--feature-flag: strict bool coercion + drop invalid values

Per @rattus128 review on PR #13685: silently coercing typo'd bool values
(e.g. `--feature-flag show_signin_button=ture`) to `False` was a confusing
UX. Make bool coercion strict and drop unparseable flags entirely.

- `_coerce_bool`: accept only `true`/`false` (case-insensitive); raise
  `ValueError` for anything else (`ture`, `yes`, `1`, ``).
- `_coerce_flag_value`: no longer swallows exceptions; raises on bad
  coercion so the caller decides what to do.
- `_parse_cli_feature_flags`: catches `ValueError`/`TypeError`, logs a
  warning ("dropping flag"), and omits the flag from the result. ComfyUI
  still starts; `SERVER_FEATURE_FLAGS` retains the registered default;
  other valid `--feature-flag` entries on the same command line are
  unaffected.

Tests:
- `test_bool_typo_raises`: `ture`/`yes`/`1`/`""` all raise ValueError.
- `test_failed_int_coercion_raises`: replaces the old "falls back to
  string" test now that coercion failures propagate.
- `test_invalid_bool_value_dropped`: parser drops the bad flag and logs
  a warning, while a valid sibling flag still parses.

19/19 unit tests pass.

Co-authored-by: Amp <amp@ampcode.com>
Amp-Thread-ID: https://ampcode.com/threads/T-019df5a8-36be-7107-a4af-c7e4f51687df

comfy_api/feature_flags.py

@@ -28,8 +28,22 @@ CLI_FEATURE_FLAG_REGISTRY: dict[str, FeatureFlagInfo] = {
 }
 
 
+def _coerce_bool(v: str) -> bool:
+    """Strict bool coercion: only 'true'/'false' (case-insensitive).
+
+    Anything else raises ValueError so the caller can warn and drop the flag,
+    rather than silently treating typos like 'ture' or 'yes' as False.
+    """
+    lower = v.lower()
+    if lower == "true":
+        return True
+    if lower == "false":
+        return False
+    raise ValueError(f"expected 'true' or 'false', got {v!r}")
+
+
 _COERCE_FNS: dict[str, Any] = {
-    "bool": lambda v: v.lower() == "true",
+    "bool": _coerce_bool,
     "int": lambda v: int(v),
     "float": lambda v: float(v),
 }
@@ -38,8 +52,9 @@ _COERCE_FNS: dict[str, Any] = {
 def _coerce_flag_value(key: str, raw_value: str) -> Any:
     """Coerce a raw string value using the registry type, or keep as string.
 
-    Returns the raw string if the key is unregistered, the type is unknown,
+    Returns the raw string if the key is unregistered or the type is unknown.
-    or coercion fails (with a warning logged in the failure case).
+    Raises ValueError/TypeError if the key is registered with a known type but
+    the value cannot be coerced; callers are expected to warn and drop the flag.
     """
     info = CLI_FEATURE_FLAG_REGISTRY.get(key)
     if info is None:
@@ -47,20 +62,16 @@ def _coerce_flag_value(key: str, raw_value: str) -> Any:
     coerce = _COERCE_FNS.get(info["type"])
     if coerce is None:
         return raw_value
-    try:
+    return coerce(raw_value)
-        return coerce(raw_value)
-    except (ValueError, TypeError):
-        logging.warning(
-            "Could not coerce --feature-flag %s=%r to %s; using raw string.",
-            key, raw_value, info["type"],
-        )
-        return raw_value
 
 
 def _parse_cli_feature_flags() -> dict[str, Any]:
     """Parse --feature-flag key=value pairs from CLI args into a dict.
 
     Items without '=' default to the value 'true' (bare flag form).
+    Flags whose value cannot be coerced to the registered type are dropped
+    with a warning, so a typo like '--feature-flag some_bool=ture' does not
+    silently take effect as the wrong value.
     """
     result: dict[str, Any] = {}
     for item in getattr(args, "feature_flag", []):
@@ -70,7 +81,14 @@ def _parse_cli_feature_flags() -> dict[str, Any]:
             continue
         if not sep:
             raw_value = "true"
-        result[key] = _coerce_flag_value(key, raw_value.strip())
+        try:
+            result[key] = _coerce_flag_value(key, raw_value.strip())
+        except (ValueError, TypeError) as e:
+            info = CLI_FEATURE_FLAG_REGISTRY.get(key, {})
+            logging.warning(
+                "Could not coerce --feature-flag %s=%r to %s (%s); dropping flag.",
+                key, raw_value.strip(), info.get("type", "?"), e,
+            )
     return result
 
 

tests-unit/feature_flags_test.py

@@ -1,5 +1,7 @@
 """Tests for feature flags functionality."""
 
+import pytest
+
 from comfy_api.feature_flags import (
     get_connection_feature,
     supports_feature,
@@ -116,14 +118,26 @@ class TestCoerceFlagValue:
         assert _coerce_flag_value("unknown_flag", "true") == "true"
         assert _coerce_flag_value("unknown_flag", "42") == "42"
 
-    def test_failed_coercion_falls_back_to_string(self, monkeypatch):
+    def test_bool_typo_raises(self):
-        """Malformed values for typed flags must not crash; raw string is returned."""
+        """Strict bool: typos like 'ture' or 'yes' must raise so the flag can be dropped."""
+        with pytest.raises(ValueError):
+            _coerce_flag_value("show_signin_button", "ture")
+        with pytest.raises(ValueError):
+            _coerce_flag_value("show_signin_button", "yes")
+        with pytest.raises(ValueError):
+            _coerce_flag_value("show_signin_button", "1")
+        with pytest.raises(ValueError):
+            _coerce_flag_value("show_signin_button", "")
+
+    def test_failed_int_coercion_raises(self, monkeypatch):
+        """Malformed values for typed flags must raise; caller decides what to do."""
         monkeypatch.setitem(
             CLI_FEATURE_FLAG_REGISTRY,
             "test_int_flag",
             {"type": "int", "default": 0, "description": "test"},
         )
-        assert _coerce_flag_value("test_int_flag", "not_a_number") == "not_a_number"
+        with pytest.raises(ValueError):
+            _coerce_flag_value("test_int_flag", "not_a_number")
 
 
 class TestParseCliFeatureFlags:
@@ -145,6 +159,19 @@ class TestParseCliFeatureFlags:
         result = _parse_cli_feature_flags()
         assert result == {"valid": "1"}
 
+    def test_invalid_bool_value_dropped(self, monkeypatch, caplog):
+        """A typo'd bool value must be dropped entirely, not silently set to False
+        and not stored as a raw string. A warning must be logged."""
+        monkeypatch.setattr(
+            "comfy_api.feature_flags.args",
+            type("Args", (), {"feature_flag": ["show_signin_button=ture", "valid=1"]})(),
+        )
+        with caplog.at_level("WARNING"):
+            result = _parse_cli_feature_flags()
+        assert result == {"valid": "1"}
+        assert "show_signin_button" not in result
+        assert any("show_signin_button" in r.message and "drop" in r.message.lower() for r in caplog.records)
+
 
 class TestCliFeatureFlagRegistry:
     """Test suite for the CLI feature flag registry."""