docs/bugpattern/AnnotateFormatMethod.md

This method passes a pair of parameters through to `String#format`, but the
enclosing method wasn't annotated `@FormatMethod`. Doing so gives compile-time
rather than run-time protection against malformed format strings. Consider
annotating the format string with
`@com.google.errorprone.annotations.FormatString` and the method with
`@FormatMethod` to allow compile-time checking for well-formed format strings.

```java
static void log(String format, String... args) {
  Log.w(format, args);
}

void frobnicate(int a, int b) {
  if (a < b) {
    // Whoops: didn't provide enough format args.
    log("%s < %s", a);
  }
}
```

```java
@FormatMethod
static void log(@FormatString String format, String... args) {
  Log.w(format, args);
}
```

WARNING: There's a very high chance that manual intervention will be required
after applying this fix, either due to existing uses of the method not passing
in valid format strings, or methods which delegate to this one requiring the
`@FormatMethod` annotation as well. Please ensure that everything depending on
this code still compiles after applying.