false positive in OrphanedFormatString check

[msridhar]

What version of Error Prone are you using?

Latest master

Does this issue reproduce with the latest release?

Yes

What did you do?

import java.util.Locale;
class OrphanedTest {
  public static void main(String[] args) {
    StringBuilder b = new StringBuilder().append("Hello ").append("%s");
    String formatted = String.format(Locale.getDefault(), b.toString(), "world");
    System.out.println(formatted);
  }
}

What did you expect to see?

No warning

What did you see instead?

OrphanedTest.java:4: warning: [OrphanedFormatString] String literal contains format specifiers, but is not passed to a format method
    StringBuilder b = new StringBuilder().append("Hello ").append("%s");
                                                                  ^
    (see http://errorprone.info/bugpattern/OrphanedFormatString)
1 warning

[awturner]

Thanks for the report.

This will be fixed in the next release. The check on StringBuilder.append has been tightened to only consider invocations which pass parameters (i.e. append(String, int, int) and append(char[], int, int)).