[Bug d/93038] New: Missing dependencies in depfile for imported files at compilation time

[bouvier.pierrick at yahoo dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93038

            Bug ID: 93038
           Summary: Missing dependencies in depfile for imported files at
                    compilation time
           Product: gcc
           Version: 9.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: d
          Assignee: ibuclaw at gdcproject dot org
          Reporter: bouvier.pierrick at yahoo dot fr
  Target Milestone: ---

Dear GDC developers,

when gdc is used to generate a depfile (make format), if code uses feature
import(file), file is not reported in list of dependencies.

I tested with gdc-{8,9,10}.

# cat main.d
import std.stdio;
void main() { writeln(import(".bashrc")); }
# gdc main.d -J. -MMD
# cat main.deps
main.o: main.d

Until version 8, gdc has support for fdeps option. Problem is that format used
(dictated by dmd) is useless in Make/Ninja build systems.
# gdc-8 -fdeps main.d -J.
...
depsFile main (main.d) : .bashrc (/home/user/.bashrc)
...

I build my code using meson project, which relies on depfiles created by
compiler. Thus, a dependency is missed.

Would that be possible to add file imported at compilation time in list of
dependencies? Technically, I think this file is not read at same time than
other import, but I still think that would be a great add to gdc.

Thank you,
Pierrick