Workaround the drive letter casing issue on windows.

[raldone01]

Fixes: #726.

Lower case drive letters seem to be the cause of the issues.

Not being able to refactor on windows makes clangd borderline unusable.

The workaround can be removed once clangd/clangd#108 is fixed.
In the mean time I think this simple workaround should be quite robust and alleviates the pain.

Why I fixed it here:

Working around the clangd issue in the vscode extension is much easier than attempting to tame the beast that is clangd.
The impact of the workaround is also very small.

Some things I am uncertain about:

I don't know if clangd normalizes paths at all.
If it doesn't:

Maybe a setting should be added to decide between upper and lower case drive letter normalization on windows.
I have never observed lower case ones in compile_commands.json though.
So we should probably wait for complaints 😁 before adding the setting.

Note:

I changed the typescript target because I needed named capture groups.
Maybe it is also time to move on from commonjs to "module": "Node16",.

[JVApen]

Do we know where the lower case letter comes from? I'm a bit worried that this change fixes the symptoms instead of the underlying problem. If that's the case, clangd might know about the same file twice with different casing. I wouldn't be surprised to find out that more issues would popup.

[JVApen]

On our systems, using both Windows with vs code and CMake, it always uses the same casing, which I believe is upper case.

[raldone01]

I don't know the origin but probably cmake? It generates the compile commands after all.

Ideally clangd should normalise every path it receives/reads using some library. Then all these issues should go away. I am sure cpp has some sort of normalise function.

[raldone01]

On our systems, using both Windows with vs code and CMake, it always uses the same casing, which I believe is upper case.

So it works on your system. When the drive letter casing is already uppercase, my code should have no effect.

Did this branch cause issues on your systems?

[artem-kamyshev]

Any progress here or on the main issue? It's unfortunate that we as devs have to apply our own fixes to make the tooling work.

[ccll]

May I ask why this PR is not accepted?

From these historical discussions:

• Case-sensitive path handling is error prone on Win/Mac clangd#108
• Duplicates in response of "textDocument/references" request clangd#2195
• Renaming will fail under certain circumstances #687
• Renaming function failed across files #779

We can see that:

• CMake generates compile_commands.json with upper case "C:"
• vscode sends the file name with lower case "c:" to vscode-clangd
• clangd is confused with the two version and generates duplicated rename operations

So we either:

• let CMake generates lower case "c:"
• or let vscode sends upper case "C:"
• or let clangd deduplicate same file in different case
• or let vscode-clangd transform lower case "c:" to upper case "C:"

Is my understanding correct?

If so, @raldone01 the author of the PR might be right that vscode-clangd is the most easy solution here.

[HighCommander4]

I think the proper solution is this one:

let clangd deduplicate same file in different case

There is work in progress towards it at llvm/llvm-project#136439.