Re: [TopGit PATCH] hooks/pre-commit: check for cycles in dependencies

Hi Bert,

On Thu, Jun 04, 2009 at 10:41:13PM +0200, Bert Wesarg wrote:

Only newly added dependencies needs to be considered.  For each of these deps
check if there is a path from this dep to the current HEAD.

Use recursive_dep() for this task.  Even if recursive_dep() uses a DFS-like
traversal it will not run into an infty-loop if there would be a cycle, because

I'm not sure how understandable this is.  After some thinking I
understood DFS.  Up to now I thought infty is just the LaTeX macro name
for "infinity", but apart of this, is this really the right term here?
endless loop?

recursive_dep() takes .topdeps only from committed trees.  And it is required
that the committed dependency graph is acyclic.

I didn't check the implementation deeply.  But all in all I don't have
the usual warm and fuzzy feeling about it.  What happens during a remote
update if only the merged dependency graph has a cycle[1]?

Best regards
Uwe

[1] The question is a bit theoretic because remote updating is broken
here.  If you are my remote and changed a .topdep file, my update simply
discards your change.

-- 
Pengutronix e.K.                              | Uwe Kleine-König            |
Industrial Linux Solutions                    | http://www.pengutronix.de/  |