Header variable bug src/as-validator-issue-tag.h

[hholst80]

/~https://github.com/ximion/appstream/blame/221ed8e10b59061d07f6ac01a624ed1e86b3686f/src/as-validator-issue-tag.h#L39

This is a variable defined in a header file. It needs to go into a compilation unit and only one.

[hholst80]

The problem is in the tests. The library and the test itself will both define the same symbol.

tests/test-validate.c:#include "as-validator-issue-tag.h"
docs/gen-valtag-sections.c:#include "as-validator-issue-tag.h"
docs/meson.build:    '../src/as-validator-issue-tag.h',
compose/asc-globals.c:#include "as-validator-issue-tag.h"
src/as-validator.c:#include "as-validator-issue-tag.h"

[ximion]

How are you compiling AppStream? This conflict does not seem to happen with any compiler we test with, and shouldn't since the symbol is hidden in the library, so the linker shouldn't see it.

I have also been unable to reproduce the issue.

[hholst80]

You will likely only be able to trigger this if you attempt to compile with --prefer-static or --default-library=static (or =both).

[hholst80]

I do not know about fancy link level magic like symbol hiding, but from a C code perspective the original post is still valid: We cannot have non-local variables with the same name in two compilation units. In the test we need to refer to the variable as extern or normal C linkage will not work.

Proposed workaround: Can we use a simple #ifdef for the header file, if it is included from a test unit? So, in the test case, its defined as extern, otherwise no action required, keep old definition.