microsoft / microsoft/vscode-cpptools

Autoformatting with `modificationsIfAvailable` changes too many lines

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bug Feature: Code Formatting Language Service performance
Dominant language
TypeScript
Stars
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Forks
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Avg merge
14h 46m
Merged PRs (30d)
61

Description

Type: Bug

When auto-formatting on save with these settings:

    "[cpp]": {
        "editor.formatOnType": true,
        "editor.formatOnSave": true,
        "editor.formatOnSaveMode": "modificationsIfAvailable"
    },

my changes and the line after them are formatted. Because of that, every save formats one more line (the extra formatted line from the first save counts as a change for the second save, which formats one more extra line, etc.)

This leads to way too many changes when saving a file multiple times.

Some more details: I'm using clang-format configured for space-indentation while changing a tab-indented file.

Extension version: 1.19.8
VS Code version: Code 1.87.2 (863d2581ecda6849923a2118d93a088b0745d9d6, 2024-03-08T15:20:17.278Z)
OS version: Windows_NT x64 10.0.22631
Modes:

System Info
Item Value
CPUs AMD Ryzen 9 5900X 12-Core Processor (24 x 3700)
GPU Status 2d_canvas: enabled
canvas_oop_rasterization: enabled_on
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: disabled_off
video_decode: enabled
video_encode: enabled
vulkan: disabled_off
webgl: enabled
webgl2: enabled
webgpu: enabled
Load (avg) undefined
Memory (System) 63.93GB (37.62GB free)
Process Argv --crash-reporter-id 0ac330db-34c3-4766-8c92-8e2a96e97825
Screen Reader no
VM 0%
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Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No source file or test is named. Reproduce the issue with clang-format, a tab-indented C++ file, and the shown modificationsIfAvailable settings; then trace the format-on-save path. Done means repeated saves format only the changed lines and no additional line on each save.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, typescript, vscode
Domain
developer-experience, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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