[texworks] external read-access causes TeXWorks to revert open file to old version

[Stefan Löffler]

Hi,

Am 2010-10-25 22:36, schrieb Stefan Müller:
> Another thing I just recognized: In a "positive run" (i.e. where the
> problem occurs) TW prints (beside others) the following debug messages:
>
> Loading: "/dir/to/my/file.tex"
> Loading: "/dir/to/my"
> ...
> Loading: "/dir/to/my"
> Changed: "/dir/to/my/file.tex"
> Loading: "/dir/to/my/file.tex"

Hm, this is strange. I guess there should be one "Changed" line
preceding each "Loading" line when directories are involved.

> Is it correct, that sometimes the directory and sometimes the file is
> loaded?

Yes, this is correct. Directories are also watched, because changes to
the directory (rename, deletion, ...) can also (implicitly) cause
changes to the file. This may, however, also be related to your problem
(see below). Note that in this case, no actual load action should occur
(which is checked below the qDebug() line you added, though).

I think I mentioned this before, but your problem may be related to a
race condition. Just as Tw detects a change (to either the directory or
the file), further change-detection is disabled for the duration of the
processing. So if mercurial changes the file/directory, Tw may register
this and start its processing (doing lots of checks, remembering where
you were in the file, etc.). Then, it loads the file. Then it tries to
restore the previous state. And only then it re-enables the file system
checker. So if mercurial changes the file twice for some reason (or
changes the directory first possibly with the last committed version of
the file and then replaces the file), Tw may pick up the wrong version.
To verify this, could you put the following line just after the `[1094]
qDebug() << "Changed:" << curFile;` line:
qDebug() << fileModified;
This should print the file modification time during each reload. Could
you then compare these to the timestamp output by `ls -l --full-time` on
the command line in both a "normal" and a "positive" run? This could
give us an indication whether Tw picks up a different version of the file.

HTH
Stefan