add preference page to format on save (only full file)

[fabrizioiannetti]

rust-analyzer currently does not support range formatting as reported in the capabilites:

"capabilities":{
...
"documentFormattingProvider":true,
"documentRangeFormattingProvider":false,
...

leave the (disabled) preference, to be activated when rust-analyzer supports it.

Copied and modified from eclipse CDT LSP.

[mickaelistria]

Would adding support for documentRangeFormattingProvider in rust-analyzer automatically enable format on save in Corrosion automatically? If so, do you think you'd be capable of fixing that upstream, in rust-analyzer directly, so all IDEs would benefit from it?

[fabrizioiannetti]

Sorry for the late answer, I looked a bit into lsp4e and cdt-lsp and indeed lsp4e looks at the server capabilities and adapts the request accordingly (e.g. the range format might actually do a full-file format).

CDT seems to have the same approach as you suggested: implement both and let lsp4e/the language server take care of adapting the request.

I will enable both options so that once rust-analyzer supports range formatting it will be supported automatically.
Implementing it in rust-analyzer may be beyond what my time/knowledge allows :-), seems to be in the work though:

rust-analyzer.rustfmt.rangeFormatting.enable

Default: false

Enables the use of rustfmt's unstable range formatting command for the textDocument/rangeFormatting request. The rustfmt option is unstable and only available on a nightly build.

I'll give a try to the nightly build.

[fabrizioiannetti]

I tried with the rust nightly toolchain and using an LS settings with (from the rust analyzer docs):

{
  "rustfmt": {
	"rangeFormatting": {
	  "enable": true
	}
  }
}

I get range formatting on save (it also requires this fix on lsp4e: eclipse-lsp4e/lsp4e#1294)

I have also updated the changelog.md, but the jenkins run fails because apparently gdb is missing from the test image, not sure how to address this.