fix: require boundary-check handlers to raise on every path

Author: kvlonge

scripts/python_boundary/_helpers/native_errors.py

@@ -40,7 +40,7 @@ def _native_names(tree: ast.Module) -> frozenset[str]:
             names.update(
                 alias.asname or alias.name
                 for alias in node.names
-                if native_module or NATIVE_MARKER in alias.name
+                if native_module or _names_native(alias.name)
             )
         elif isinstance(node, ast.Import):
             names.update(
@@ -53,7 +53,11 @@ def _native_names(tree: ast.Module) -> frozenset[str]:
 
 def _is_native_module(module: str) -> bool:
     parts: list[str] = module.split(".")
-    return parts[0] == NATIVE_PACKAGE and any(NATIVE_MARKER in part for part in parts[1:])
+    return parts[0] == NATIVE_PACKAGE and any(_names_native(part) for part in parts[1:])
+
+
+def _names_native(name: str) -> bool:
+    return NATIVE_MARKER in name.split("_")
 
 
 def _guarded_blocks(tree: ast.Module) -> list[tuple[str, ast.stmt]]:
@@ -89,7 +93,17 @@ def _swallowing_lines(*, node: ast.stmt, native: frozenset[str]) -> list[int]:
 
 
 def _always_raises(handler: ast.ExceptHandler) -> bool:
-    return any(isinstance(statement, ast.Raise) for statement in handler.body)
+    return isinstance(handler.body[-1], ast.Raise) and not any(
+        _exits_early(statement) for statement in handler.body
+    )
+
+
+def _exits_early(node: ast.AST) -> bool:
+    if isinstance(node, ast.Return | ast.Break | ast.Continue):
+        return True
+    if isinstance(node, ast.FunctionDef | ast.AsyncFunctionDef | ast.Lambda | ast.ClassDef):
+        return False
+    return any(_exits_early(child) for child in ast.iter_child_nodes(node))
 
 
 def _is_suppress(expression: ast.expr) -> bool:

tests/unit/scripts/python_boundary/main/test_check.py

@@ -34,9 +34,9 @@
     "    try:\n"
     "        return content_digest([text])\n"
     "    except ValueError:\n"
-    "        if strict:\n"
-    "            raise\n"
-    "        return None\n"
+    "        if not strict:\n"
+    "            return None\n"
+    "        raise\n"
 )
 SUPPRESSED: str = (
     "import contextlib\n"
@@ -65,6 +65,23 @@
             policy="remaining_lines = 2\n" + STAYS,
             expected_messages=("2 movable Python lines remain",),
         ),
+        PythonBoundaryTestCase(
+            description="names that only contain the letters native are not native calls",
+            source_files={
+                "compiler/plan.py": (
+                    "from sqlbuild.compiler.alternatives import alternative_plan\n"
+                    "\n"
+                    "\n"
+                    "def plan():\n"
+                    "    try:\n"
+                    "        return alternative_plan()\n"
+                    "    except ValueError:\n"
+                    "        return None\n"
+                )
+            },
+            policy="remaining_lines = 8\n",
+            expected_messages=("8 movable Python lines remain",),
+        ),
         PythonBoundaryTestCase(
             description="re-raised native failures are allowed",
             source_files={"compiler/keys.py": RERAISED},