aver: regex-match effects opener under arbitrary whitespace (CR review)

jasisz · jasisz · commit 661a0b702fe8 · 2026-04-29T11:08:12.000+02:00
The opener check used startswith("effects [", "effects["), which misses
LLM output with non-canonical whitespace (multiple spaces, tab) between
the keyword and the bracket — variants the Aver parser still accepts.
Replace the prefix tuple with _AVER_EFFECTS_OPEN_RE = re.compile(
r"^effects\\s*\\[") and cover the variants in TestStripModuleEffects.
diff --git a/tests/test_runner.py b/tests/test_runner.py
@@ -947,6 +947,27 @@ def test_no_op_when_no_module_declaration(self):
         result = _strip_module_effects(code)
         assert result == code
 
+    def test_strips_arbitrary_whitespace_between_keyword_and_bracket(self):
+        # LLM-formatted output may emit any whitespace between
+        # `effects` and `[`; the strip must catch every variant the
+        # Aver parser accepts, not just the canonical single space.
+        for opener in ("effects[", "effects [", "effects  [", "effects\t["):
+            code = (
+                "module M\n"
+                '    intent = "t"\n'
+                f"    {opener}Console.print]\n"
+                "\n"
+                "fn f() -> Unit\n"
+                "    ! [Console.print]\n"
+                '    Console.print("hi")\n'
+            )
+            result = _strip_module_effects(code)
+            header_part = result.split("fn f")[0]
+            assert "Console.print]" not in header_part, (
+                f"failed to strip header with opener: {opener!r}"
+            )
+            assert "fn f" in result
+
     def test_only_strips_inside_module_header(self):
         # An `effects [...]`-shaped line that appears below a
         # function body must not be removed; only the module-header
diff --git a/vera_bench/runner.py b/vera_bench/runner.py
@@ -566,6 +566,9 @@ def _strip_aver_main(code: str) -> str:
     return "\n".join(result_lines)
 
 
+_AVER_EFFECTS_OPEN_RE = re.compile(r"^effects\s*\[")
+
+
 def _strip_module_effects(code: str) -> str:
     """Remove the module header's `effects [...]` declaration if present.
 
@@ -617,7 +620,7 @@ def _strip_module_effects(code: str) -> str:
         if (
             in_module_header
             and indent_len > 0
-            and (stripped.startswith("effects [") or stripped.startswith("effects["))
+            and _AVER_EFFECTS_OPEN_RE.match(stripped)
         ):
             if stripped.endswith("]"):
                 continue
