fix(code-mappings): handle malformed source path (#105683)

Fixes SENTRY-47GS

Passing a malformed/empty `source_path` when creating a code mapping
causes `source_path` to be `""`, which results in an error here (since
`stack_path` always will end with `""`)
```
    elif stack_path.endswith(source_path):
        stack_prefix = stack_path.rpartition(source_path)[0]
```
Since the user can input invalid `source_path`s, we should handle this
and return 400 instead of 500

Author: cvxluo

src/sentry/api/endpoints/project_repo_path_parsing.py

@@ -15,7 +15,10 @@
 from sentry.integrations.services.integration import RpcIntegration, integration_service
 from sentry.integrations.source_code_management.repository import RepositoryIntegration
 from sentry.issues.auto_source_code_config.code_mapping import find_roots
-from sentry.issues.auto_source_code_config.errors import UnsupportedFrameInfo
+from sentry.issues.auto_source_code_config.errors import (
+    UnexpectedPathException,
+    UnsupportedFrameInfo,
+)
 from sentry.issues.auto_source_code_config.frame_info import FrameInfo, create_frame_info
 from sentry.models.project import Project
 from sentry.models.repository import Repository
@@ -142,7 +145,14 @@ def post(self, request: Request, project: Project) -> Response:
 
         branch = installation.extract_branch_from_source_url(repo, source_url)
         source_path = installation.extract_source_path_from_source_url(repo, source_url)
-        stack_root, source_root = find_roots(frame_info, source_path)
+
+        try:
+            stack_root, source_root = find_roots(frame_info, source_path)
+        except UnexpectedPathException:
+            return self.respond(
+                {"detail": "Could not determine code mapping from provided paths"},
+                status=status.HTTP_400_BAD_REQUEST,
+            )
 
         return self.respond(
             {

src/sentry/issues/auto_source_code_config/code_mapping.py

@@ -420,6 +420,9 @@ def find_roots(frame_filename: FrameInfo, source_path: str) -> tuple[str, str]:
     Returns a tuple containing the stack_root, and the source_root.
     If there is no overlap, raise an exception since this should not happen
     """
+    if not source_path:
+        raise UnexpectedPathException("Source path is empty")
+
     stack_path = frame_filename.raw_path
     stack_root = ""
     if stack_path[0] == "/" or stack_path[0] == "\\":

tests/sentry/api/endpoints/test_project_repo_path_parsing.py

@@ -180,6 +180,13 @@ def test_bad_source_url(self) -> None:
         assert resp.status_code == 400, resp.content
         assert resp.data == {"sourceUrl": ["Enter a valid URL."]}
 
+    def test_malformed_source_url_empty_source_path(self) -> None:
+        source_url = "https://github.com/getsentry/sentry/tree/master/src/sentry/api/endpoints/project_stacktrace_link.py"
+        stack_path = "sentry/api/endpoints/project_stacktrace_link.py"
+        resp = self.make_post(source_url, stack_path)
+        assert resp.status_code == 400, resp.content
+        assert resp.data == {"detail": "Could not determine code mapping from provided paths"}
+
     def test_wrong_file(self) -> None:
         source_url = "https://github.com/getsentry/sentry/blob/master/src/sentry/api/endpoints/project_releases.py"
         stack_path = "sentry/api/endpoints/project_stacktrace_link.py"

tests/sentry/issues/auto_source_code_config/test_code_mapping.py

@@ -308,6 +308,13 @@ def test_find_roots_bad_source_path(self) -> None:
                 "nothing/something.js",
             )
 
+    def test_find_roots_empty_source_path(self) -> None:
+        with pytest.raises(UnexpectedPathException):
+            find_roots(
+                create_frame_info({"filename": "sentry/foo.py"}),
+                "",
+            )
+
     def test_find_roots_windows_path_with_spaces(self) -> None:
         stacktrace_root, source_path = find_roots(
             create_frame_info({"filename": "C:\\Program Files\\MyApp\\src\\file.py"}), "src/file.py"