cinaps fails with Error: Unable to resolve symlink

[smuenzel]

When creating a dune project with cinaps 1.2 and a file to run cinaps on, @runtest will fail with

Error: Unable to resolve symlink

on the file we apply cinaps to. cinaps 1.0 works fine.
@hhugo suspects it's related to #6176

Steps to reproduce

git clone git@github.com:smuenzel/sandbox2.git
cd sandbox2
dune build @runtest

Note: this is a repo with just one ml file and dune files, cut down from the original repo where I had the issue

Specifications

$ dune --version
3.7.0
$ ocamlopt.opt --version
4.14.1
$ head -n1 /etc/os-release
PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"

Additional information

• Link to gist with verbose output (run dune with the --verbose flag):
• https://gist.github.com/smuenzel/6b84b94a500fa148a40a3b814215c6f8

[Alizter]

I am unable to reproduce your example. I just get:

 |  $ git clone git@github.com:smuenzel/sandbox2.git
+|  Cloning into 'sandbox2'...
 |  $ cd sandbox2
 |  $ dune build @runtest
+|  File "bindings/boolector.ml", line 1, characters 0-0:
+|  Error: Files _build/default/bindings/boolector.ml and
+|  _build/default/bindings/boolector.ml.cinaps-corrected differ.
+|  [1]
 |  $ exit

[hhugo]

I can reproduce the issue on my machine. @Alizter, you seem to be using some cram tests, could it explain the difference ?

[Alizter]

Yes, I can confirm the issue outside of a cram test.

[Alizter]

OK, so the issue here is that the build action fails, but we want to print the diff. However since the action is sandboxed, the original failed file gets cleaned up before we can diff it. This is at least what I expect is happening. I haven't been able to reproduce this behaviour with user defined actions.

Edit: actually scratch that. The sandbox is still there, but for some reason the original source file is missing.

Also FTR --sandbox none will get ignored, so that can't be a workaround.

[Alizter]

OK the issue was that the action we had for the cinaps rule didn't record the source files hence they were missing from the sandbox. I have fixed this and tested that the example here now works (fails) correctly.

#7618

[smuenzel]

Also FTR --sandbox none will get ignored, so that can't be a workaround.

Do you know why this happens? Seems kind of bad if it can't be used to avoid problems with the sandbox.

[Alizter]

@smuenzel some actions in Dune rules use sandboxing in a critical way where disabling it would break the rules. The sandbox option is really only for sandboxing declared by the user where it might not be critical.