Exception in dune build when Unix domain socket in directory

[verbosemode]

The dune build command raises the following exception when a Unix domain socket file is in the same directory:

Error: exception Sys_error("fail.sock: No such device or address")

Reproduction

1.) Create a new directory

2.) Create a "dune' file with the following content

(executable
 (name unixsocket)
 (libraries unix))

3.) Create a "dune-project" file with the following content

(lang dune 2.2)

4.) Create an empty .ml file without code.

echo "" > unixsocket.ml

5.) Create a Unix domain socket file (press ctrl+c to quit netcat)

nc -Ul fail.sock

6.) Run "dune build"

Specifications

• Version of dune (output of dune --version): 2.2.0
• Version of ocaml (output of ocamlc --version): 4.09.0
• Operating system (distribution and version): Debian GNU/Linux 10 (buster)

Additional information

https://gist.github.com/verbosemode/7e7374309df5d6436a3400737fd8b3ad

[verbosemode]

I ran some more tests.

Creating a device file results in the same issue.

sudo mknod mydevicefile c 0 0

When I'm creating a FIFO with "mkfifo testfifo", dune build just gets stuck.

[ghost]

Raising is unfortunate indeed. What behaviour would you expect? The best I can think of is making Dune ignore such files.

[Leonidas-from-XIV]

I think plainly ignoring such "special files" (except symlinks) might be the best idea, since it is unlikely that a build system can have a sensible interaction with e.g. a device file.

[verbosemode]

Raising is unfortunate indeed. What behaviour would you expect? The best I can think of is making Dune ignore such files.

I agree with @Leonidas-from-XIV here. Ignoring non-regular files might be a good idea. A warning message and asking the user to clean up the directory would be too noisy and not so user friendly I guess.

[ghost]

That seems fine to me