Does not build -- cannot find knowledge base when bootstraped with `prefix=$HOME/.local/`

[byu9]

Hi,

At least since v22.0.0, the bootstrap gprconfig installed into my prefix directory by the bootstrap program is having trouble locating its knowledge base. The bootstrap process successfully completed with --prefix=$HOME/.local. However, when running make all, the following error appears

$ which gprbuild
/home/jdoe/.local/bin/gprbuild

$ make
gprbuild -p -m   -j0 -XBUILD=production  gprbuild.gpr -XLIBRARY_TYPE=static -XXMLADA_BUILD=static
No valid configuration found
Generation of configuration files failed
GNAT-TEMP-000002.TMP:1:01: "project" expected
gprbuild: processing of configuration project "/tmp/GNAT-TEMP-000002.TMP" failed
make: *** [Makefile:95: build] Error 4

Attempts to run gprconfig fails with the following message

$ which gprconfig
/home/jdoe/.local/bin/gprconfig

$ gprconfig
No compilers found for target x86_64-pc-linux-gnu

Explicitly specifying knowledge base location to the bootstrap gprconfig appears to resolve issue

$ which gprconfig
/home/jdoe/.local/bin/gprconfig

$ gprconfig --db $HOME/.local/share/gprconfig
--------------------------------------------------
gprconfig has found the following compilers on your PATH.
Only those matching the target and the selected compilers are displayed.
   1. GNAT for Ada in /home/jdoe/.local/stow/gcc-11.2.0/bin/ version 11.2 (default runtime)
   2. GCC-ASM for Asm in /home/jdoe/.local/stow/gcc-11.2.0/bin/ version 11.2.0
   3. GCC-ASM for Asm in /usr/bin/ version 10.2.1
   4. GCC-ASM for Asm2 in /home/jdoe/.local/stow/gcc-11.2.0/bin/ version 11.2.0
   5. GCC-ASM for Asm2 in /usr/bin/ version 10.2.1
   6. GCC-ASM for Asm_Cpp in /home/jdoe/.local/stow/gcc-11.2.0/bin/ version 11.2.0
   7. GCC-ASM for Asm_Cpp in /usr/bin/ version 10.2.1
   8. LD for Bin_Img in /usr/bin/ version 2.35.2
   9. GCC for C in /home/jdoe/.local/stow/gcc-11.2.0/bin/ version 11.2.0
  10. GCC for C in /usr/bin/ version 10.2.1
  11. G++ for C++ in /home/jdoe/.local/stow/gcc-11.2.0/bin/ version 11.2.0
  12. G++ for C++ in /usr/bin/ version 10.2.1
Select or unselect the following compiler (or "s" to save):

[byu9]

UPDATE -- the problem appears to be caused by the symlinks of GNU Stow. Issue does not appear if gnat is directly installed into $HOME/.local instead of into $HOME/.local/stow then stowed into $HOME/.local.

[t-14]

We have no experience with stow. What file system structure do you get at destination location compared to pure install when using it?

[byu9]

Hi,

I think I'm sure at this point the problem is caused by the symlinks created by GNU Stow interfering with the build system and not by a bug in gprbuild

I attempted to use GNU Stow to support different compiler versions since I can unstow a compiler and restow a different version into my $PATH. My directory structure using GNU Stow is

• $HOME/.local
  • /share
    • /... (unrelated existing files & folders)
  • /stow
    • /gcc-11.2.0-native (configured with prefix=$HOME/.local)
    • /xmlada-22.0-native (configured with prefix=$HOME/.local)

Stow then computed the minimum number of symlinks that needed to be created in $HOME/.local to make it appear that the packages are installed directly into the parent $HOME/.local. However, when running the bootstrapped gprconfig, the program attempted to use the dereferenced compiler path ($HOME/.local/stow/gcc-11.2.0-native/share) to find the knowledge base. However, the knowledge base has been silently installed into the parent $HOME/.local/share/gprconfig by bootstrap. This is why the knowledge base was not found.

cd $HOME/.local/stow
stow xmlada-22.0-native gcc-11.2.0-native

For anyone encountering similar issues, the workaround is to call ./bootstrap --build to only build the packages, and then call DESTDIR=/tmp/gprbuild bootstrap --install to install the programs into a different location.

An improvement to the bootstrap program would be to make the --install option off by default to avoid silently installing files into locations outside the build directory.