Description:

All -debug packages have symlinks to their respective executables in usr/lib/debug/.build-id/, but those executables don't exist in the same package, only in the package they depend on. This results in dangling-symlink errors.

Using the contents of pacman-debug as an example:

usr/lib/debug/.build-id/9b/5469730b3d15d5631775a21648f0e8b55c73a2 -> ../../../../bin/pacman
usr/lib/debug/.build-id/9b/5469730b3d15d5631775a21648f0e8b55c73a2.debug -> ../../usr/bin/pacman.debug
usr/lib/debug/usr/bin/pacman.debug

Resulting namcap errors:

pacman-debug E: Symlink (usr/lib/debug/.build-id/9b/5469730b3d15d5631775a21648f0e8b55c73a2) points to non-existing ../../../../bin/pacman
...
pacman-debug W: Dependency included and not needed ('pacman')

This is a more specific case of  FS#45885 . I believe this one is easier to fix, while also affecting many packages. One could just detect debug packages and avoid checking them with namcap at all, or ignore all missing symlink errors inside usr/lib/debug.

The attached patch is one way to fix the issue - matching on ^usr/lib/debug/\.build-id/[0-9a-f/]+$

Additional info:
* namcap 3.2.7-2
* pacman 5.0.1-4
* devtools 20170304-1

Steps to reproduce:

1. Edit /etc/makepkg.conf
2. Change OPTIONS to have both strip and debug
3. makepkg
4. namcap *-debug*.pkg.tar.xz

That's the obvious way, which could be "fixed" by just not doing it, but this also appears when building packages with extra-x86_64-build:

1. Edit /usr/share/devtools/makepkg-x86_64.conf
2. Change OPTIONS to have both strip and debug
3. extra-x86_64-build

It checks all package files unconditionally so the error is always visible.


Full namcap output of pacman:

Checking pacman-5.0.1-4-x86_64.pkg.tar.xz
pacman W: Directory (var/cache/pacman/pkg) is empty
pacman W: Directory (var/lib/pacman) is empty
pacman W: Directory (usr/share/makepkg-template) is empty
pacman W: Directory (usr/share/libalpm/hooks) is empty
pacman W: Dependency bash included but already satisfied
pacman W: Dependency glibc included but already satisfied
Checking pacman-debug-5.0.1-4-x86_64.pkg.tar.xz
pacman-debug E: Symlink (usr/lib/debug/.build-id/9b/5469730b3d15d5631775a21648f0e8b55c73a2) points to non-existing ../../../../bin/pacman
pacman-debug E: Symlink (usr/lib/debug/.build-id/87/056dd7a9c0d8d803fee3d7144f167c75dd80f3) points to non-existing ../../../../bin/pactree
pacman-debug E: Symlink (usr/lib/debug/.build-id/3e/95729363335ec658d7b338f9da4436a348d071) points to non-existing ../../../../bin/pacsort
pacman-debug E: Symlink (usr/lib/debug/.build-id/59/bab096e306dc38d4d802e60bdeab28f47cdb46) points to non-existing ../../../../bin/cleanupdelta
pacman-debug E: Symlink (usr/lib/debug/.build-id/2e/5ddea30e5fcf1c60391624e86c252bb1a563e7) points to non-existing ../../../../bin/testpkg
pacman-debug E: Symlink (usr/lib/debug/.build-id/15/cd80a9279bfdd78008d2511e3ba3e9376f5198) points to non-existing ../../../../bin/vercmp
pacman-debug E: Symlink (usr/lib/debug/.build-id/ae/c8b1382957537899a2d5033c74079cc0f652c4) points to non-existing ../../../libalpm.so.10.0.1
pacman-debug W: Dependency included and not needed ('pacman')