Dune: How to add a dependency on one executable to another?

Ecosystem
1

Hi everyone.

I have a Dune project consisting of two executables, each defined with the executable stanza in their own subdirectories.

One of the executables uses the Bos library to invoke the other executable; it’s a “driver” of that executable.

Suppose the first exectuable is called emit and the second executable is called package.

I’d like to ensure that emit has been been built by Dune before I try to invoke it with package (otherwise, I might get a “file not found” error, or changes to emit might not be visible when I invoke package).

As far as I can tell, I cannot add arbitrary dependencies to the executable stanza of Dune.

Is there a solution? Perhaps I’m going about this the wrong way?

2

Perhaps you can define a rule with both executables as dependencies to do what you want?

Best wishes,
Nicolás

3

Another option is to extract the needed functionality from emit into a library, and then call out to the library using package.

4

See https://github.com/ocaml/dune/issues/3499 (Allow dependencies for executables).

The work-around I use is to copy the executable and then install the copy. The copying rule adds the dependency. e.g.

5

Thank you for the GitHub link and for reporting it! It describes the issue exactly. I’ll take a look at the workaround in the mean time.