Add PySys_FormatStdout and PySys_FormatStderr functions #53808

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1. vstinner commented on Aug 14, 2010

   

   vstinner

   on Aug 14, 2010

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   For my work bpo-9425 (Rewrite import machinery to work with unicode paths), I need a function to write unicode strings to sys.stderr (especially to write messages on import in verbose mode). Attached patch creates PySys_FormatStdout() and PySys_FormatStderr(). It's the same idea than the new function PyErr_WarnFormat() vs PyErr_WarnEx() (added by r83976): similar API but use PyUnicode_FromFormatV().

   PySys_FormatStdout() and PySys_FormatStderr() don't truncate the output message. PySys_WriteStdout() and PySys_WriteStderr() truncate the output because they use a static buffer of 1001 bytes, but I don't know if it is an implementation choice (to avoid bugs?) or just a limitation of the implementation.

   About the patch:

   • rename mywrite() to sys_write() to use a less generic name (it helps debugging)
   • in sys_write(): don't call PyErr_Clear() if the second call to sys_pyfile_write() fails, because it is useless. fputs() doesn't care to Python exceptions and the exception state is restored just after the call to fputs()
   • sys_format() encodes the message to utf-8 on sys_pyfile_write_unicode() failure because utf-8 is able to encode all unicode characters (except unicode surrogates). Use an error handler to escape surrogates may avoid encode errors, but it's not important here because sys_pyfile_write_unicode() should not fail. sys_pyfile_write_unicode() knows better how to handle surrogate characters (sys.stderr uses backslashreplace error handler by default).

   For bpo-9425, I only need PySys_FormatStderr(), but I added also PySys_FormatStdout() just to be consistent with PySys_Write*() and because it only costs a few line of code.
2. vstinner

   added

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   topic-unicode

   on Aug 14, 2010
3. vstinner commented on Aug 16, 2010

   

   vstinner

   on Aug 16, 2010

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   Commited as r84094 to 3.2.
4. vstinner

   closed this as completedon Aug 16, 2010
5. ezio-melotti

   transferred this issue fromon Apr 10, 2022