[Enesuygurs]

Problem

Since #640, reraise=True surfaces the exception that triggered a TryAgain instead of the TryAgain itself. It does this with raise cause... from None, which mutates that exception: its __cause__ is reset to None and __suppress_context__ is forced to True. The traceback then loses whatever led to the error.

from tenacity import Retrying, TryAgain, stop_after_attempt

def load_config():
    try:
        raise OSError("disk unavailable")
    except OSError as e:
        raise KeyError("config") from e

def call():
    try:
        load_config()
    except KeyError:
        raise TryAgain

Retrying(stop=stop_after_attempt(2), reraise=True)(call)
# KeyError('config'), but __cause__ is None: the OSError and the
# "direct cause" section are gone from the traceback.

The same applies to an implicit context (raise KeyError inside except OSError): the "During handling of the above exception" section is suppressed. Retrying the same function without TryAgain keeps the chain intact, because that path (raise self.last_attempt.result()) does not use from None.

Fix

Drop from None in RetryError.reraise() and raise the exception as is. Its own __cause__ and __context__ are left untouched, which matches the non-TryAgain path. Behaviour is otherwise unchanged: the same exception type and instance are raised, and a bare TryAgain still reraises TryAgain. A reno release note is included.

Note: #730 edits the line two above this one in the same hunk. Whichever of the two lands second will need a trivial rebase.

Tests

I added regression tests in tests/test_tenacity.py for the explicit chain (raise ... from e) and the implicit context, and one in tests/test_asyncio.py for the explicit chain with AsyncRetrying. They fail without the change and pass with it.

• pytest: 188 passed, 15 subtests passed
• ruff check . / ruff format --check .: pass
• mypy: no issues found in 19 source files
• sphinx-build -W doctest and html: pass

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