Move cfg nil check from RenewManagedCertificates to getConfig

[joga84]

getConfig checks cfg.certCache so cfg can never be nil inside of getConfig or it can crash with:
invalid memory address or nil pointer dereference

[mholt]

Thanks, nice find. This is probably the result of a refactor where the call to GetConfigForCert() was wrapped by getConfig().

Did you happen to encounter this panic? Or did you just notice it with some inspection/tooling?

[joga84]

Did you happen to encounter this panic? Or did you just notice it with some inspection/tooling?

This was triggering a panic once a week or so on a system with many domains. Hope to now figure out why the config ends up nil in the first place:

{
    "level":"error",
    "ts":1234560000.1111111,
    "logger":"tls.cache.maintenance",
    "msg":"panic",
    "cache":"0xc0004c0e00",
    "error":"runtime error: invalid memory address or nil pointer dereference","stack":"goroutine 66 [running]:
                github.com/caddyserver/certmagic.(*Cache).maintainAssets.func1()
                    github.com/caddyserver/[email protected]/maintain.go:50 +0x85
                panic({0x17a0d80?, 0x2bbd170?})
                    runtime/panic.go:792 +0x132
                github.com/caddyserver/certmagic.(*Cache).getConfig(_, {{{0xc08bbb9dd0, 0x2, 0x2}, {0x192fae0, 0xc0900c23c0}, {0x0, 0x0, 0x0}, {0x0, ...}, ...}, ...})
                    github.com/caddyserver/[email protected]/cache.go:368 +0xbe
                github.com/caddyserver/certmagic.(*Cache).RenewManagedCertificates(0xc0004c0e00, {0x1ee11f0, 0xc00061e000})
                    github.com/caddyserver/[email protected]/maintain.go:121 +0x325
                github.com/caddyserver/certmagic.(*Cache).maintainAssets(0xc0004c0e00, 0x0)
                    github.com/caddyserver/[email protected]/maintain.go:71 +0x348
                created by github.com/caddyserver/certmagic.NewCache in goroutine 1
                    github.com/caddyserver/[email protected]/cache.go:110 +0x185
           "
}