feat: add fs/resolve-parent-paths-by

[gururaj1512]

Resolves #2567.

Description

What is the purpose of this pull request?
Adds JS implementation for @stdlib/fs/resolve-parent-paths-by/

This pull request:

• resolves [RFC]: add @stdlib/fs/resolve-parent-paths-by #2567

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves [RFC]: add @stdlib/fs/resolve-parent-paths-by #2567

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

---

@stdlib-js/reviewers

[gururaj1512]

hey @kgryte, can you explain this linting error in README file at line 3.

[Snehil-Shah]

@gururaj1512 is this when you try to commit?

[gururaj1512]

@Snehil-Shah that error occurs when commiting and also while running eslint

[Snehil-Shah]

@gururaj1512 Weird. I can't seem to reproduce the error. Did you follow the setup guide properly? (make install, make init). Maybe try clean installing and setting up again (after make clean).
Also, can you show the full error and what exactly are/were you trying to commit?

[gururaj1512]

@gururaj1512 Weird. I can't seem to reproduce the error. Did you follow the setup guide properly? (make install, make init). Maybe try clean installing and setting up again (after make clean). Also, can you show the full error and what exactly are/were you trying to commit?

Yaa, I have tried make clean & make install

This error occurs while running command npx eslint path/to/directory/

[Snehil-Shah]

@gururaj1512 Weird. I can't seem to reproduce the error. Did you follow the setup guide properly? (make install, make init). Maybe try clean installing and setting up again (after make clean). Also, can you show the full error and what exactly are/were you trying to commit?

Yaa, I have tried make clean & make install This error occurs while running command npx eslint path/to/directory/

Ok, was able to reproduce it. Seems to me, it's something specific to npx as I am able to commit the file without any errors. And in any case, you don't need to run npx eslint manually, the linter is automatically triggered before every commit via git hooks (assuming your environment is set up as expected). If you still wish to manually trigger the linter, you can use the make recipes (like make lint) listed here.

[Snehil-Shah]

LGTM otherwise!

[Snehil-Shah]

Also, was the issue with your dev environment resolved @gururaj1512?

[gururaj1512]

Also, was the issue with your dev environment resolved @gururaj1512?

@Snehil-Shah, the issue with my dev environment has been resolved. Thank you for checking in!

[Snehil-Shah]

LGTM. On to @kgryte.

[kgryte]

This logic seems off. test may be an asynchronous function. In which case, the onTest callback will be called after hitting FLG += 1. If done multiple times, that could mean that L203-221 could be exercised before any onTest call is complete. This race condition needs to be addressed.

[gururaj1512]

@kgryte, I wanted to clarify whether using async/await to wait for the test function to complete would be an appropriate solution here.

[kgryte]

No, no using async/await. This implementation should be entirely callback-based

[gururaj1512]

function some( paths, dir, test, done ) {
	var child;
	var spath;
	var FLG;
	var out;

	FLG = 0; // initialize flag to track if we are done traversing a directory level
	out = [];

	// Start at a base directory and continue moving up through each parent directory...
	return next( dir );

	/**
	* Resolves paths within a directory.
	*
	* @private
	* @param {string} dir - directory to search
	*/
	function next( dir ) {
		var i;
		for ( i = 0; i < paths.length; i++ ) {
			spath = resolve( dir, paths[ i ] );
			exists( spath, getCallback( spath ) );
		}
	}

	/**
	 * Returns a callback to be invoked upon checking for path existence.
	*
	* @private
	* @param {string} spath - resolved path
	* @returns {Callback} callback
	*/
	function getCallback( spath ) {
		return onExists;

		/**
		* Callback invoked after testing a resolved path.
		*
		* @private
		* @param {(Error|null)} error - error object
		* @param {boolean} bool - boolean indicating if a path exists
		* @returns {void}
		*/
		function onTest( error, bool ) {
			if ( error ) {
				return done( error );
			}
			if ( bool ) {
				out.push( spath );
			}
			// Increment flag after `test` completes:
			FLG += 1;
			if ( FLG === paths.length ) {
				// Check if we have resolved any paths...
				if ( out.length > 0 ) {
					return done( null, out );
				}
				// Resolve a parent directory:
				child = dir;
				dir = resolve( dir, '..' );

				// Reset flag:
				FLG = 0;

				// If we have already reached root, we cannot resolve any higher directories...
				if ( child === dir ) {
					return done( null, out );
				}
				// Resolve paths at next directory level:
				return next( dir );
			}
		}

		/**
		* Callback invoked after checking for path existence.
		*
		* @private
		* @param {(Error|null)} error - error object
		* @param {boolean} bool - boolean indicating if a path exists
		* @returns {void}
		*/
		function onExists( error, bool ) { // eslint-disable-line node/handle-callback-err
			if ( bool ) {
				// Pass the path to the `test` function and use `onTest` as the callback:
				test( spath, onTest );
			} else {
				// Increment flag if the path does not exist:
				FLG += 1;
				if ( FLG === paths.length ) {
					// Check if we have resolved any paths...
					if ( out.length > 0 ) {
						return done( null, out );
					}
					// Resolve a parent directory:
					child = dir;
					dir = resolve( dir, '..' );

					// Reset flag:
					FLG = 0;

					// If we have already reached root, we cannot resolve any higher directories...
					if ( child === dir ) {
						return done( null, out );
					}
					// Resolve paths at next directory level:
					return next( dir );
				}
			}
		}
	}
}

Does this work out

[gururaj1512]

@kgryte, Am I doing it right in above mentioned programme, It passes all test cases & would pass the race conditions during async processing

[kgryte]

Same problem here.

[kgryte]

This PR needs to address the race conditions during async processing before we can merge.