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| author | Alexey Izbyshev <izbyshev@ispras.ru> | 2018-10-20 00:22:31 (GMT) |
|---|---|---|
| committer | Victor Stinner <vstinner@redhat.com> | 2018-10-20 00:22:31 (GMT) |
| commit | a2670565d8f5c502388378aba1fe73023fd8c8d4 (patch) | |
| tree | a9f3a5f8e2a123aaff4f27a94c33580f0216dccd /Lib/_pyio.py | |
| parent | 4acf6c9d4be77b968fa498569d7a1545e5e77344 (diff) | |
| download | cpython-a2670565d8f5c502388378aba1fe73023fd8c8d4.zip cpython-a2670565d8f5c502388378aba1fe73023fd8c8d4.tar.gz cpython-a2670565d8f5c502388378aba1fe73023fd8c8d4.tar.bz2 | |
bpo-32236: open() emits RuntimeWarning if buffering=1 for binary mode (GH-4842)
If buffering=1 is specified for open() in binary mode, it is silently
treated as buffering=-1 (i.e., the default buffer size).
Coupled with the fact that line buffering is always supported in Python 2,
such behavior caused several issues (e.g., bpo-10344, bpo-21332).
Warn that line buffering is not supported if open() is called with
binary mode and buffering=1.
Diffstat (limited to 'Lib/_pyio.py')
| -rw-r--r-- | Lib/_pyio.py | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/Lib/_pyio.py b/Lib/_pyio.py index 01ef5b7..b8975ff 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -198,6 +198,11 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, raise ValueError("binary mode doesn't take an errors argument") if binary and newline is not None: raise ValueError("binary mode doesn't take a newline argument") + if binary and buffering == 1: + import warnings + warnings.warn("line buffering (buffering=1) isn't supported in binary " + "mode, the default buffer size will be used", + RuntimeWarning, 2) raw = FileIO(file, (creating and "x" or "") + (reading and "r" or "") + |