include msvc rust-specific information formatters

[rbtcollins]

There is a discussion that notes in VSCode that people are getting an error/warning about debug information formatters with codelldb on Windows.

Developers are steered to CodeLLDB by the vscode Rust ecosystem; the codelldb note that is referred to from that bug says that 'as it is assumed that users will primarily use WinDbg or Microsoft Visual Studio's debugger for this target' - I think that this assumption is wrong.

It would be great to include the rust debug information formatters for codelldb with the msvc toolchain.

[Walnut356]

Rust formatters were a part of codelldb until 1.11, at which point they were deliberately replaced with the formatters distributed by rust itself to decrease the maintenance burden on codelldb.

Rust did not include LLDB and GDB formatters with *-msvc distributions for some reason. As of this pr, that is no longer the case. While the formatters will exist in *-msvc distributions, they still don't function very well. That is actively being worked on by myself and a few others. In the meantime, they're just python scripts so they can altered/copied/replaced to improve their functionality locally.

[tanveerbadar]

Rust formatters were a part of codelldb until 1.11, at which point they were deliberately replaced with the formatters distributed by rust itself to decrease the maintenance burden on codelldb.

Rust did not include LLDB and GDB formatters with *-msvc distributions for some reason. As of this pr, that is no longer the case. While the formatters will exist in *-msvc distributions, they still don't function very well. That is actively being worked on by myself and a few others. In the meantime, they're just python scripts so they can altered/copied/replaced to improve their functionality locally.

Looking at your PRs, it seems the fixes won't be available till 1.87 comes out? Needless to say, the currently horribly broken enum displays make working with my enum heavy codebase a total pain and I can't wait for these fixes.

[Walnut356]

Correct, as of now all of the patches for baseline functionality have landed and once 1.87 is released, everything should work out of the box.

If you're willing to use nightly, you can take advantage of the changes right away.

The compiler patch to fix enum discriminants should be included in stable 1.86. iirc the patch that lands in 1.87 is purely changes to the python scripts. As such, when 1.86 comes out you can grab the lldb_commands, lldb_providers.py, lldb_lookup.py and rust_types.py from the current main branch of rust and replace the files in your locally installed *-msvc toolchain.

Using those files on 1.85 will still be an improvement for things like Vec, Hashmap, and tuples, but sum-type enums wont be able to determine which variant to display.

[prg318]

How can codelldb users use the rust language-provided LLDB data formatters with codelldb? When I directly launch rust-lldb (which adds the rust data formatter script to a lldb interpreter), collections such as HashMaps are properly shown when printed, but I can't seem to find a way to get codelldb to use these formatting scripts.
(edit) ANSWER: Check out codelldb/lang_support/rust.py for specifics on how this works. Keep in mind that this script will only get called if rust is specified in the sourceLanguages field of the debug configuration

edit: This does actually work once you specify rust as a source language in your debug configuration. At first I wasn't sure if this was possible with neovim's dap-debug plugin, but it is if you add sourceLanguages = {'rust'}, to dap.configurations.rust. I'll keep my comment around with these edits in hopes that it might help someone else in the same situation

I see this relevant section of the rust support section of the manual:
"CodeLLDB will attempt to locate and load LLDB data formatters provided by the Rust toolchain. By default, the configured toolchain of your workspace root will be used"
But I have my rust toolchain default set to stable-x86_64-pc-windows-gnu and codelldb does not seem to include the rust formatters (even though rust-lldb works with that toolchain)
(edit) ANSWER: I didn't have sourceLangauges specified in my DAP configuration