panic log for some http API with negative table id

[lcwangchao]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

> curl "http://127.0.0.1:10080/db-table/-123"

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

> curl "http://127.0.0.1:10080/db-table/-123"
[schema:1146]Table which ID = -123 does not exist.

3. What did you see instead (Required)

> curl "http://127.0.0.1:10081/db-table/-123"
curl: (52) Empty reply from server

And a panic log in tidb

2024/03/22 10:42:52 http: panic serving 127.0.0.1:53256: runtime error: index out of range [-123]
goroutine 5202 [running]:
net/http.(*conn).serve.func1()
        /Users/wangchao/.gvm/gos/go1.21.0/src/net/http/server.go:1868 +0x118
panic({0x1081c98c0?, 0x140189ca198?})
        /Users/wangchao/.gvm/gos/go1.21.0/src/runtime/panic.go:920 +0x254
github.com/pingcap/tidb/pkg/infoschema.(*infoSchema).TableByID(0x140059bba00, 0xffffffffffffff85)
        /Users/wangchao/Code/pingcap/tidb/pkg/infoschema/infoschema.go:235 +0xfc
github.com/pingcap/tidb/pkg/server/handler/tikvhandler.DBTableHandler.ServeHTTP({0x1401179e5d0}, {0x10850bac0, 0x140189b6000}, 0x14017be9c00)
        /Users/wangchao/Code/pingcap/tidb/pkg/server/handler/tikvhandler/tikv_handler.go:1805 +0x238
github.com/gorilla/mux.(*Router).ServeHTTP(0x1401142cf00, {0x10850bac0, 0x140189b6000}, 0x14017be9c00)
        /Users/wangchao/.gvm/pkgsets/go1.21.0/global/pkg/mod/github.com/gorilla/mux@v1.8.0/mux.go:210 +0x254
net/http.(*ServeMux).ServeHTTP(0x140118b5900, {0x10850bac0, 0x140189b6000}, 0x14017be9a00)
        /Users/wangchao/.gvm/gos/go1.21.0/src/net/http/server.go:2514 +0x160
github.com/pingcap/tidb/pkg/server/internal/util.CorsHandler.ServeHTTP({{0x1084ed0e0, 0x140118b5900}, 0x140007de900}, {0x10850bac0, 0x140189b6000}, 0x14017be9a00)
        /Users/wangchao/Code/pingcap/tidb/pkg/server/internal/util/util.go:219 +0xe0
net/http.serverHandler.ServeHTTP({0x1401142f1d0}, {0x10850bac0, 0x140189b6000}, 0x14017be9a00)
        /Users/wangchao/.gvm/gos/go1.21.0/src/net/http/server.go:2938 +0x2a0
net/http.(*conn).serve(0x140189a4000, {0x108520c18, 0x140189a6050})
        /Users/wangchao/.gvm/gos/go1.21.0/src/net/http/server.go:2009 +0x155c
created by net/http.(*Server).Serve in goroutine 573
        /Users/wangchao/.gvm/gos/go1.21.0/src/net/http/server.go:3086 +0x7f8

4. What is your TiDB version? (Required)

[lcwangchao]

The reason is that we use % to compute the bucket index.

tidb/pkg/infoschema/builder.go

Line 973 in 5e19822

return int(tableID % bucketCount)

However, if the table id is negative, a negative index will be returned:

func main() {
	// will return -123
	fmt.Println(-123 % 512)
}

https://go.dev/play/p/XtiDd-ZyhWy