Panic in pgxpool healthcheck

[ihasdapie]

Describe the bug

I ran into a panic in runtime in my https://github.com/Permify/permify deployment inside this library. I haven't ever seen permify panic before, and saw that the panic was in the healthcheck in this library and so figured it might be worthwhile reporting. I have no clear way of reproducing this issue.

/home/runner/go/pkg/mod/github.com/jackc/pgx/[email protected]/pgxpool/pool.go:273 +0x370
created by github.com/jackc/pgx/v5/pgxpool.NewWithConfig in goroutine 1
/home/runner/go/pkg/mod/github.com/jackc/pgx/[email protected]/pgxpool/pool.go:275 +0x32
github.com/jackc/pgx/v5/pgxpool.NewWithConfig.func3()
/home/runner/go/pkg/mod/github.com/jackc/pgx/[email protected]/pgxpool/pool.go:415 +0xdd
github.com/jackc/pgx/v5/pgxpool.(*Pool).backgroundHealthCheck(0xc0001486c0)
/home/runner/go/pkg/mod/github.com/jackc/pgx/[email protected]/pgxpool/pool.go:430 +0x34
github.com/jackc/pgx/v5/pgxpool.(*Pool).checkHealth(0xc0001486c0)
/home/runner/go/pkg/mod/github.com/jackc/pgx/[email protected]/pgxpool/pool.go:449 +0x45
github.com/jackc/pgx/v5/pgxpool.(*Pool).checkConnsHealth(0xc0001486c0)
/home/runner/go/pkg/mod/github.com/jackc/puddle/[email protected]/pool.go:592 +0x1bc
github.com/jackc/puddle/v2.(*Pool[...]).AcquireAllIdle(0x19e1260)
goroutine 109 [running]:
[signal SIGSEGV: segmentation violation code=0x1 addr=0x38 pc=0x1073b5c]
panic: runtime error: invalid memory address or nil pointer dereference

To Reproduce

Expected behavior
no panic

Actual behavior
a panic

Version

• Go: $ go version -> 1.24.0
• PostgreSQL: PostgreSQL 15.7 on aarch64-unknown-linux-gnu, compiled by gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-6), 64-bit
• pgx 5.7.2, puddle 2.2.2

Additional context
Add any other context about the problem here.