Question

Is there a way to have a file that is modified / touched whenever the WC is updated to a new revision? Or, as the second-best option, whenever svn update is executed?

Here’s the motivation: I want to have the SVN revision number inside my executable. So I have to run SubWCRev as part of the build. The output file of SubWCRev is re-created every time, even if the revision number has not changed. This means that the exe is linked on every build, even if nothing has changed. I want it to be linked only as needed.

Answer 1

1. Get the SubWCRev output into a temporary file
2. Compare this file to the current revision-number file
3. Overwrite it with the temp file only if the two are different
4. Delete the temporary file

You might even be able to do this with a .bat file (using fc). Something like…

REM ***UNTESTED*** FC temp.rev curr.rev | FIND 'FC: no dif' > nul  IF NOT ERRORLEVEL 1 COPY /Y temp.rev curr.rev DEL temp.rev 

Edit: As an aside, you can do this in Mercurial by making the rev-number-file depend on .hg/dirstate.