9db3a5869e
This is python bug https://bugs.python.org/issue13146. Fixed since python 3.4. It makes pyc creation atomic, preventing a race condition. The patch has been rebased on our deterministic build patch. It wasn't backported to python 2.7 because there was a complaint about changed semantics. Since files are now created in a temporary directory and then moved, symlinks will be overridden. See https://bugs.python.org/issue17222. That is an edge-case however. Ubuntu and debian have backported the fix in 2013 already, making it mainstream enough for us to adopt.
42 lines
1.3 KiB
Diff
42 lines
1.3 KiB
Diff
diff --git a/Lib/py_compile.py b/Lib/py_compile.py
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index 978da73..3559eb9 100644
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--- a/Lib/py_compile.py
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+++ b/Lib/py_compile.py
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@@ -120,16 +120,27 @@ def compile(file, cfile=None, dfile=None, doraise=False):
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return
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if cfile is None:
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cfile = file + (__debug__ and 'c' or 'o')
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- with open(cfile, 'wb') as fc:
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- fc.write('\0\0\0\0')
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- if "DETERMINISTIC_BUILD" in os.environ:
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+ # Atomically write the pyc/pyo file. Issue #13146.
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+ # id() is used to generate a pseudo-random filename.
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+ path_tmp = '{}.{}'.format(cfile, id(cfile))
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+ try:
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+ with open(path_tmp, 'wb') as fc:
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fc.write('\0\0\0\0')
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- else:
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- wr_long(fc, timestamp)
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- marshal.dump(codeobject, fc)
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- fc.flush()
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- fc.seek(0, 0)
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- fc.write(MAGIC)
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+ if "DETERMINISTIC_BUILD" in os.environ:
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+ fc.write('\0\0\0\0')
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+ else:
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+ wr_long(fc, timestamp)
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+ marshal.dump(codeobject, fc)
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+ fc.flush()
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+ fc.seek(0, 0)
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+ fc.write(MAGIC)
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+ os.rename(path_tmp, cfile)
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+ except OSError:
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+ try:
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+ os.unlink(path_tmp)
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+ except OSError:
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+ pass
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+ raise
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def main(args=None):
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"""Compile several source files.
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