Problem building crate with libadalang

General
1

I tried to play a bit with libadalang, so I created a binary crate followed by:

with libadalang
alr build

but I got the following build errors:

gpr.adb:1757:13: error: ambiguous expression (cannot resolve "To_Lower")
gpr.adb:1757:13: error: possible interpretation at a-chahan.ads:273
gpr.adb:1757:13: error: possible interpretation at s-casuti.ads:99
gpr.adb:1757:32: error: ambiguous expression (cannot resolve "To_Lower")
gpr.adb:1757:32: error: possible interpretation at a-chahan.ads:273
gpr.adb:1757:32: error: possible interpretation at s-casuti.ads:99

   compilation of gpr-conf.adb failed

The compilation error looks identical to the one in this 4-year-old post: https://www.reddit.com/r/ada/comments/ohflj5/problem_with_gnatcoll_gmp_and_alire/, but I could not find a solution or a proper bug report.

Any ideas? My alire version is 2.0.1.

2

Now tried it with alire 2.1.0. Building and running using alr build and alr run now works, but compiling from GNAT Studio gives an error: gpr.gpr 30:4 value “unix” is illegal for typed string “Target”

3

Hello, what version of libadalang are you building?

Can you give us the output of alr show --solve.

4

The dependencies as shown in the output of alr show -- solve are:

Dependencies (direct):
libadalang^25.0.0
Dependencies (solution):
adasat=25.0.0
gnat=14.2.1 (gnat_native)
gnatcoll=25.0.0
gnatcoll_gmp=25.0.0
gnatcoll_iconv=25.0.0
langkit_support=25.0.0
libadalang=25.0.0
libgmp=6.2.1
libgpr=25.0.0
libgpr2=25.0.0
prettier_ada=25.0.0
vss=25.0.0
xmlada=25.0.0
Dependencies (graph):
draht_gen=0.1.0-dev → libadalang=25.0.0 (^25.0.0)
gnatcoll=25.0.0 → gnat=14.2.1 (gnat_native) (>=13)
gnatcoll=25.0.0 → libgpr=25.0.0 (~25.0.0)
gnatcoll_gmp=25.0.0 → gnatcoll=25.0.0 (~25.0.0)
gnatcoll_gmp=25.0.0 → libgmp=6.2.1 (*)
gnatcoll_iconv=25.0.0 → gnatcoll=25.0.0 (~25.0.0)
langkit_support=25.0.0 → adasat=25.0.0 (^25)
langkit_support=25.0.0 → gnatcoll=25.0.0 (^25)
langkit_support=25.0.0 → gnatcoll_gmp=25.0.0 (^25)
langkit_support=25.0.0 → gnatcoll_iconv=25.0.0 (^25)
langkit_support=25.0.0 → prettier_ada=25.0.0 (^25)
libadalang=25.0.0 → gnatcoll=25.0.0 (^25)
libadalang=25.0.0 → gnatcoll_gmp=25.0.0 (^25)
libadalang=25.0.0 → gnatcoll_iconv=25.0.0 (^25)
libadalang=25.0.0 → langkit_support=25.0.0 (^25)
libadalang=25.0.0 → libgpr2=25.0.0 (^25)
libgpr=25.0.0 → gnat=14.2.1 (gnat_native) (/=2020)
libgpr=25.0.0 → xmlada=25.0.0 (~25.0.0)
libgpr2=25.0.0 → gnat=14.2.1 (gnat_native) (>=14)
libgpr2=25.0.0 → gnatcoll=25.0.0 (~25.0.0)
libgpr2=25.0.0 → gnatcoll_gmp=25.0.0 (~25.0.0)
libgpr2=25.0.0 → gnatcoll_iconv=25.0.0 (~25.0.0)
prettier_ada=25.0.0 → gnatcoll=25.0.0 (^25)
prettier_ada=25.0.0 → vss=25.0.0 (^25)
vss=25.0.0 → gnat=14.2.1 (gnat_native) (>=11 & <2000)
xmlada=25.0.0 → gnat=14.2.1 (gnat_native) (>=11)

5

I now could get around the error by hacking the gpr.gpr file.

6

Do you an “OS” environment variable set? Because it seems like it.

7

No, that variable does not exist. I have no idea where that “unix” value comes from.

8

Are you using GNAT Studio?

9

Yes. The problem only occurred when compiling from GNAT Studio. alr build worked after switching to Alire 2.1.0.

1 Like
10

In GNAT Studio there’s a panel to set scenario variables. It’s possible that the variable was set in this panel and that’s what was causing the issue.

11

Indeed, there is a scenario variable OS with the value “unix”. So that seems to be the cause.

I’m also getting a warning in GNAT Studio: “Could not display all variables in the scenario view: a scenario variable named ‘EXTERNALLY_BUILT’ appears more than once in the project tree.”