No method completions after `.` inside Ruby string interpolations (`#{obj.}`)

[bolandross]

Summary

Typing . after an identifier inside a Ruby string interpolation does not show method completions. The same identifier outside the string completes normally.

Reproduction

sentence = gets

# Completions appear here:
sentence.

# Completions do not appear here:
puts "The input consisted of #{sentence.} words."
#                                      ^

Open a .rb file with a language server running (ruby-lsp or Solargraph).
2. Type sentence. outside any string — the completion menu shows methods.
3. Type #{sentence.} inside a double-quoted string — no completion menu.

Manual editor: show completions (ctrl-space) also does not help.

[vitallium]

@bolandross Hi! Can you please attach language server logs when you invoke completion? Usually, this should be handled by a language server. Thanks.

[bolandross]

Thanks — logs below, with RPC messages enabled. I retested both positions separately:

Zed sends textDocument/completion outside the string and shows the menu. Inside #{...} it never sends that request.

A. Outside the string (sentence.) — menu appears

// Send:
{"jsonrpc":"2.0","method":"textDocument/didChange","params":{"textDocument":{"uri":"file:///Users/boland/Downloads/ruby_input_test/main.rb","version":29},"contentChanges":[{"range":{"start":{"line":4,"character":8},"end":{"line":4,"character":8}},"text":"."}]}}
{"jsonrpc":"2.0","id":152,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///Users/boland/Downloads/ruby_input_test/main.rb"},"position":{"line":4,"character":9},"context":{"triggerKind":2,"triggerCharacter":"."}}}

// Receive (took 8.7ms):
{"jsonrpc":"2.0","id":152,"result":{"isIncomplete":false,"items":[
  {"label":"chomp","kind":2,"detail":"(separator = ?) => String","data":{"path":"String#chomp"}},
  {"label":"split"},
  "... many more String methods ..."
]}}

Zed then sent several completionItem/resolve requests (chomp, split, …), so the completion menu was actually shown.

B. Inside interpolation (#{sentence.}) — no menu

Same file, same server, only the cursor is inside the interpolation:

// Send:
{"jsonrpc":"2.0","method":"textDocument/didChange","params":{"textDocument":{"uri":"file:///Users/boland/Downloads/ruby_input_test/main.rb","version":47},"contentChanges":[{"range":{"start":{"line":4,"character":40},"end":{"line":4,"character":40}},"text":"."}]}}
{"jsonrpc":"2.0","id":228,"method":"textDocument/documentHighlight","params":{"textDocument":{"uri":"file:///Users/boland/Downloads/ruby_input_test/main.rb"},"position":{"line":4,"character":41}}}

// Receive (took 1.6ms):
{"jsonrpc":"2.0","id":228,"result":[]}

// Receive:
{"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"uri":"file:///Users/boland/Downloads/ruby_input_test/main.rb","diagnostics":[{"range":{"start":{"line":4,"character":41},"end":{"line":4,"character":42}},"severity":1,"source":"rubocop","code":"Lint/Syntax","message":" unexpected '}'; expecting a message to send to the receiver\n(Using Ruby 4.0 parser; configure using `TargetRubyVersion` parameter, under `AllCops`)"}]}}

There is no textDocument/completion request after typing . inside #{sentence.}. The language server never gets a chance to return items.

So this is not the language server dropping completions — Zed does not ask for them in that scope.

That points at the Ruby string override treating the interpolation as a string:

; languages/ruby/overrides.scm
(string) @string

[overrides.string]
completion_query_characters = ["-", "."]

Because the whole (string) node includes (interpolation), typing . after sentence is handled as a string-scope query character (for Tailwind-style class names) instead of an LSP trigger character.

Same class of bug as zed-industries/zed#33703 / #33997 (JS/TS template interpolations should not be @string).

[vitallium]

Awesome, thanks for this detailed info! Should be fixed with #319