Re: Using GPRbuild in GitLab build pipeline to build against a library that's not installed

[Anh Vo <anhvofrcaus@gmail.com>]

On Friday, May 1, 2020 at 3:39:41 PM UTC-7, Trescott Jensen wrote:
> On Friday, May 1, 2020 at 1:19:43 PM UTC-6, onox wrote:
> > On Friday, May 1, 2020 at 4:05:46 PM UTC+2, Trescott Jensen wrote:
> > > I've been reading the GPRbuild documentation trying to learn how to do this, but I'm not finding what I need. (Or maybe I'm not recognizing it. My experience is with the Green Hills build tools.)
> > > 
> > > I'm playing with the basic GtkAda "hello world" example program.
> > > 
> > > I can build it on my local box (Linux), but the build pipeline on GitLab fails on the with "gtkada" line in the gpr file. I recognize that this is because the environment that the build pipeline is running in does not have the library installed.
> > > 
> > > I have tried including the gtkada git repository as a sub-module in my git repository and building it with my project, but this leads to more dependency issues, when I don't really need to build the library in the first place.
> > > 
> > > I've tried including the compiled library in my git repository and copying/installing the files into the build pipeline's environment, but the build process does not have the needed permissions. (I didn't expect this to work.)
> > > 
> > > So, this leaves me wanting to tell GPRbuild to look in a non-standard location to find the library to build against.
> > > 
> > > How do I specify a path for libraries?
> > > 
> > > Am I going about this the wrong way? Is there a better way?
> > 
> > You can specify the search paths with ADA_PROJECT_PATH (multiple paths separated by a colon). The search paths that gprbuild will use can be displayed with gnatls -v. Library (.so files) paths can be set with LD_LIBRARY_PATH.
> 
> I forgot to mention that I had tried using LD_LIBRARY_PATH, but I didn't know about ADA_PROJECT_PATH or gnatls -v.
> 
> I used gnatls -v on my local box:
> GNATLS 9.3.0
> Copyright (C) 1997-2019, Free Software Foundation, Inc.
> 
> Source Search Path:
>    <Current_Directory>
>    /usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/adainclude
> 
> 
> Object Search Path:
>    <Current_Directory>
>    /usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/adalib
> 
> 
> Project Search Path:
>    <Current_Directory>
>    /usr/x86_64-pc-linux-gnu/lib/gnat
>    /usr/x86_64-pc-linux-gnu/share/gpr
>    /usr/share/gpr
>    /usr/lib/gnat
> 
> 
> Which lead to finding /usr/lib/gnat/gtkada.gpr Which showed me what files I had missed before and cleared up a lot of confusion about how to use some of the options in the gpr file.
> 
> I added all the GtkAda files to my git repository so that the relative paths would match the gtkada.gpr file and added the ADA_PROJECT_PATH and LD_LIBRARY_PATH to the environment.
> 
> *The build pipeline now see GtkAda.*
> 
> Now I have to resolve a GNAT version discrepancy between the library and the pipeline. But for that one I know what to do...
> 
> Thank you Onox for your guidance. You have save me a lot of time and pain.

I am glad that Onox helped you out. If you have read the "GPRbuild and GPR Companion Tools User’s Guide", you would have spotted this information. By the way, ADA_PROJECT_PATH environment is used for compatibility. The prefered one is GPR_PROJECT_PATH.

Gpr build document can be found at AdaCore site, https://docs.adacore.com/live/wave/gprbuild/html/gprbuild_ug/gprbuild_ug.html. In addition, it also comes with GNAT, and it can be invoked thru GPS Help menu as Help -> GNAT -> Gprbuild and GNAT Project Files.

Anh Vo