René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"git_revwalk_hide assertion failure during fetch","articleBody":"### Version of libgit2 (release number or SHA1)\r\n0.27.0\r\n\r\nI was debugging libgit2/pygit2/issues/787 where fetch was failing.\r\n\r\nI found a bug in foreach_reference_cb, this is the backtrace:\r\n\r\n```\r\n#1  0x00007ffff2f885f5 in foreach_reference_cb (reference=0x105cc40, payload=0xfdf1d0) at .../libgit2/libgit2-0.27.0/src/transports/local.c:514\r\n#2  0x00007ffff2f5419e in git_reference_foreach (repo=0xf85ae0, callback=0x7ffff2f885c8 \u003cforeach_reference_cb\u003e, payload=0xfdf1d0)\r\n    at .../libgit2/libgit2-0.27.0/src/refs.c:746\r\n#3  0x00007ffff2f88814 in local_download_pack (transport=0xffc520, repo=0xf85ae0, stats=0xfd25b0, progress_cb=0x7ffff7fe7fc0, progress_payload=0x7ffff0ad96d8)\r\n    at .../libgit2/libgit2-0.27.0/src/transports/local.c:575\r\n#4  0x00007ffff2effd9d in git_fetch_download_pack (remote=0xfd24e0, callbacks=0xfd12f8) at .../libgit2/libgit2-0.27.0/src/fetch.c:148\r\n#5  0x00007ffff2f5885c in git_remote_download (remote=0xfd24e0, refspecs=0x0, opts=0xfd12f0) at .../libgit2/libgit2-0.27.0/src/remote.c:932\r\n#6  0x00007ffff2f589d2 in git_remote_fetch (remote=0xfd24e0, refspecs=0x0, opts=0xfd12f0, reflog_message=0x0)\r\n```\r\n\r\n`foreach_reference_cb` passes `git_reference_target(reference)`\r\nhttps://github.com/libgit2/libgit2/blob/d9007dc8520942763a21e4058dfa8f159f3e3c56/src/transports/local.c#L510-L514\r\n\r\nto `git_revwalk_hide`\r\n\r\nhttps://github.com/libgit2/libgit2/blob/d9007dc8520942763a21e4058dfa8f159f3e3c56/src/revwalk.c#L103-L107\r\n\r\nbut `git_reference_target` can return `NULL`. so `assert(walk \u0026\u0026 oid)` will fail.\r\n\r\nhttps://github.com/libgit2/libgit2/blob/d9007dc8520942763a21e4058dfa8f159f3e3c56/src/refs.c#L372-L380\r\n\r\nIn my case, `type = GIT_REF_SYMBOLIC`, and `symbolic = \"refs/remotes/origin/master\"`","author":{"url":"https://github.com/RazerM","@type":"Person","name":"RazerM"},"datePublished":"2018-04-05T09:07:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/4612/libgit2/issues/4612"}