feat(autocomplete): match completions against their filterText

[boogie]

Problem

FilteredList matches every completion against the text it displays — its caption, or the value or snippet when there is no caption. A completion whose caption differs from what the user types to reach it is therefore filtered out entirely.

That is the normal shape of a language server completion. The protocol has a field for exactly this, CompletionItem.filterText, because the label and the text being matched are not the same thing:

If the text edit is a replace edit then the range denotes the word used for filtering. If the replace changes the text it most likely makes sense to specify a filter text to be used.

A concrete case: a server offers iframe as the label while the user has typed <ifra. Ace drops the completion, because iframe does not contain <.

The existing escape hatch, skipFilter, is all or nothing — it bypasses scoring and match highlighting along with the filtering, so the completion can no longer be ranked or narrowed at all.

This has forced workarounds downstream. In mkslanc/ace-linters#196 the conclusion was that a proper fix requires changing Ace itself:

this code is put there only as work-around for ace completer's FilteredList (…) So the patch should include re-writing some ace's prototypes.

Change

Completions accept an optional filterText. When present, that is what the completion is matched and scored against, in place of the text it displays.

Compatibility:

• Completions without the property are matched exactly as before — the expression collapses to the previous one.
• An empty string is ignored rather than meaning "match nothing".
• Completions carrying no displayable text at all are still dropped up front, as before.
• It takes precedence over the ignoreCaption option, being set per completion rather than per provider.

The popup's highlight rendering needs no change. $tokenizeRow derives highlight offsets from the caption on its own and skips any part it cannot locate there, so a completion reached through text that does not occur in its caption renders without a highlight rather than breaking. That limitation is documented on the property.

types/ace-modules.d.ts is regenerated for the new property.

Tests

• test: completions are matched against filterText when it is provided — with < part of the identifier, typing <ifra keeps the completion declaring filterText: "<iframe" and drops the one relying on its caption, and inserting it replaces the typed text. Without the change the popup does not open at all.
• test: should filter using filterText even if ignoreCaption true — pins the precedence, alongside the existing ignoreCaption tests.

Open kitchen-sink @ 502966a74c7767caca99eddd292d17aba092ba89