Autodetect indentSize cannot detect tabs for a TSV file

[kriswuollett]

Issue Type: Bug

A file containing tabs instead of spaces, especially one with a .tsv file extension should automatically be detected to be indented using tabs when editor.detectIndentation is set to true.

Steps to Reproduce:

• Include in Settings: "editor.detectIndentation": true
• Create a file named something like packages.tsv
• Press the Spaces: 4 button at the bottom and select Indent Using Tabs, tab size 4
• Add content to the file and save like the following:

_	10	nodejs	16.7.0
_	10	awscli	2.2.32
_	10	terraform	1.0.5
_	10	golang	1.17.1
apt	10	vim	_

• Close the file and reopen it, the mode used is Spaces: 4 when it should have been detected as Tab Size: 4
• Detect Indentation from Content also does not change the mode to tabs (I assume this is the same issue)

VS Code version: Code 1.60.0 (e7d7e9a, 2021-09-01T10:54:53.442Z)
OS version: Darwin x64 20.6.0
Restricted Mode: No
Remote OS version: Linux x64 5.10.47-linuxkit

System Info

Item	Value
CPUs	Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz (16 x 2300)
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	64.00GB (0.03GB free)
Process Argv	--crash-reporter-id 8067519b-e432-4f58-bfd4-020219e81bca
Screen Reader	no
VM	0%

Item	Value
Remote	Dev Container: kriswuollett
OS	Linux x64 5.10.47-linuxkit
CPUs	Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz (8 x 2300)
Memory (System)	15.64GB (1.58GB free)
VM	0%

Extensions (14)

Extension	Author (truncated)	Version
postcss	css	1.0.9
mustache	daw	1.1.1
flatbuffers	gab	0.1.0
jq-syntax-highlighting	jq-	0.0.2
python	ms-	2021.9.1218897484
vscode-pylance	ms-	2021.9.1
jupyter-keymap	ms-	1.0.0
remote-containers	ms-	0.194.0
remote-ssh	ms-	0.65.7
remote-ssh-edit	ms-	0.65.7
vscode-pbtxt	the	0.0.3
aws-toolkit-vscode	ama	1.29.0
terraform	has	2.14.0
vscode-docker	ms-	1.16.1

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python383:30185418
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vspor879:30202332
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vstes627:30244334
pythonvspyt639:30300192
pythontb:30283811
pythonvspyt551:30345470
pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
vscoreces:30358480
pythondataviewer:30285071
pythonvsuse255:30340121
vscod805:30301674
pythonvspyt200:30340761
vscextlang:30333561
binariesv615:30325510
vsccppwt:30364497
pythonvssor306:30344512
bridge0708:30335490
pygetstartedt2:30360495
bridge0723:30353136
pythonrunftest32:30365366
pythonf5test824:30361777
javagetstartedt:30364666
pythonvspyt187cf:30365362
pydsgsc2:30361791
vscus224:30358039
vssid140:30363603
vssur157:30365996

[kriswuollett]

Currently the workaround is run the Indent Using Tabs - Tabs Size: 4 every single time I open a relevant file to avoid accidentally inserting spaces into it. It would be more optimal if the indentation autodetect took care of this for me.

[alexdima]

The indentation detection is based exclusively on leading whitespace. A workaround would be to use language specific settings. Assuming you have installed an extension that adds CSV support and defines the csv language, you can use:

"[csv]": {
  "editor.detectIndentation": false,
  "editor.insertSpaces": false
}