Inconsistent jedi_completion with snippets enabled client (vim-lsp)

[torimus]

Using Vim 9.1 with latest vim-lsp and UltiSnips integration. I do explicitly enable in pylsp.plugins

• jedi_completion.enabled to true
• jedi_completion.include_params to true

When I invoke code completion at symbol, sometimes lsp#complete inserts function including parameters as snippet placeholders

finishing completion inserts selected function with arguments as snippet placeholders:

However in a quite similar case, insertion of function arguments does not happen

results in

Possible bug in jedi_completion plugin? Any other explanation?

[krassowski]

Currently only an initial set of completion items (by default 25) receive snippets:

python-lsp-server/pylsp/plugins/jedi_completion.py

Lines 262 to 264 in 04fa3e5

	if include_params and not is_exception_class(d.name):
	snippet = _snippet(d, resolve_label_or_snippet)
	completion.update(snippet)

And snippets are not resolved in completionItem/resolve:

python-lsp-server/pylsp/plugins/jedi_completion.py

Lines 139 to 156 in 04fa3e5

	@hookimpl
	def pylsp_completion_item_resolve(config, completion_item, document):
	"""Resolve formatted completion for given non-resolved completion"""
	shared_data = document.shared_data["LAST_JEDI_COMPLETIONS"].get(
	completion_item["label"]
	)
	completion_capabilities = config.capabilities.get("textDocument", {}).get(
	"completion", {}
	)
	item_capabilities = completion_capabilities.get("completionItem", {})
	supported_markup_kinds = item_capabilities.get("documentationFormat", ["markdown"])
	preferred_markup_kind = _utils.choose_markup_kind(supported_markup_kinds)
	if shared_data:
	completion, data = shared_data
	return _resolve_completion(completion, data, markup_kind=preferred_markup_kind)
	return completion_item

This might explain it.

[krassowski]

The specification forbids changing insertText in resolution phase unless completionItem#resolveSupport lists it:

By default the request can only delay the computation of the detail and documentation properties. Since 3.16.0 the client can signal that it can resolve more properties lazily. This is done using the completionItem#resolveSupport client capability which lists all properties that can be filled in during a ‘completionItem/resolve’ request. All other properties (usually sortText, filterText, insertText and textEdit) must be provided in the textDocument/completion response and must not be changed during resolve

So it will only work for clients which do that.