Add env: argument to custom_target, run_target, run_command

[Salamandar]

The env argument available for tests would be really useful for custom_targets too.

index_html_tmp = custom_target('index.html.tmp',
  input : [ babl_html_dump, ],
  output: [ 'index.html.tmp', ],
  command: [ 'bash', '-c',
    'BABL_PATH="' + join_paths(meson.build_root(), 'extensions') +'"'
    + ' ' + babl_html_dump.full_path()
  ],
  capture: true,
)

would be changed to

index_html_tmp = custom_target('index.html.tmp',
  input : [ ],
  output: [ 'index.html.tmp', ],
  command: [ babl_html_dump ],
  env: [ 'BABL_PATH="' + join_paths(meson.build_root(), 'extensions') +'"' ],
  capture: true,
)

[TingPing]

command: [ 'bash', '-c',
'BABL_PATH="' + join_paths(meson.build_root(), 'extensions') +'"'
+ ' ' + babl_html_dump.full_path()
],

In the short term use env not bash -c for obvious reasons.

command: [
  find_program('env'),
  'BABL_PATH=' + join_paths(meson.build_root(), 'extensions'),
  babl_html_dump
]

[Salamandar]

Great, that also allows to split the commands from a single string to multiple strings. (and even use '&&' !)
That's still a workaround though.

[jtojnar]

Apparently, the issue is that ninja does not have a way to set environment variables in cross-platform way: #541 (comment)

[gdesmott]

Dup of #266

[Salamandar]

@gdesmott Not exactly, mine is about run_target too.

[marc-h38]

Not exactly, mine is about run_target too.

Looking at what's been done already, it seems a different github issue/PR is needed for every command.

[rossburton]

Had a quick look at this. For the simple case of run_target gaining an env argument, would a sensible approach be to extend commandrunner to take --env=FOO=BAR and simply pass the added environment variables to the invocation in the ninja generator. The commandrunner can then do the same as run_command to construct the final environment:

meson/mesonbuild/interpreter.py

Line 169 in 33d8220

child_env = os.environ.copy()

[eli-schwartz]

Duplicate of #266, solved by #8235 and #8305