Crash in infoschema.FormatTiDBVersion

[secsys-go]

Bug Report

We used the Fuzz engine to modify some Test(TestFormatVersion) data, and then the following crash appeared. We hope to get the help of the developer to confirm whether it is a real bug.

1. Minimal reproduce step (Required)

Simplified Test Code

infoschema.FormatTiDBVersion("5.7.2Delta;5-TiDB-", true)

2. What did you expect to see? (Required)

Test Passed

3. What did you see instead (Required)

Crash Log

panic: runtime error: index out of range [0] with length 0 [recovered]
	panic: runtime error: index out of range [0] with length 0

goroutine 125 [running]:
testing.tRunner.func1.2({0x373e4a0, 0xc0005bae70})
	/home/gogen/.local/go/src/testing/testing.go:1209 +0x24e
testing.tRunner.func1()
	/home/gogen/.local/go/src/testing/testing.go:1212 +0x218
panic({0x373e4a0, 0xc0005bae70})
	/home/gogen/.local/go/src/runtime/panic.go:1038 +0x215
github.com/pingcap/tidb/infoschema.FormatTiDBVersion({0x3939818, 0x12}, 0x0)
	/home/gogen/workspace/gowork/src/topproj/tidb/infoschema/tables.go:1615 +0x179
github.com/pingcap/tidb/infoschema_test.FuzzTestFormatVersion({0xc000436800, 0x22, 0x200})
	/home/gogen/workspace/gowork/src/topproj/tidb/infoschema/tables_test.go_TestFormatVersion_test.go:27 +0x9b

4. What is your TiDB version? (Required)

9c4f94d

[YangKeao]

Though it seems that the FormatTiDBVersion actually expected some specific format of versions, I prefer to keep this issue, as this problem is really annoying in some cases (sometimes I manually modified this function to return a constant value, to make it run on some platforms...).

Maybe we could have a more convincing FormatTiDBVersion. At least return unknown or nightly when the version is not expected 🤔