Jbuilder warning, aliases must not have targets

Learning
1

Hi, I’ve been trying to make a jbuild file for tests (alcotest), but before running them I want to copy one file into the same directory with the tests.exe. I described an executable part in the jbuild, and below an alias to run tests with “jbuilder build @_build/default/src/runtest”. The alias part looks like

(alias
 ((name runtest)
  (deps (tests.exe))
  (action
    (progn
      (copy path/file1.txt file2.txt)
      (run ${<})))
 )
)

Everything works fine, but there is a warning saying “Warning: Aliases must not have targets, this target will be ignored. This will become an error in the future.”. It points out to the file2.txt. How it can be fixed?

2

you can setup the copy rule on the side:

(alias
 ((name runtest)
  (deps (tests.exe))
  (action (run ${<})))

(rule (copy path/file1.txt file2.txt))

(Note that you should probably specify file2.txt as a dependency of running tests.exe).

A few users have been bitten by this, maybe we should just allow it.

3

Hi. This solution worked fine with jbuilder, but once I updated to dune the build process fails with “Error: path outside the workspace:”. I’ve updated all parts to dune according to https://dune.readthedocs.io/en/latest/migration.html.
Is there a way to add to the workspace the whole project folder or maybe only path/file1.txt? “path/file1.txt” is located in the root folder of the project.

4

@alrev, could you provide the dune file that causes this error?

5 
(executables
  (names project1 tests)
    (libraries
      core_kernel
      core
      async
      alcotest-async)
  (preprocess (pps ppx_jane))
  (modes native)
  (modules project1 module1 module2 tests)
)

(alias
 (name runtest)
  (deps tests.exe test_file.txt)
  (action (run ./tests.exe))
)

(rule (copy ../../../test_data/test_file.txt test_file.txt))

The folder structure is
project1
project1/project1.opam
project1/src
project1/test_data

I want to copy somehow files from “test_data” folder to the “_build/default/src/” before running “tests.exe”. Maybe there is a better approach? Thanks for the help.

6

Can you try:

(rule (copy ../test_data/test_file.txt test_file.txt))

? Source files are automatically copied from the source tree to the _build/default directory on demand, and only dune itself is allowed to do that.

1 Like
7

It works.
By having 3 “…” in the ../../../test_data/test_file.txt I thought we go back to the root project folder out of the _build/default/src, which worked somehow with jbuilder. Now I see the test_data folder in the _build/default.
Thanks for the explanation.

8

It indeed used to work with jbuilder, however in Dune we added the possibility to change the build directory (via a command line option or environment variable) so we made such paths forbidden.