Function parse

internal/godebug/godebug.go:206–237

parse parses the GODEBUG setting string s, which has the form k=v,k2=v2,k3=v3. Later settings override earlier ones. Parse only updates settings k=v for which did[k] = false. It also sets did[k] = true for settings that it updates. Each value v can also have the form v#pattern, in which case the GOD

(did map[string]bool, s string)

// in which case the GODEBUG is only enabled for call stacks
// matching pattern, for use with golang.org/x/tools/cmd/bisect.
func parse(did map[string]bool, s string) {
	// Scan the string backward so that later settings are used
	// and earlier settings are ignored.
	// Note that a forward scan would cause cached values
	// to temporarily use the ignored value before being
	// updated to the "correct" one.
	end := len(s)
	eq := -1
	for i := end - 1; i >= -1; i-- {
		if i == -1 || s[i] == ',' {
			if eq >= 0 {
				name, arg := s[i+1:eq], s[eq+1:end]
				if !did[name] {
					did[name] = true
					v := &value{text: arg}
					for j := 0; j < len(arg); j++ {
						if arg[j] == '#' {
							v.text = arg[:j]
							v.bisect, _ = bisect.New(arg[j+1:])
							break
						}
					}
					lookup(name).value.Store(v)
				}
			}
			eq = -1
			end = i
		} else if s[i] == '=' {
			eq = i
		}
	}
}

type runtimeStderr struct{}