"Branch name doesn't conform to GIT standards"

[EricCousineau-TRI]

Got bit by the issue captured in PR #7

Seeing as it's a bit delayed, I've made an issue, and will submit a PR that addresses the concerns.

What I ran into:

$ git config remote.upstream.url
hg::ssh://hg@bitbucket.org/osrf/sdformat
$ git fetch upstream
searching for changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 21 changes to 18 files
...
fatal: Branch name doesn't conform to GIT standards: refs/hg/upstream/tags/sdformat4_4.0.0~pre1
fast-import: dumping crash report to .git/fast_import_crash_6953
fatal: Error while running fast-import

[felipec]

You have to explain what is the issue.

I presume we do indeed need fix a corner case you are hitting, but it's hard to see what that corner case is.

When cloning https://felipec@bitbucket.org/osrf/sdformat this is what I get:

error: * Ignoring funny ref 'refs/tags/sdformat4_4.0.0~pre1' locally
error: * Ignoring funny ref 'refs/tags/sdformat4_4.0.0~pre2' locally
error: * Ignoring funny ref 'refs/tags/sdformat4_4.0.0~pre3' locally
error: * Ignoring funny ref 'refs/tags/sdformat4_4.3.0~pre1' locally
error: * Ignoring funny ref 'refs/tags/sdformat5_5.0.0~beta1' locally
error: * Ignoring funny ref 'refs/tags/sdformat5_5.0.0~beta2' locally
error: * Ignoring funny ref 'refs/tags/sdformat4_4.3.0~pre2' locally
error: * Ignoring funny ref 'refs/tags/sdformat6_6.0.0~pre1' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.0.0~pre1' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.0.0~pre2' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.0.0~pre3' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.0.0~pre4' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.0.0~pre5' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.1.0~pre1' locally
error: * Ignoring funny ref 'refs/tags/sdformat8_8.2.0~pre1' locally

But no crash. You want to avoid the crash, or get those tags?