FormatStringAnnotation
Invalid format string passed to formatting method.

Severity
ERROR
Has Fix?

The problem

Methods can be annotated with Error Prone’s @FormatMethod annotation to indicate that calls to this function should be treated similarly to String.format: One of the parameters is a ‘format string’ (the first String parameter or the only parameter annotated with @FormatString), and the subsequent parameters are used as format arguments to that format string.

For example:

@FormatMethod
void myLogMethod(@FormatString String fmt, Object... args) {}

// ERROR: 2nd format argument isn't a number
myLogMessage("My log message: %d and %d", 3, "has a message");

In order to avoid complex runtime issues when the format string part is dynamically constructed, leading to a mismatch between the arguments and format strings, we require that the ‘format string’ argument in calls to @FormatMethod-annotated methods be one of:

We will then check that the format string and format arguments match.

For more information on possible format string errors, see the documentation on the FormatString check.

The import for @FormatMethod is:

import com.google.errorprone.annotations.FormatMethod;

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings(“FormatStringAnnotation”) to the enclosing element.

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("FormatStringAnnotation") to the enclosing element.