[issue5128] compileall: consider ctime

[Martin von Gagern]

New submission from Martin von Gagern <Martin.vGagern at gmx.net>:

When trying to decide whether or not a given file needs to be
recompiled, the inode creation time should be taken into account along
with the file modification time.

Scenario: Suppose you have three times, A < B < C < D. At time A, you
package version 1 of foo.py. At time B, you package version 2. At time C
you install version 1 onto some system, and byte-compile it for all
users. Therefore foo.py has mtime A and ctime C, and foo.pyc has both
mtime C. At time D you delete foo.py from version 1 and install version
2. Then you byte-compile it without force. At that time, foo.py has
mtime B (because that was when it was packaged) but ctime D (because
that was when the file was created). foo.pyc has mtime C (because that
was when it was last modified). The current comparison compares only
mtimes, sees C > B, and skips foo.py. With this patch in place, it will
check for C > max(B, D), which is not the case, and thus recompile foo.c.

In other words, max(st_mtime, st_ctime) can be interpreted as the last
time a file at a given path was changed, either through modification of
its contents (mtime) or deletion followed by recreation (ctime).
Installation systems that overwrite files without deleting them before
still are in the same trouble as before, but all others will benefit
from this.

See also: http://bugs.gentoo.org/256953

----------
components: Library (Lib)
messages: 80939
nosy: gagern
severity: normal
status: open
title: compileall: consider ctime
type: feature request
versions: Python 2.5

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue5128>
_______________________________________