FrameBridge 0.3.4 corresponding-source release

Snapshot assembled only from the signed corresponding-source archive.
Source archive SHA-256: db91a270cdefc4be79056ed38a0b4a16747e1ab130592645eac40fa3809809df

source/target-vendors/cp312/sse_starlette/_utils.py

@@ -0,0 +1,37 @@
+import sys
+from contextlib import contextmanager
+from typing import Generator
+
+# Divergence #3 (see sse_starlette/sse.py module docstring): vendored copy of
+# starlette._utils.collapse_excgroups. We do not import the upstream version
+# because it lives in a private (underscore-prefixed) Starlette module, and
+# the pinned floor (starlette>=0.41.3) makes that import surface unstable.
+#
+# Behaviour: AnyIO v4 wraps task-group failures in an ExceptionGroup; this
+# helper unwraps single-exception groups so user middleware sees the bare
+# exception (matching pre-v4 anyio and Starlette's StreamingResponse).
+# Solution per https://anyio.readthedocs.io/en/stable/migration.html
+
+has_exceptiongroups = True
+if sys.version_info < (3, 11):
+    try:
+        from exceptiongroup import BaseExceptionGroup  # noqa: F401
+    except ImportError:
+        has_exceptiongroups = False
+
+
+@contextmanager
+def collapse_excgroups() -> Generator[None, None, None]:
+    try:
+        yield
+    except BaseException as exc:
+        if has_exceptiongroups:
+            # `ty` does not narrow BaseExceptionGroup.exceptions; the runtime
+            # contract is identical to starlette._utils.collapse_excgroups.
+            while isinstance(exc, BaseExceptionGroup) and len(exc.exceptions) == 1:  # ty: ignore[unresolved-attribute]
+                exc = exc.exceptions[0]  # ty: ignore[unresolved-attribute]
+
+        raise exc
+
+
+__all__ = ["collapse_excgroups"]