"Access denied" errors are not handled properly

[fingolfin]

I just had an odd experienced where I did a "git push" via gitifyhg to a hg repository, and no errors were reported. Yet when I tried to pull the changes in a hg clone of the same repository, no changes arrived. I repeated this two more times (each time adding another commit), still nothing.

I finally went into .git/hg/*/clone and issued a "hg push" there, only to get this message"

pushing to ssh://hg@some.server/repos
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 3 changesets with 7 changes to 7 files
remote: error: pretxnchangegroup.access hook failed: mercurialserver.access: access denied for changeset XYZ
remote: transaction abort!
remote: rollback completed
remote: abort: mercurialserver.access: access denied for changeset XYZ

So it seems we should handle access denied errors, and inform the user accordingly. Instead of making it look as if everything succeeded.

[alexsydell]

I think taking care of this TODO would accomplish that: https://github.com/buchuki/gitifyhg/blob/master/gitifyhg/gitexporter.py#L102