C/C++ Configuration Auto-generator Triggers If Path Separators Are Edited

I refer to PR #1183 which provided the feature of auto-generating c_cpp_configuration.json to the vscode-arduino extension.

The auto-generation of the config file is a welcome one and saves effort in preparing an Arduino workspace. However, editing the config file after its generation can sometimes lead to the auto-generator triggering on (re-)startup, leading to duplicate/redundant string values within the file.

Version Information

OS used: Windows 10 (10.0.19042) VS Code: 1.54.1 (user setup) vscode-arduino: 0.3.5 (master) Relevant for later report on steps taken as well as suggestion: ms-vscode.cpptools: 1.2.2

Configuration File Used

I am including the file as a code block below:

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**",
                "C:\\Users\\jiaju\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.3\\**",
                "C:\\Program Files (x86)\\Arduino\\libraries\\**",
                "C:\\Users\\jiaju\\Documents\\Arduino\\libraries\\**",
                "C:\\Users\\jiaju\\AppData\\Local\\Arduino15\\packages\\arduino\\tools\\**"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE",
                "USBCON"
            ],
            "cStandard": "c11",
            "cppStandard": "c++11",
            "compilerPath": "C:/Program Files (x86)/Arduino/hardware/tools/avr/bin/avr-gcc.exe",
            "intelliSenseMode": "gcc-x64",
            "forcedInclude": [
                "C:\\Users\\jiaju\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.3\\cores\\arduino\\Arduino.h"
            ]
        }
    ],
    "version": 4
}

Steps Taken

Using the find and replace function (Ctrl+H) I replaced all instances of \\ with /. The changed parts of the file would be

        "includePath": [
            "${workspaceFolder}/**",
            "C:/Users/jiaju/AppData/Local/Arduino15/packages/arduino/hardware/avr/1.8.3/**",
            "C:/Program Files (x86)/Arduino/libraries/**",
            "C:/Users/jiaju/Documents/Arduino/libraries/**",
            "C:/Users.jiaju/AppData/Local/Arduino15/packages/arduino/tools/**"
        ],

and

        "forcedInclude": [
            "C:/Users/jiaju/AppData/Local/Arduino15/packages/arduino/hardware/avr/1.8.3/cores/arduino/Arduino.h"
        ]

I saved the configuration file without any renaming.

I closed the VS Code window and opened it again.

I expected to not find any changes to the configuration file, however I found the following in the sections that I changed:

    "includePath": [
        "${workspaceFolder}/**",
        "C:/Users/jiaju/AppData/Local/Arduino15/packages/arduino/hardware/avr/1.8.3/**",
        "C:/Program Files (x86)/Arduino/libraries/**",
        "C:/Users/jiaju/Documents/Arduino/libraries/**",
        "C:/Users.jiaju/AppData/Local/Arduino15/packages/arduino/tools/**",
        "C:\\Users\\jiaju\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.3\\**",
        "C:\\Program Files (x86)\\Arduino\\libraries\\**",
        "C:\\Users\\jiaju\\Documents\\Arduino\\libraries\\**",
        "C:\\Users\\jiaju\\AppData\\Local\\Arduino15\\packages\\arduino\\tools\\**"
    ],

    "forcedInclude": [
        "C:/Users/jiaju/AppData/Local/Arduino15/packages/arduino/hardware/avr/1.8.3/cores/arduino/Arduino.h",
        "C:\\Users\\jiaju\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.3\\cores\\arduino\\Arduino.h"
    ]

I retested steps 1-3 but only changing one string's separators to / at a time, leaving the other relevant strings with \\ separators and deleting the redundant strings, with similar results as above.
I changed the setting "C_cpp: Preferred Path Separator" (C_Cpp.preferredPathSeparator in settings.json) from the default 'Forward Slash' to 'Backslash' thinking that it may be related to the issue. This did not affect the results of subsequent retests, and I reverted this change on my settings.

Impact

This does not appear to have any significant performance impact other than additional startup time for VS Code to write in the auto-generated lines. However, this does impact on code uniformity especially since other string values such as for the compilerPath key are accepted and do not trigger the auto-generator even with the / separator.

Suggestions

To have an extension setting for path separator preference similar to the setting present in ms-vscode.cpptools, allowing the user to choose between the Unix/Mac / or DOS \\ separators, or rely on system/default settings instead.
To have an extension setting for the auto-generator to be bypassed/ignored, or only trigger if there is no c_cpp_configuration.json in the workspace.
When parsing c_cpp_configuration.json on setup, have relevant string values with alternate separator characters be recognised as valid and not trigger the auto-generator as a result.

Thank you for reading this admittedly long issue post and hope that this situation can be improved.

microsoft / vscode-arduino