v0.1.11 harden logging lifecycle, sanitization, and formatter edge cases

compat/structured_format_test.go

@@ -0,0 +1,54 @@
+package compat
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestParseFormatKeepsArgumentAssociation(t *testing.T) {
+	for _, tc := range []struct {
+		format string
+		args   []any
+		want   []any
+	}{
+		{"prefix %s id=%d", []any{"alice", 42}, []any{"msg", "prefix alice id=42"}},
+		{"id=%[2]d name=%[1]s", []any{"alice", 42}, []any{"msg", "id=42 name=alice"}},
+		{"id=%d suffix", []any{42}, []any{"msg", "suffix", "id", 42}},
+		{"user=%s id=%d", []any{"alice", 42}, []any{"user", "alice", "id", 42}},
+		{"id=%d %s", []any{42, "tail"}, []any{"msg", "id=42 tail"}},
+		{"id=%*d", []any{4, 42}, []any{"msg", "id=  42"}},
+		{"literal %% id=%d", []any{42}, []any{"msg", "literal % id=42"}},
+	} {
+		t.Run(tc.format, func(t *testing.T) {
+			if got := parseFormat(tc.format, tc.args); !reflect.DeepEqual(got, tc.want) {
+				t.Fatalf("got %#v, want %#v", got, tc.want)
+			}
+		})
+	}
+}
+
+func FuzzParseFormat(f *testing.F) {
+	for _, format := range []string{"id=%d", "%s id=%d", "%%id=%d", "id=%[1]s"} {
+		f.Add(format, "value")
+	}
+	f.Fuzz(func(t *testing.T, format, value string) {
+		if len(format) > 1024 {
+			t.Skip()
+		}
+		fields := parseFormat(format, []any{value})
+		if len(fields)%2 != 0 {
+			t.Fatalf("odd fields %#v", fields)
+		}
+		for i := 0; i < len(fields); i += 2 {
+			if _, ok := fields[i].(string); !ok {
+				t.Fatalf("non-string key %#v", fields)
+			}
+		}
+		if len(fields) == 2 && fields[0] == "msg" {
+			if fields[1] != fmt.Sprintf(format, value) {
+				t.Fatal("fallback changed message")
+			}
+		}
+	})
+}