`A18-0-1`: Consider more than just the file name when identifying use of C standard libraries

[nicolaswill]

Affected rules

• A18-0-1

Description

The query for this rule reports any use of headers with file names the same as a prohibited C standard library header. This can cause false positives if the included file is not from a C standard library implementation but just happens to have the same name as a C standard library header.

There's no certain way to determine whether an include is of a C Standard Library header file, because the files themselves are not universally distinguishable, so we will need to consider some heuristics for identification.

As an initial idea, we could only report cases where:

• The #include specifies no file path (e.g. filename = i.getIncludeText().substring(1, i.getIncludeText().length() - 2))
• And where the target file is not within the source location (e.g. not exists(i.getIncludedFile().getRelativePath())

Example

$ cat lib/example.h 
#ifndef LIB_EXAMPLE_H_
#define LIB_EXAMPLE_H_

#endif

$ cat test.cpp 
#include "lib/example.h"  // A18-0-1 reported here
#include <iostream>