Originally the fuzzy matcher required a match in the final candidate
segment. For example, to match the candidate "foo.bar", the input had
to have at least one character that matched "bar". I previously
removed this requirement as it is too restrictive for deep completions
to be useful.
However, there was still some lingering final-segment favoritism in
the matching algorithm. In particular, there were penalties for not
matching the final segment's first character and for not matching the
final segment's word initial characters. However, these penalties only
made sense when we also required a final segment match. Consider this
example:
User input: "U"
Candidate "ErrUnexpectedEOF" - with only a single segment, we got big
penalties for not matching the leading "E" (since it is the final
segment).
Candidate "ErrUnexpectedEOF.Error" - "ErrUnexpectedEOF" is no longer
the final segment, so we didn't get penalties. And we didn't get
penalties for the final segment "Error" because we finished matching
after the first "U". As a result, this candidate slips through with a
higher score.
Fix by simplifying the skip penalty. Now we only penalize for skipping
the first character of the first or final segment (and the penalty is
lower). For deep completions, the first and final segment are both
"important" segments, so I think it makes sense to focus on both of
them. We don't want to penalize all segment starts because that makes
it harder to match deeper candidates where you often "ignore"
intermediate segments.
I had to adjust a few scores in the tests, but I don't think the
impact will be too big other than fixing the bug.
Fixesgolang/go#35062.
Change-Id: Id17a5c80bf0f80ce252fe990ccfbd51c1bac1c72
Reviewed-on: https://go-review.googlesource.com/c/tools/+/202638
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Remove the input type option. Now everything behaves as "symbol".
We don't use the "text" or "filename" input types, and I don't foresee
us using them. Removing them simplifies the code a bit, but simplifies
the tests a lot. It was tedious to make changes to the matcher logic
because you had to fret over test failure details that didn't actually
matter because we didn't use that functionality.
Change-Id: I651debde9e63ee283d7bc3ad718d22f4b9a127c0
Reviewed-on: https://go-review.googlesource.com/c/tools/+/202637
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Make use of the existing fuzzy matcher to perform server side fuzzy
completion matching. Previously the server did exact prefix matching
for completion candidates and left fancy filtering to the
client. Having the server do fuzzy matching has two main benefits:
- Deep completions now update as you type. The completion candidates
returned to the client are marked "incomplete", causing the client
to refresh the candidates after every keystroke. This lets the
server pick the most relevant set of deep completion candidates.
- All editors get fuzzy matching for free. VSCode has fuzzy matching
out of the box, but some editors either don't provide it, or it can
be difficult to set up.
I modified the fuzzy matcher to allow matches where the input doesn't
match the final segment of the candidate. For example, previously "ab"
would not match "abc.def" because the "b" in "ab" did not match the
final segment "def". I can see how this is useful when the text
matching happens in a vacuum and candidate's final segment is the most
specific part. But, in our case, we have various other methods to
order candidates, so we don't want to exclude them just because the
final segment doesn't match. For example, if we know our candidate
needs to be type "context.Context" and "foo.ctx" is of the right type,
we want to suggest "foo.ctx" as soon as the user starts inputting
"foo", even though "foo" doesn't match "ctx" at all.
Note that fuzzy matching is behind the "useDeepCompletions" config
flag for the time being.
Change-Id: Ic7674f0cf885af770c30daef472f2e3c5ac4db78
Reviewed-on: https://go-review.googlesource.com/c/tools/+/190099
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
