Issue 34672: '%Z' strftime specifier never works with musl (original) (raw)

With the musl C library, one has failures like this:

====================================================================== FAIL: test_strptime (test.test_time.TimeTestCase)

Traceback (most recent call last): File "/buildbot/buildarea/3.x.ware-alpine/build/Lib/test/test_time.py", line 273, in test_strptime time.strptime(strf_output, format) ValueError: time data '' does not match format '%Z' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/buildbot/buildarea/3.x.ware-alpine/build/Lib/test/test_time.py", line 276, in test_strptime (format, strf_output)) AssertionError: conversion specifier '%Z' failed with '' input.

The root problem is that time.strptime('%Z', time.gmtime()) won't work—it returns an empty string—even though time.gmtime() will probably have a valid tm_zone field. This is because musl has a safety mechanism where it refuses to process a tm_zone entry unless it produced the string. (See https://git.musl-libc.org/cgit/musl/commit/?id=d78be392e144c338f58ce6a51d82c859126c137d.)

As a partial workaround, I propose we check whether an incoming time.struct_time instance has an tm_zone member equal to tzname[0] or tzname[1], and place one of those global strings into the C-level tm struct if they do match.