newSignatureFromCommitline panics during migration when tag author line does not contain timestamp

[as-com]

• Gitea version (or commit ref): starting in e232c49
• Git version: whatever comes with the Docker container
• Operating system: the BusyBox thing in the Docker container
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • Not relevant
• Log gist:

gogs_1                         | Oct 22 14:57:33 syslogd started: BusyBox v1.25.1
gogs_1                         | Oct 22 14:57:33 sshd[16]: Server listening on :: port 22.
gogs_1                         | Oct 22 14:57:33 sshd[16]: Server listening on 0.0.0.0 port 22.
gogs_1                         | 2017/10/22 14:57:43 [T] Custom path: /data/gitea
gogs_1                         | 2017/10/22 14:57:43 [T] Log path: /data/gitea/log
gogs_1                         | panic: runtime error: index out of range
gogs_1                         |
gogs_1                         | goroutine 1 [running]:
gogs_1                         | code.gitea.io/gitea/vendor/code.gitea.io/git.newSignatureFromCommitline(0xc4206c005a, 0xb, 0x5a6, 0x5ad, 0xc420150ff0, 0x6)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/code.gitea.io/git/signature.go:35 +0x457
gogs_1                         | code.gitea.io/gitea/vendor/code.gitea.io/git.parseTagData(0xc4206c0000, 0x66, 0x600, 0xc4206c0000, 0x66, 0x600)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/code.gitea.io/git/tag.go:54 +0x217
gogs_1                         | code.gitea.io/gitea/vendor/code.gitea.io/git.(*Repository).getTag(0xc4207a3d40, 0xf0daa9cfa4b95fa4, 0x8aa1a7de89906483, 0x8aa1a7de2a5c6328, 0xc42a5c6328, 0x0, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/code.gitea.io/git/repo_tag.go:65 +0x351
gogs_1                         | code.gitea.io/gitea/vendor/code.gitea.io/git.(*Repository).GetTag(0xc4207a3d40, 0xc4206ba00a, 0x12, 0x0, 0x564db1ecf8e0, 0xc4206d4760)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/code.gitea.io/git/repo_tag.go:89 +0x17f
gogs_1                         | code.gitea.io/gitea/models.pushUpdateAddTag(0xc4205802c0, 0xc4207a3d40, 0xc4206ba00a, 0x12, 0x564db273d740, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/models/update.go:114 +0xb6
gogs_1                         | code.gitea.io/gitea/models.SyncReleasesWithTags(0xc4205802c0, 0xc4207a3d40, 0xc4207a3d40, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/models/release.go:462 +0x502
gogs_1                         | code.gitea.io/gitea/models/migrations.releaseAddColumnIsTagAndSyncTags(0xc42029b4a0, 0x2, 0xc4201f4a38)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/models/migrations/v42.go:47 +0x245
gogs_1                         | code.gitea.io/gitea/models/migrations.(*migration).Migrate(0xc42030ab40, 0xc42029b4a0, 0xc4204c56d0, 0x1)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/models/migrations/migrations.go:53 +0x36
gogs_1                         | code.gitea.io/gitea/models/migrations.Migrate(0xc42029b4a0, 0x0, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/models/migrations/migrations.go:171 +0x3b8
gogs_1                         | code.gitea.io/gitea/models.NewEngine(0x564db18b26d0, 0xc, 0xc4204c57c8)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/models/models.go:270 +0x72
gogs_1                         | code.gitea.io/gitea/routers.GlobalInit()
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/routers/init.go:55 +0x310
gogs_1                         | code.gitea.io/gitea/cmd.runWeb(0xc4202e3400, 0x0, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/cmd/web.go:60 +0xb7
gogs_1                         | code.gitea.io/gitea/vendor/github.com/urfave/cli.HandleAction(0x564db174d000, 0x564db18b25a8, 0xc4202e3400, 0xc420188600, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/github.com/urfave/cli/app.go:471 +0xb9
gogs_1                         | code.gitea.io/gitea/vendor/github.com/urfave/cli.Command.Run(0x564db10aa8b1, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x564db10cda9c, 0x16, 0x0, ...)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/github.com/urfave/cli/command.go:191 +0xa74
gogs_1                         | code.gitea.io/gitea/vendor/github.com/urfave/cli.(*App).Run(0xc420073380, 0xc42000c060, 0x2, 0x2, 0x0, 0x0)
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/vendor/github.com/urfave/cli/app.go:241 +0x601
gogs_1                         | main.main()
gogs_1                         | 	/srv/app/src/code.gitea.io/gitea/main.go:44 +0x3a7

Description

I just tried to upgrade my Gitea server, but it kept on crashing with the above error message. I found that this appeared some time between 1.2.0rc2 and 1.2.0rc3, and I traced it to that specific commit.

I followed the code path to this error, and created the following Bash line to find which of my repositories was causing the issue:

for i in */*; do echo; echo $i; echo "======="; for t in $(git -C $i show-ref --tags | cut -f 1 -d " "); do if [ $(git -C $i cat-file -t $t) == "tag" ]; then git -C $i cat-file -p $t | grep "^tagger"; fi; done; done

and it turns out that a copy of the Quagga repository was causing the issue:

andrew/quagga.git
=======
tagger Denis Ovsienko <infrastation@yandex.ru> 1317300784 +0400
tagger Denis Ovsienko <infrastation@yandex.ru> 1325771815 +0400
tagger paul <paul>
tagger paul <paul>
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305620650 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305620770 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305620808 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305621324 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305621440 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305621066 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305620973 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305621511 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1305621602 +0100
tagger Chris Hall <chris.hall@highwayman.com> 1315351914 +0100
tagger Chris Hall <chris.hall@highwayman.com> 1315349362 +0100
tagger Chris Hall (GMCH) <chris.hall@highwayman.com> 1332158374 +0000
tagger Chris Hall <chris.hall@highwayman.com> 1332504450 +0000
tagger Chris Hall <chris.hall@highwayman.com> 1332505242 +0000
tagger Chris Hall <chris.hall@highwayman.com> 1336384768 +0100
tagger Chris Hall <chris.hall@highwayman.com> 1339165556 +0100
tagger Paul Jakma <paul@clubi.ie> 1131254104 +0000
tagger Paul Jakma <paul@quagga.net> 1143735361 +0100
tagger Paul Jakma <paul@quagga.net> 1143805065 +0100
tagger Paul Jakma <paul@quagga.net> 1143805186 +0100
tagger Paul Jakma <paul@quagga.net> 1147109393 +0100
tagger gdt <gdt>
tagger jardin <jardin>
tagger gdt <gdt>
tagger gdt <gdt>
tagger paul <paul>
tagger paul <paul>
tagger hasso <hasso>
tagger paul <paul>
tagger ajs <ajs>
tagger ajs <ajs>
tagger ajs <ajs>
tagger ajs <ajs>
tagger paul <paul>
[...]

GitHub seems to deal with one of these tags somewhat more gracefully: https://github.com/Quagga/quagga/releases/tag/zebra_org_20030428

For now, I've deleted the repository so the Gitea upgrade can proceed, but I think this code (https://github.com/go-gitea/gitea/blob/master/vendor/code.gitea.io/git/signature.go#L35) should be able to deal with a missing timestamp, especially since there are repositories out in the wild that have tags with author lines that are missing timestamps.

[lafriks]

I have submitted PR to fix this issue