Document with space at end of a comment generates format edit with overlapping ranges

[dalek09]

Type: Bug

Install new instance of VS Code.

Create a .ts (typescript) file with the following:-

function noReformat(noReformat:string){
console.log(noReformat)
}

	// function fun(myVariable) {
	// 	let variable = myVariable;	// this line with whitespace at the end stops format document from working 
	// }

Open the file and press Shift-Alt-F to reformat.

Expected result: document reformats i.e. inserts some spaces.
Actual result: no reformatting occurs.

Then, remove the space at the end of line 6 (i.e. after the word working) and press Shift-Alt-F to reformat; result reformatting now works correctly.

VS Code version: Code 1.81.1 (6c3e3dba23e8fadc360aed75ce363ba185c49794, 2023-08-09T22:22:42.175Z)
OS version: Windows_NT x64 10.0.19045
Modes:

System Info

Item	Value
CPUs	Intel(R) Pentium(R) CPU G2020 @ 2.90GHz (2 x 2900)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: disabled_off opengl: enabled_on rasterization: unavailable_off raw_draw: disabled_off_ok video_decode: enabled video_encode: unavailable_off vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled
Load (avg)	undefined
Memory (System)	5.70GB (0.53GB free)
Process Argv	C:\Users\Derek\Desktop\Test.ts --crash-reporter-id 0213dfee-3f65-4d85-841a-4c77b6df0f67
Screen Reader	no
VM	0%

Extensions: none

A/B Experiments

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vsreu685:30147344
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pythongtdpath:30769146
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pythonnosmt12:30797651
pythonidxpt:30805730
pythonnoceb:30805159
synctok:30821570
dsvsc013:30795093
dsvsc014:30804076
diffeditorv2:30821572
dsvsc015:30823817

[mjbvz]

Seems to work for me

Does this reproduce in the latest VS Code insiders build with all extensions disabled?

[dalek09]

I just uninstalled VS Code and installed the x64 Insider build System Installer. No extensions. Here's the test file (zipped):-
Test.zip
Open it and press Shift-Alt-F: nothing happens. Remove the trailing space from line 7 (after the word "working") and press Shift-Alt-F: document re-formats (spaces around function parameters etc).

Version: 1.82.0-insider (system setup)
Commit: 16e9205452dd417e32f164325b589b94892846b4
Date: 2023-09-06T08:16:52.204Z
Electron: 25.8.0
ElectronBuildId: 23503258
Chromium: 114.0.5735.289
Node.js: 18.15.0
V8: 11.4.183.29-electron.0
OS: Windows_NT x64 10.0.19045

[mjbvz]

Thanks. Yes I can repo now using the file instead of copy and pasting from GitHub

[mjbvz]

The bug appears to be that format generates overlapping edits in this case:

    {
        "seq": 0,
        "type": "response",
        "command": "format",
        "request_seq": 60,
        "success": true,
        "body": [
            {
                "start": {
                    "line": 1,
                    "offset": 32
                },
                "end": {
                    "line": 1,
                    "offset": 32
                },
                "newText": " "
            },
            {
                "start": {
                    "line": 1,
                    "offset": 39
                },
                "end": {
                    "line": 1,
                    "offset": 39
                },
                "newText": " "
            },
            {
                "start": {
                    "line": 3,
                    "offset": 1
                },
                "end": {
                    "line": 3,
                    "offset": 2
                },
                "newText": ""
            },
            {
                "start": {
                    "line": 4,
                    "offset": 1
                },
                "end": {
                    "line": 4,
                    "offset": 2
                },
                "newText": ""
            },
            {
                "start": {
                    "line": 5,
                    "offset": 1
                },
                "end": {
                    "line": 5,
                    "offset": 3
                },
                "newText": ""
            },
            {
                "start": {
                    "line": 6,
                    "offset": 1
                },
                "end": {
                    "line": 6,
                    "offset": 3
                },
                "newText": ""
            },
            {
                "start": {
                    "line": 7,
                    "offset": 1
                },
                "end": {
                    "line": 7,
                    "offset": 3
                },
                "newText": ""
            },
            {
                "start": {
                    "line": 6,
                    "offset": 108
                },
                "end": {
                    "line": 6,
                    "offset": 109
                },
                "newText": ""
            },
            {
                "start": {
                    "line": 6,
                    "offset": 108
                },
                "end": {
                    "line": 6,
                    "offset": 109
                },
                "newText": ""
            }
        ]
    }

Notice how the last two edits are identical

[dalek09]

Hello Matt,
I've no idea why you could not reproduce this by the copying the text into a new file; are you using Linux? Is it a line end thing? Anyway I'm glad you're able to reproduce the issue.

I'm not so sure about the re-name; it makes it sound like this is a purely academic exercise to create a bug and therefore not worth much attention. In fact, the sample file was a condensed version of the problem file I was working with and it took me a little while to figure out why it wouldn't re-format.

Anyway, do you think that this will be investigated and fixed anytime soon?