VSCode is implement its own solution for glob pattern matching and does not rely on a 3rd party module. The reasons are mostly historic but our glob patterns also behave slightly different compared to others (e.g. **/foo.txt matches on foo.txt, both backslash and slash are supported).
Our glob matching works in 2 stages:
- if it matches a typical pattern (such as
**/*.js), we optimize the matching to avoid a regex use (from here)
- otherwise we try to convert the pattern into a single regex to match (from here)
Specifically for the conversion of ** to a regular expression we have a flaw that results in the issue at hand here, the regex is:
|
// Matches: (Path Sep OR Path Val followed by Path Sep OR Path Sep followed by Path Val) 0-many times |
|
// Group is non capturing because we don't need to capture at all (?:...) |
|
// Overall we use non-greedy matching because it could be that we match too much |
|
return `(?:${PATH_REGEX}|${NO_PATH_REGEX}+${PATH_REGEX}|${PATH_REGEX}${NO_PATH_REGEX}+)*?`; |
Or specifically for **/p* ends up to be:
/^(?:[/\\]|[^/\\]+[/\\]|[/\\][^/\\]+)*?p[^/\\]*?$/
Unfortunately, given a string of /foo/ap, the segment [/\\][^/\\]+ eagerly matches on /a and as such, the overall result is a match, even though that is unexpected.
Help wanted
Opening up for others to contribute, the solution should:
- preserve our tests for globs to succeed (
glob.test.ts)
- enable the now skipped test to succeed (code)
- somewhat preserve our strategy for computing a single regex for matching [1]
[1] however if this is not possible, I am also open for ideas how to solve this differently if the solution is not overly complex.
VSCode is implement its own solution for glob pattern matching and does not rely on a 3rd party module. The reasons are mostly historic but our glob patterns also behave slightly different compared to others (e.g.
**/foo.txtmatches onfoo.txt, both backslash and slash are supported).Our glob matching works in 2 stages:
**/*.js), we optimize the matching to avoid a regex use (from here)Specifically for the conversion of
**to a regular expression we have a flaw that results in the issue at hand here, the regex is:vscode/src/vs/base/common/glob.ts
Lines 57 to 60 in c7fcb30
Or specifically for
**/p*ends up to be:Unfortunately, given a string of
/foo/ap, the segment[/\\][^/\\]+eagerly matches on/aand as such, the overall result is a match, even though that is unexpected.Help wanted
Opening up for others to contribute, the solution should:
glob.test.ts)[1] however if this is not possible, I am also open for ideas how to solve this differently if the solution is not overly complex.