:
+                mcp_server.verify_preflight_purity()
+        self.assertIn("Branches-only mutation guard", str(ctx.exception))
+
+    def test_verify_preflight_allows_branches_worktree(self):
+        import mcp_server
+
+        mcp_server._preflight_whoami_called = True
+        mcp_server._preflight_capability_called = True
+        mcp_server._preflight_resolved_role = "author"
+        worktree = "/repo/Gitea-Tools/branches/issue-274"
+        with mock.patch.dict(
+            "os.environ",
+            {"GITEA_TEST_PORCELAIN": ""},
+            clear=False,
+        ):
+            mcp_server.verify_preflight_purity(worktree_path=worktree)
+
+
+if __name__ == "__main__":
+    unittest.main()