On Mon, Nov 05, 2012 at 02:15:53PM +0100, Marc Espie wrote: > Turns out python is stupid enough to store path+timestamp in its compiled > *.pyc files to know when to recompile.
The "auto-recompile everything which is out of date" feature is ingenious but there are at least two different ways of implementing it. One way is to check the timestamps on X.py and X.pyc; if the latter is older than the former, recompile, and (try to) cache the output to X.pyc. [This is how Converge works, if anyone cares.] Judging by your comment, Python stores the timestamp in the file itself (probably for portability/performance reasons) rather than checking the timestamp from the filesystem. [I can't remember off-hand, nor can I remember how PyPy does it either.] I assume the only people who are having pkg_delete problems are running a Python program as root? If so, in one sense, they're the lucky ones. The unlucky ones would then be those running as non-root where the "is X.py newer than X.pyc" check fails, forcing a recompilation, but which can't then save out a cached file. So every time they run Python they'll be paying a recompilation cost for such files. The question this raises in my mind is the following. During an update, can the timestamp of X.py be updated, but not X.pyc? If so, then I think that would be a problem that pkg_update needs to fix: timestamps (particularly the relative timestamps of files i.e. "X is older than Y") are an important piece of meta-data. If not, then it might be possible to make a case to the Python developers that rather than storing timestamps in the pyc file, they should simply read it from the filesystem. That would mean that both X.py and X.pyc could be updated, but providing X.pyc is newer than X.py, Python would not try to write out a cached file. Laurie -- Personal http://tratt.net/laurie/ The Converge programming language http://convergepl.org/ https://github.com/ltratt http://twitter.com/laurencetratt
