Regex not supporting balance groups or subroutines

[Ma-XX-oN]

Issue Type: Bug

1. Edit a file or open a new file.
2. Go to find (Ctrl+F).
3. Select regex in search (Alt+R).
4. Type in either of the following:

  (?<A>abc)(?<-A>)  # balance group: invalid capture group name
  (abc)(?0)         # numbered subroutine call: invalid group
  (abc)(?R)         # resume match from begining: invalid group
  (?<A>abc)\g<A>    # named subroutine call: invalid escape
  (?<A>abc)(?&A)    # named subroutine call: invalid group

I've marked it as a bug because most newer regex engines have a subroutine or balanced group syntax.

VS Code version: Code 1.62.0 (b3318bc, 2021-11-03T15:23:01.379Z)
OS version: Windows_NT x64 10.0.19043
Restricted Mode: No

System Info

Item	Value
CPUs	AMD Ryzen 7 5700U with Radeon Graphics (16 x 1797)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	7.38GB (1.64GB free)
Process Argv	--crash-reporter-id ff847a9c-5b94-44a0-b759-b62cfb7fa79c
Screen Reader	yes
VM	0%

Extensions (16)

Extension	Author (truncated)	Version
doxdocgen	csc	1.3.2
vscode-pull-request-github	Git	0.32.0
better-cpp-syntax	jef	1.15.10
cortex-debug	mar	0.4.7
remote-containers	ms-	0.205.1
remote-ssh	ms-	0.66.0
remote-ssh-edit	ms-	0.66.0
remote-wsl	ms-	0.58.5
cmake-tools	ms-	1.9.1
cpptools	ms-	1.7.1
cpptools-extension-pack	ms-	1.0.0
vsliveshare	ms-	1.0.5090
vsliveshare-audio	ms-	0.1.91
comment-wrap	nex	0.0.2
code-spell-checker	str	2.0.12
cmake	twx	0.0.17

(1 theme extensions excluded)

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[IllusionMH]

Not a bug. Editor data lives in JS therefore JS regexp engine used for Find, so you rely on features that are supported for JS regexps (by V8) and should use JS syntax. See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Cheatsheet

I guess "numbered subroutine call" and "named subroutine call" should translate to "capturing group" and "named capturing group" and work as expected when you use proper syntax.

I don't think that JS has "balancing groups" or "resume match from begining".

[Ma-XX-oN]

Oh, that's too bad. Looks like the libraries out there aren't capable either. I guess this should be closed then?

[IllusionMH]

I guess that this one can be closed as it works as supposed for current implementation, however I'm not a team member so you can wait for official resolution.

If these features are supported by PRCE2 compliant engine, you can try to use Find in Files which utilizes ripgrep (make sure you close editors as JS RegExp engine is used for open editors even during Find in Files).

I think there might be requests or investigations to use different RE engine for open editors that you can upvote, however I haven't found anything open quickly.

[Ma-XX-oN]

Ok. Waiting for an official response.

[rebornix]

@IllusionMH thanks for your help, you are correct. We don't support this now since we are using JS engine.