Error Reporting groups errors which are considered to have the same root cause.
Before Error Reporting evaluates any error for grouping, it decides the following:
- On App Engine standard environment, errors logged with a severity lower than
- Stack frames which are not owned by the user are ignored (for instance, those that belong to public libraries).
- Any repeating sequence of one or more stack frames is replaced by a single occurrence of that sequence.
- Compiler-introduced methods and symbols are removed.
When the system is evaluating errors, it follows these general patterns:
- Exceptions are grouped together if they have the same exception type and similar stacks.
- The stack trace is ignored for exceptions that are typically unrelated to the source location where they occur.
- Errors without an exception stack are grouped together if they were created by
the same log statement, approximated by the source location it was reported
Specifically, the following grouping rules are applied in this order:
|Error type||Grouped by|
|Errors caused by a general problem in the environment.
For example, App Engine specific problems:
|Grouped by exception type.|
|Errors with a stack trace. In the case of nested exceptions, the
innermost exception is considered.
runtime error: index out of range package1.func1() file1:20 package2.func2() file2:33
|Grouped by exception type and the 5 top-most frames.|
|Errors without a stack trace, but with a message.
runtime error: index out of range func1()
|Grouped by message and (if present) function name. Only the first 3 literal
tokens of the message are considered. In the example to the left, these