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

2009/6/5 Uwe Kleine-König [off-list ref]:

Hi Bert,

Hi, Uwe,

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

quoted

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?

Yeah, 'endless loop' is the right term here.

quoted

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]?

I suspect the merge commit, which would introduce this cycle, will abort.

BTW: Do you have any infos or need help on your TopGit successor?

Bye,
Bert

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.

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