Fix crash when cwd is deleted

[yo-main]

Should solve #2527

I didn't figure out how to set an error on the editor from some places.

Where is was crashing before, it now relies on the scratch buffer instead.
In some other places (not related to buffer, like the open command or the global search ), I was able to generate a message or rely on the default value of the PathBuffer.

Let me know any improvements/suggestions you can see, I'll be more than happy to correct them :)

[yo-main]

Thanks for reviewing !
Changes have been done accordingly

[the-mikedavis]

This is looking good, just needs the clippy lints fixed

[yo-main]

should be fine now 🤞

[pascalkuthe]

Sorry for being a bit late here. I put off reviewing this because I thin this is actually a bit more subtle to solve. IMO it's really unfortunate that get_cwd can fail (if the directory doesn't exist anymore) ideally I would still like to obtain the path and then fail when attempting any IO (which can always fail so no special handeling required).

This PR often uses unwrap_or_default or other suboptimal fallback strategies. I would really like to avoid this as that can lead to other issues.

I think a better approach would be to track CWD in helix internally. Just store the path in a static that is intalized on startup (and if we fail to acquire the cwd on startup we can just exit with an error). The only way CWD can change at runtime is by using the command so we only need to update the static in that command.

[the-mikedavis]

It looks like we will need to do some path expansion. mkdir tmp and then either cargo r tmp or cargo r and then :cd tmp: The directory will change correctly but current_working_dir will return tmp and not the full path. This messes up consumers like file_picker that are expecting an expanded path.

I'm not totally sure where this expansion should belong. We could move

helix/helix-core/src/path.rs

Lines 88 to 97 in c33795e

	pub fn get_canonicalized_path(path: &Path) -> std::io::Result<PathBuf> {
	let path = expand_tilde(path);
	let path = if path.is_relative() {
	std::env::current_dir().map(|current_dir| current_dir.join(path))?
	} else {
	path
	};
	Ok(get_normalized_path(path.as_path()))
	}

over to helix-loader and call it from set_current_working_dir. That would shift around some dependencies and code between helix-core and helix-loader but might be the cleaner option. Or we could require that each caller of set_current_working_dir passes in an absolute path (maybe a debug_assert could work here). What do you think?

[pascalkuthe]

It looks like we will need to do some path expansion. mkdir tmp and then either cargo r tmp or cargo r and then :cd tmp: The directory will change correctly but current_working_dir will return tmp and not the full path. This messes up consumers like file_picker that are expecting an expanded path.

I'm not totally sure where this expansion should belong. We could move

helix/helix-core/src/path.rs

Lines 88 to 97 in c33795e

	pub fn get_canonicalized_path(path: &Path) -> std::io::Result<PathBuf> {
	let path = expand_tilde(path);
	let path = if path.is_relative() {
	std::env::current_dir().map(|current_dir| current_dir.join(path))?
	} else {
	path
	};
	Ok(get_normalized_path(path.as_path()))
	}

over to helix-loader and call it from set_current_working_dir. That would shift around some dependencies and code between helix-core and helix-loader but might be the cleaner option. Or we could require that each caller of set_current_working_dir passes in an absolute path (maybe a debug_assert could work here). What do you think?

Good catch! .we can actually use dunce::cannonicolize derctly here I think. That canonicalization function only makes a difference if the path doesn't currently exits (wich is not the case here since the working directory must exist). I wouldn't want to move all the code over but just adding that one extra dependency seems fine to me

[yo-main]

updated ! thanks for spotting :)

[the-mikedavis]

For the two changes here we will probably want some feedback:

if !cwd.exists() {
    editor.set_error("Current working directory does not exist");
    return;
}

since the file_picker_in_current_directory won't show any files and global_search won't be able to find any matches if the cwd doesn't exist.

[the-mikedavis]

Looks good 👍

I like the "deleted" message in the show_current_directory too, that's a nice touch