Hidden folders are ignored in source_tree dep

[SUPERCILEX]

Expected Behavior

If I have a file onchip/.cargo/config.toml and include it with (source_tree onchip), it should be part of the sources.

Actual Behavior

It's impossible to get dune to see the file. Even explicitly saying (file onchip/.cargo/config.toml) doesn't work.

Error: No rule found for soft/onchip/.cargo/config.toml

Specifications

• Version of dune (output of dune --version): 3.6.1

[rgrinberg]

Did you try doing (dirs :standard .cargo) in the directory containing the .cargo dir?

[SUPERCILEX]

That worked, thanks! It should be documented somewhere with the word hidden so people can find it.

[Lupus]

I've also stumbled upon this behavior. After trial and error I intuitively managed to fix it by adding (data_only_dirs .cargo) stanza, went on to report this and found this issue. This case definitely needs better documentation, I've tried searching for "hidden files" but no results. Also dune could probably hint me when complaining about no rule for file that file actually exists in the source tree, but in a hidden folder so maybe I need to add corresponding stanza to my dune file. That would be really user-friendly.

[Alizter]

@emillon we should document hidden files for 3.8.

[emillon]

it's important to fix but I wouldn't say we should delay 3.8 on this.

[gridbugs]

I also just ran into this problem (also with .cargo) and was confused/frustrated and eventually just renamed it to "dot_cargo" and used a dune rule to rename it to ".cargo" before building. Does anyone know the original motivation for ignoring hidden files? Would it be reasonable to print a warning when a file is ignored in this manner which doesn't match some list of known files to ignore (e.g. .git)?

[Alizter]

I think it was just not very well thought out. I believe that we discussed at some point to weaken this restriction to specific cases like .git.

[gridbugs]

I propose we create a page of dune gotchas. I feel like dune often surprises me with its opinions and I spend time thinking I'm doing something wrong only to learn that I've encountered a quirk of the build system. We could list all the things about dune that those less familiar with it (like me) have found surprising and link to open issues to address the quirks that we'd like to change in the future and include explanations of the quirks that we want to keep. I think it would be useful for new adopters who hit some unexpected behaviour to have a place to look to see if it's well-known unexpected behaviour. I recently made a non-trivial dune-based project from scratch for the first time and at several points was surprised by something dune did or didn't do. I'd be happy to start such a document while these memories are still fresh.

[Alizter]

I think this was one of the motivations with the FAQ page.

[gridbugs]

Ah cool. I have some updates to make then!

[Alizter]

IINM :standard does not include _* or .* however you can glob all directories with *. So it should be possible to do (dirs * \ .git) though I haven't tried it.