fixup

Author: realark

py/src/braintrust/__init__.py

@@ -51,13 +51,6 @@ def is_equal(expected, output):
 # Check env var at import time for auto-instrumentation
 import os
 
-from .env import validate_id_config as _validate_id_config
-
-
-# Fail fast on mutually-exclusive ID configuration (e.g. BRAINTRUST_OTEL_COMPAT
-# together with BRAINTRUST_LEGACY_UUID_IDS) as early as possible on import.
-_validate_id_config()
-
 
 if os.getenv("BRAINTRUST_INSTRUMENT_THREADS", "").lower() in ("true", "1", "yes"):
     try:

py/src/braintrust/context.py

@@ -6,7 +6,7 @@
 from dataclasses import dataclass
 from typing import Any
 
-from .env import BraintrustEnv, validate_id_config
+from .env import BraintrustEnv
 
 
 @dataclass
@@ -120,10 +120,6 @@ def get_context_manager() -> ContextManager:
         Braintrust-only context manager by default.
     """
 
-    # Fail fast if the ID configuration is inconsistent (belt-and-suspenders for
-    # the import-time check, in case env vars were mutated after import).
-    validate_id_config()
-
     # Check if OTEL should be explicitly enabled via environment variable
     if BraintrustEnv.OTEL_COMPAT.get(False):
         try:

py/src/braintrust/env.py

@@ -1,4 +1,5 @@
 import io
+import logging
 import math
 import os
 import shlex
@@ -8,6 +9,9 @@
 from typing import TypeVar, cast
 
 
+_logger = logging.getLogger(__name__)
+
+
 T = TypeVar("T")
 EnvValue = bool | float | int | str
 _Parser = Callable[[str], EnvValue | None]
@@ -168,37 +172,23 @@ class BraintrustEnv:
     LEGACY_UUID_IDS = EnvVar("BRAINTRUST_LEGACY_UUID_IDS", EnvParser.BOOL)
 
 
-class BraintrustEnvError(Exception):
-    """Raised when Braintrust environment variables are configured inconsistently."""
-
-
 def use_legacy_uuid_ids() -> bool:
     """Return True if the SDK should generate legacy UUID-based span/trace IDs.
 
     The default is OpenTelemetry-compatible hex IDs (16-byte trace id / 8-byte
     span id) with V4 span-component export. Setting BRAINTRUST_LEGACY_UUID_IDS
     opts back into UUID IDs with V3 export.
 
-    Note: BRAINTRUST_OTEL_COMPAT (which selects the OpenTelemetry context
-    manager) requires hex IDs, so it always forces hex regardless of this
-    function. The mutually-exclusive combination is rejected by
-    validate_id_config().
+    BRAINTRUST_OTEL_COMPAT (which selects the OpenTelemetry context manager)
+    requires hex IDs, so it always wins: if both it and BRAINTRUST_LEGACY_UUID_IDS
+    are set, legacy IDs are disabled and a warning is logged.
     """
-    validate_id_config()
+    legacy = BraintrustEnv.LEGACY_UUID_IDS.get(False)
     if BraintrustEnv.OTEL_COMPAT.get(False):
+        if legacy:
+            _logger.warning(
+                "BRAINTRUST_LEGACY_UUID_IDS is ignored because BRAINTRUST_OTEL_COMPAT "
+                "requires OpenTelemetry-compatible hex span IDs. Using hex IDs."
+            )
         return False
-    return BraintrustEnv.LEGACY_UUID_IDS.get(False)
-
-
-def validate_id_config() -> None:
-    """Fail fast on mutually-exclusive ID configuration.
-
-    BRAINTRUST_OTEL_COMPAT requires OpenTelemetry-compatible hex IDs, while
-    BRAINTRUST_LEGACY_UUID_IDS forces legacy UUID IDs. They cannot both be set.
-    """
-    if BraintrustEnv.OTEL_COMPAT.get(False) and BraintrustEnv.LEGACY_UUID_IDS.get(False):
-        raise BraintrustEnvError(
-            "BRAINTRUST_OTEL_COMPAT and BRAINTRUST_LEGACY_UUID_IDS are mutually "
-            "exclusive: OTEL compatibility requires hex span IDs, but legacy mode "
-            "forces UUID span IDs. Unset one of them."
-        )
+    return legacy

py/src/braintrust/test_env.py

@@ -2,15 +2,13 @@
 
 from .env import (
     BraintrustEnv,
-    BraintrustEnvError,
     EnvParser,
     EnvVar,
     parse_bool,
     parse_float,
     parse_int,
     parse_string,
     use_legacy_uuid_ids,
-    validate_id_config,
 )
 
 
@@ -168,20 +166,13 @@ def test_otel_compat_forces_hex(self, monkeypatch):
         monkeypatch.delenv("BRAINTRUST_LEGACY_UUID_IDS", raising=False)
         assert use_legacy_uuid_ids() is False
 
-    def test_conflicting_flags_raise(self, monkeypatch):
-        monkeypatch.setenv("BRAINTRUST_OTEL_COMPAT", "true")
-        monkeypatch.setenv("BRAINTRUST_LEGACY_UUID_IDS", "true")
-        with pytest.raises(BraintrustEnvError):
-            validate_id_config()
-        with pytest.raises(BraintrustEnvError):
-            use_legacy_uuid_ids()
+    def test_conflicting_flags_otel_wins_with_warning(self, monkeypatch, caplog):
+        # OTEL_COMPAT wins over LEGACY_UUID_IDS: legacy is disabled (hex IDs) and
+        # a warning is logged rather than raising.
+        import logging
 
-    def test_non_conflicting_flags_pass(self, monkeypatch):
-        # Each flag alone is fine.
         monkeypatch.setenv("BRAINTRUST_OTEL_COMPAT", "true")
-        monkeypatch.delenv("BRAINTRUST_LEGACY_UUID_IDS", raising=False)
-        validate_id_config()
-
-        monkeypatch.delenv("BRAINTRUST_OTEL_COMPAT", raising=False)
         monkeypatch.setenv("BRAINTRUST_LEGACY_UUID_IDS", "true")
-        validate_id_config()
+        with caplog.at_level(logging.WARNING):
+            assert use_legacy_uuid_ids() is False
+        assert any("BRAINTRUST_LEGACY_UUID_IDS" in r.message for r in caplog.records)

py/src/braintrust/test_id_gen.py

@@ -98,11 +98,13 @@ def test_id_get_env_var_legacy_uuid(reset_id_generator_state):
         assert_func(generator.get_trace_id())
 
 
-def test_otel_compat_and_legacy_uuid_conflict_raises(reset_id_generator_state):
+def test_otel_compat_wins_over_legacy_uuid(reset_id_generator_state):
+    # When both are set, OTEL_COMPAT wins: hex IDs are used (no raise).
     os.environ["BRAINTRUST_OTEL_COMPAT"] = "true"
     os.environ["BRAINTRUST_LEGACY_UUID_IDS"] = "true"
-    with pytest.raises(Exception):
-        id_gen.get_id_generator()
+    generator = id_gen.get_id_generator()
+    assert generator.share_root_span_id() is False
+    _assert_is_hex(generator.get_span_id())
 
 
 def _is_hex(s):