rg 13.0.0 breaks integration with NeoVim

[datanoise]

I am using vim-grepper NeoVim plugin that uses new jobstart api to start ripgrep as a background process and uses callback functions to read the produced output. With the new ripgrep version 13.0.0, this plugin stopped working.

I have found that commit 020c545 cause this problem. Just as the comment to this commit suggested, the ripgrep completely blocks forever without reporting any output. Reverting this change, fixes the problem.

Is there a way to provide the command line option to disable checking for sockets in this method?

[BurntSushi]

I'm not keen on adding flags to change stdin detection unless there is absolutely no other way.

I suppose the obvious question here is this: why is ripgrep being started with a socket attached to stdin that shouldn't be searched?

I tried to answer this question myself by looking at the plugin's source, but couldn't really make sense of it.

[datanoise]

I believe that is how background job processing is implemented in NeoVim. NeoVim uses libuv with the event loop processing, which AFAIK is socket based.

[BurntSushi]

Thanks for responding, but it doesn't really help my understanding here. Why is it attaching a socket to stdin in the first place?

I understand this is probably frustrating since ripgrep changed its behavior and caused a breakage here, but before I'm willing to implement a kludge or break somebody's else's patch, I need to understand whether the plugin itself is working correctly or not. It eould be very surprising to me if "attach a socket to stdin" was an unavoidable consequence of libuv, for example. Either something about my mental model is off, or something isn't quite right on the plugin side of things.

[BurntSushi]

And note that a work around is very simple here. No flag is needed. Just pass ./ to ripgrep.

[datanoise]

I've just checked and the plugin is working fine with the regular Vim. It must be something related to the way NeoVim implements the communication with the external processes. So I assumed that it is related to libuv, but I'm not 100% sure about it.

Passing ./ to ripgrep doesn't help with the problem.

[BurntSushi]

Passing ./ to ripgrep doesn't help with the problem.

That's quite interesting because that should disable stdin detection. Hmmm.

[datanoise]

Maybe i'm using it incorrectly. Is this a correct way to run it?:

rg -H --no-heading --vimgrep is_socket ./

[BurntSushi]

Yes. That should not try to "detect" whether stdin is readable or not. But maybe my understanding is wrong. I'll check the code again once I'm back on a keyboard.

[kevinhwang91]

diff --git a/plugin/grepper.vim b/plugin/grepper.vim
index 73e4e36..40c455f 100644
--- a/plugin/grepper.vim
+++ b/plugin/grepper.vim
@@ -935,6 +935,7 @@ function! s:run(flags)
           \ 'on_stdout': function('s:on_stdout_nvim'),
           \ 'on_stderr': function('s:on_stdout_nvim'),
           \ 'on_exit':   function('s:on_exit'),
+          \ 'pty': 1
           \ }
     if !a:flags.stop
       let opts.stdout_buffered = 1

should work.
using pty option will close stdin. I'm not instead in a PR for vim-grepper. Free feel to borrow the idea. Because the plugin is not specified to rg, I don't know whether this cause the side effective for other tools.

[blueyed]

Note that this also affects other (Neovim) plugins, which used the workaround to append ".": nvim-telescope/telescope.nvim#908

And note that a work around is very simple here. No flag is needed. Just pass ./ to ripgrep.

Any specific reason to use ./, or is . enough already / the same?

[datanoise]

```diff
diff --git a/plugin/grepper.vim b/plugin/grepper.vim
index 73e4e36..40c455f 100644
--- a/plugin/grepper.vim
+++ b/plugin/grepper.vim
@@ -935,6 +935,7 @@ function! s:run(flags)
           \ 'on_stdout': function('s:on_stdout_nvim'),
           \ 'on_stderr': function('s:on_stdout_nvim'),
           \ 'on_exit':   function('s:on_exit'),
+          \ 'pty': 1
           \ }
     if !a:flags.stop
       let opts.stdout_buffered = 1

should work.
using pty option will close stdin. I'm not instead in a PR for vim-grepper. Free feel to borrow the idea. Because the plugin is not specified to rg, I don't know whether this cause the side effective for other tools.

Thanks. That fixes the issue. It seems to work fine with other tools like ag and grep.

[BurntSushi]

OK, doing a bit of a code walkthrough here, this is the implementation of is_stdin_readable:

ripgrep/crates/cli/src/lib.rs

Lines 183 to 213 in 7ce66f7

	/// Returns true if and only if stdin is believed to be readable.
	///
	/// When stdin is readable, command line programs may choose to behave
	/// differently than when stdin is not readable. For example, `command foo`
	/// might search the current directory for occurrences of `foo` where as
	/// `command foo < some-file` or `cat some-file | command foo` might instead
	/// only search stdin for occurrences of `foo`.
	pub fn is_readable_stdin() -> bool {
	#[cfg(unix)]
	fn imp() -> bool {
	use same_file::Handle;
	use std::os::unix::fs::FileTypeExt;
	let ft = match Handle::stdin().and_then(|h| h.as_file().metadata()) {
	Err(_) => return false,
	Ok(md) => md.file_type(),
	};
	ft.is_file() || ft.is_fifo() || ft.is_socket()
	}
	#[cfg(windows)]
	fn imp() -> bool {
	use winapi_util as winutil;
	winutil::file::typ(winutil::HandleRef::stdin())
	.map(|t| t.is_disk() || t.is_pipe())
	.unwrap_or(false)
	}
	!is_tty_stdin() && imp()
	}

On Unix, this is getting a handle to stdin's file descriptor, stating it and returning true only if its file type is a regular file, a fifo or a socket. Finally, it only returns true if it knows that stdin is not a tty, which is done via isatty. This might actually be why the pty option works: AIUI, it causes isatty(0) to return true and thus is_readable_stdin would return false regardless of the file type detection.

So where is this used? It's used inside of ripgrep when determining which thing to search when it is otherwise not given at least one thing to search as a positional parameter:

ripgrep/crates/core/args.rs

Lines 1325 to 1342 in 7ce66f7

	/// Return the default path that ripgrep should search. This should only
	/// be used when ripgrep is not otherwise given at least one file path
	/// as a positional argument.
	fn path_default(&self) -> PathBuf {
	let file_is_stdin = self
	.values_of_os("file")
	.map_or(false, |mut files| files.any(|f| f == "-"));
	let search_cwd = !cli::is_readable_stdin()
	|| (self.is_present("file") && file_is_stdin)
	|| self.is_present("files")
	|| self.is_present("type-list")
	|| self.is_present("pcre2-version");
	if search_cwd {
	Path::new("./").to_path_buf()
	} else {
	Path::new("-").to_path_buf()
	}
	}

Whether search_cwd is true or not, in this case, I believe, depends completely on what is_readable_stdin (as defined above) returns. Namely, none of --file, --files, --type-list or --pcre2-version are given to rg here. Thus, in this case, ripgrep will only search the CWD if it believes that stdin is not readable. If the plugin runs ripgrep in a way that causes stdin to be open, not a tty and report itself as a socket, then indeed, ripgrep will consider stdin readable and choose to search it instead of the CWD.

The part where I'm getting hung up is that the path_default routine is only called when no paths are given to ripgrep:

ripgrep/crates/core/args.rs

Lines 554 to 559 in 7ce66f7

	let using_default_path = if paths.is_empty() {
	paths.push(self.path_default());
	true
	} else {
	false
	};

So, if you provide ./ (or ., they are indeed the same), then all this business about stdin sniffing is totally skipped. So the fact that ./ didn't work is quite surprising to me, and if there is an easy way to reproduce that outside of vim in a more controlled experiment, I would consider that a bug. My guess though is that there is probably something else going on.

[BurntSushi]

A clarification: folks seem to think that I am holding a line here because I'm insisting on being "technically correct" here. That's not why I'm doing what I'm doing here. The patch that broke neovim plugin integration was fixing another bug. Perhaps a less prominent one, but not insignificant. So the choice here isn't between "being pragmatic" and "being technically correct." The choice here is, "who do we break?"

(As far as I can tell anyway.)

[blueyed]

@BurntSushi
What do you think of having an explicit flag (or env var) to control this?
The problem with the workaround in vim-grepper (Neovim) to append "." (automatically always) is bad, since it does not allow to search sub-directories then only (by specifying "pattern subdir"), since it would get turned into "rg … pattern subdir .".
(not appending "." in that case (of having specified (a) subdir(s)) is not trivial, given there is a single input line only etc (mhinz/vim-grepper#162))

[BurntSushi]

I'm not keen on adding flags for this. Especially since it looks like a temporary problem.

@blueyed Does the pty trick above not work for you? (Or maybe that's only available in vim and not neovim?)

[BurntSushi]

Crazy untested idea: is it possible to connect stdin to /dev/null? Does that work?

[blueyed]

@BurntSushi
I've tried to close stdin in Neovim, but it is likely too late then already (since it can only be done after the process was started; I've created neovim/neovim#15068 to support this).

The pty-trick needs to be extended (mhinz/vim-grepper#244 (comment)), but might be what ends in vim-grepper if there is nothing better, like a fix/explicit flag in ripgrep.

[wsdjeg]

Why this issue is closed? does this bug have been fixed. I still can reproduce it in my plugin. SpaceVim/SpaceVim#4329

neovim version is: v0.5.0 release

[BurntSushi]

The answer to your question is in the comments above. The problem isn't in ripgrep. Neovim is attaching a readable stdin file descriptor to every subprocess executed. There's even a PR against neovim to fix it. Work arounds have been documented above.

[wsdjeg]

hmm. I do not know. But why old old version of rg works well for me. I need to lock my rg version to 0.10.0

[BurntSushi]

It's explained above. See the link to the commit that introduced this change for example.

You don't need to use an old version of ripgrep. Certainly not one that is many years old. Just use rg foo ./ instead of rg foo.

Again, please read the comments above. It should all be explained. If you have specific questions to things said, feel free to ask.

[ddeville]

To close the loop here (and for those still following this issue), neovim/neovim#14812 landed in Neovim and provides a way for stdin to not be piped when calling jobstart. vim-grepper was updated so that it uses that option in mhinz/vim-grepper#250. This should fix the issue where ripgrep doesn't return any results when used from vim-grepper.

Note that the Neovim fix hasn't been pushed in an official release yet (that is 0.5 doesn't have it) and thus it requires using the nightly 0.6 Neovim build.

Thanks for your help investigating this @BurntSushi!

[wsdjeg]

@ddeville thanks, I am using 0.5.0 now.

[bellini666]

For anyone comming here using vim-grepper, I have a suggestion to help you guys use it and also apply the workaround suggested by this comment: #1892 (comment)

I have a custom function that gets called by some keymappings that I ported from this plugin a while ago: https://github.com/vim-scripts/grep.vim . The function is:

function! s:my_run_grep()
    let l:pattern = trim(input('Search for pattern: ', expand('<cword>')))
    if l:pattern == ''
      return
    endif
    let l:pattern = '"' . substitute(l:pattern, '"', '\"', "g") . '"'
    echo "\r"

    let l:dirs = trim(input('Limit for directory: ', './', 'dir'))
    if l:dirs != ''
      let l:dirs = '"' . l:dirs . '"'
    endif
    echo "\r"

    let l:files = trim(input('Limit for files pattern: ', '*'))
    if l:files == '*'
      let l:files = ''
    else
      let l:files = '-g "' . l:files . '"'
    endif
    echo "\r"

    :echo "GrepperRg " . l:pattern . " " . l:dirs . " " . l:files
    :execute "GrepperRg " . l:pattern . " " . l:dirs . " " . l:files
endfunction

nnoremap <silent> <Leader>gr :call <SID>my_run_grep()<CR>

So, when I press <Leader>gr (as in Grep Recursive) I get prompted for the pattern, which is autocompleted by the word in my cursor, the directory that I want to run (by default I set it to ./ so it works on current neovim version, but I can very easily type and autocomplete other directories) and later to limit for an optional filetype (e.g. *.py). Also, note that the pattern can have spaces in it because of the way that I execute the command

It speeds up a lot of things for me. If I want to grep for the word in my in my cursor without limiting the directories or the filetypes I can just <Leader>gr and then press <Enter> 3 times in a row.