[CMake] Version embedding - how to cause a command when make is run?

[David Cole]

As Alan points out, you shouldn't trust the output of "svn info" as
gospel unless you also verify that "svn status" gives you *empty*
output.

In the case that Alan identifies of trying to track down where a bug
was introduced, a quick svn status check would show you which files
were *not* up to date with respect to the svn info output... (local
modifications, local additions/deletions and files unknown to svn are
all reported by svn status)

HTH,
David


On 10/5/07, Alan W. Irwin <irwin at beluga.phys.uvic.ca> wrote:
> On 2007-10-05 14:28+0100 Atwood, Robert C wrote:
>
> >
> > >> From: Alan W. Irwin (on cmake list)
> >
> >>> Yes, [svnversion] is the whole point! It is much easier
> >> than using individual
> >>> revision nubmers for each file.
> >>
> >> Although not nearly as informative.  I just tried svnversion,
> >> and it only
> >> gives a range of Revision numbers for the source tree. That's
> >> a non-unique
> >> way of identifying source trees
> >
> > How so?
> > As I understand the range is the range of project revision nubmers at
> > which the most recent changes for files has occurred.
> >
> > But I am fairly new to SVN after switching from CVS, so I would like to
> > know how identical svnversion output from different source trees would
> > come about? Maybe I should ask that on the svn list as well .
>
> If you confine yourself to committing, then that (AFAIK) always increments
> the maximum number in the range so you should be okay for that use case.
> However, suppose you use svn update --revision because one of your mass
> commits introduced a bug and you are systematically trying old revisions of
> files to see which is responsible.  (I have been there and done that!) To
> take a concrete but simple example, suppose you have five files which all
> have 3 possibilities (1,2,3) for the revision number. IOW, each file changed
> for each revision. Then using svn update --revision you can create 3^5 = 243
> different combinations of revision numbers for the various source files in
> your source tree, and svnversion will identify all such different source
> trees identically.  In fairness, you might not use svn update --revision
> that often so svnversion will normally give you a unique identifier, but as
> the concrete example shows, not always, particularly when exploring old
> revisions to help track down a bug.
>
> Alan
> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state implementation
> for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
> package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
> Linux Links project (loll.sf.net); and the Linux Brochure Project
> (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
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