internal/lsp: provide option for case sensitive completion

In CL 192137 deep fuzzy matching was enabled by default. We also have
options independent options "deepCompletion" and "fuzzyMatching" to
control this. When fuzzy matching is disabled, case insensitive prefix
matching is used.

Provide an option, "caseSensitiveCompletion", which allows for case
sensitive prefix matching when fuzzy matching is disabled.

Change-Id: I17c8fa310b2ef79e36cc2f7303e98870690b5903
Reviewed-on: https://go-review.googlesource.com/c/tools/+/194757
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/cmd/test/cmdtest.go

@@ -53,6 +53,10 @@ func (r *runner) FuzzyCompletions(t *testing.T, data tests.FuzzyCompletions, ite
 	//TODO: add command line completions tests when it works
 }
 
+func (r *runner) CaseSensitiveCompletions(t *testing.T, data tests.CaseSensitiveCompletions, items tests.CompletionItems) {
+	//TODO: add command line completions tests when it works
+}
+
 func (r *runner) RankCompletions(t *testing.T, data tests.RankCompletions, items tests.CompletionItems) {
 	//TODO: add command line completions tests when it works
 }

internal/lsp/completion_test.go

@@ -98,6 +98,21 @@ func (r *runner) FuzzyCompletions(t *testing.T, data tests.FuzzyCompletions, ite
 	}
 }
 
+func (r *runner) CaseSensitiveCompletions(t *testing.T, data tests.CaseSensitiveCompletions, items tests.CompletionItems) {
+	for src, test := range data {
+		got := r.callCompletion(t, src, source.CompletionOptions{
+			CaseSensitive: true,
+		})
+		if !strings.Contains(string(src.URI()), "builtins") {
+			got = tests.FilterBuiltins(got)
+		}
+		want := expected(t, test, items)
+		if msg := tests.DiffCompletionItems(want, got); msg != "" {
+			t.Errorf("%s: %s", src, msg)
+		}
+	}
+}
+
 func (r *runner) RankCompletions(t *testing.T, data tests.RankCompletions, items tests.CompletionItems) {
 	for src, test := range data {
 		got := r.callCompletion(t, src, source.CompletionOptions{

internal/lsp/source/completion.go

@@ -104,11 +104,21 @@ type matcher interface {
 	Score(candidateLabel string) (score float32)
 }
 
-// prefixMatcher implements case insensitive prefix matching.
+// prefixMatcher implements case sensitive prefix matching.
 type prefixMatcher string
 
 func (pm prefixMatcher) Score(candidateLabel string) float32 {
-	if strings.HasPrefix(strings.ToLower(candidateLabel), string(pm)) {
+	if strings.HasPrefix(candidateLabel, string(pm)) {
+		return 1
+	}
+	return -1
+}
+
+// insensitivePrefixMatcher implements case insensitive prefix matching.
+type insensitivePrefixMatcher string
+
+func (ipm insensitivePrefixMatcher) Score(candidateLabel string) float32 {
+	if strings.HasPrefix(strings.ToLower(candidateLabel), string(ipm)) {
 		return 1
 	}
 	return -1
@@ -233,8 +243,10 @@ func (c *completer) setSurrounding(ident *ast.Ident) {
 
 	if c.opts.FuzzyMatching {
 		c.matcher = fuzzy.NewMatcher(c.surrounding.Prefix(), fuzzy.Symbol)
+	} else if c.opts.CaseSensitive {
+		c.matcher = prefixMatcher(c.surrounding.Prefix())
 	} else {
-		c.matcher = prefixMatcher(strings.ToLower(c.surrounding.Prefix()))
+		c.matcher = insensitivePrefixMatcher(strings.ToLower(c.surrounding.Prefix()))
 	}
 }
 

internal/lsp/source/options.go

@@ -76,6 +76,7 @@ type Options struct {
 type CompletionOptions struct {
 	Deep              bool
 	FuzzyMatching     bool
+	CaseSensitive     bool
 	Unimported        bool
 	Documentation     bool
 	FullDocumentation bool
@@ -200,6 +201,8 @@ func (o *Options) set(name string, value interface{}) OptionResult {
 		result.setBool(&o.Completion.Deep)
 	case "fuzzyMatching":
 		result.setBool(&o.Completion.FuzzyMatching)
+	case "caseSensitiveCompletion":
+		result.setBool(&o.Completion.CaseSensitive)
 	case "completeUnimported":
 		result.setBool(&o.Completion.Unimported)
 

internal/lsp/source/source_test.go

@@ -210,6 +210,24 @@ func (r *runner) FuzzyCompletions(t *testing.T, data tests.FuzzyCompletions, ite
 	}
 }
 
+func (r *runner) CaseSensitiveCompletions(t *testing.T, data tests.CaseSensitiveCompletions, items tests.CompletionItems) {
+	for src, test := range data {
+		var want []protocol.CompletionItem
+		for _, pos := range test.CompletionItems {
+			want = append(want, tests.ToProtocolCompletionItem(*items[pos]))
+		}
+		_, list := r.callCompletion(t, src, source.CompletionOptions{
+			CaseSensitive: true,
+		})
+		if !strings.Contains(string(src.URI()), "builtins") {
+			list = tests.FilterBuiltins(list)
+		}
+		if diff := tests.DiffCompletionItems(want, list); diff != "" {
+			t.Errorf("%s: %s", src, diff)
+		}
+	}
+}
+
 func (r *runner) RankCompletions(t *testing.T, data tests.RankCompletions, items tests.CompletionItems) {
 	for src, test := range data {
 		var want []protocol.CompletionItem

internal/lsp/testdata/casesensitive/casesensitive.go

@@ -0,0 +1,16 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package casesensitive
+
+func _() {
+	var lower int //@item(lower, "lower", "int", "var")
+	var Upper int //@item(upper, "Upper", "int", "var")
+
+	l //@casesensitive(" //", lower)
+	U //@casesensitive(" //", upper)
+
+	L //@casesensitive(" //")
+	u //@casesensitive(" //")
+}

internal/lsp/tests/tests.go

@@ -34,6 +34,7 @@ const (
 	ExpectedUnimportedCompletionsCount    = 1
 	ExpectedDeepCompletionsCount          = 5
 	ExpectedFuzzyCompletionsCount         = 6
+	ExpectedCaseSensitiveCompletionsCount = 4
 	ExpectedRankedCompletionsCount        = 1
 	ExpectedDiagnosticsCount              = 21
 	ExpectedFormatCount                   = 6
@@ -67,6 +68,7 @@ type CompletionSnippets map[span.Span]CompletionSnippet
 type UnimportedCompletions map[span.Span]Completion
 type DeepCompletions map[span.Span]Completion
 type FuzzyCompletions map[span.Span]Completion
+type CaseSensitiveCompletions map[span.Span]Completion
 type RankCompletions map[span.Span]Completion
 type FoldingRanges []span.Span
 type Formats []span.Span
@@ -92,6 +94,7 @@ type Data struct {
 	UnimportedCompletions    UnimportedCompletions
 	DeepCompletions          DeepCompletions
 	FuzzyCompletions         FuzzyCompletions
+	CaseSensitiveCompletions CaseSensitiveCompletions
 	RankCompletions          RankCompletions
 	FoldingRanges            FoldingRanges
 	Formats                  Formats
@@ -123,6 +126,7 @@ type Tests interface {
 	UnimportedCompletions(*testing.T, UnimportedCompletions, CompletionItems)
 	DeepCompletions(*testing.T, DeepCompletions, CompletionItems)
 	FuzzyCompletions(*testing.T, FuzzyCompletions, CompletionItems)
+	CaseSensitiveCompletions(*testing.T, CaseSensitiveCompletions, CompletionItems)
 	RankCompletions(*testing.T, RankCompletions, CompletionItems)
 	FoldingRange(*testing.T, FoldingRanges)
 	Format(*testing.T, Formats)
@@ -160,6 +164,9 @@ const (
 	// Fuzzy tests deep completion and fuzzy matching.
 	CompletionFuzzy
 
+	// CaseSensitive tests case sensitive completion
+	CompletionCaseSensitve
+
 	// CompletionRank candidates in test must be valid and in the right relative order.
 	CompletionRank
 )
@@ -217,6 +224,7 @@ func Load(t testing.TB, exporter packagestest.Exporter, dir string) *Data {
 		DeepCompletions:          make(DeepCompletions),
 		FuzzyCompletions:         make(FuzzyCompletions),
 		RankCompletions:          make(RankCompletions),
+		CaseSensitiveCompletions: make(CaseSensitiveCompletions),
 		Definitions:              make(Definitions),
 		Highlights:               make(Highlights),
 		References:               make(References),
@@ -301,6 +309,7 @@ func Load(t testing.TB, exporter packagestest.Exporter, dir string) *Data {
 		"unimported":    data.collectCompletions(CompletionUnimported),
 		"deep":          data.collectCompletions(CompletionDeep),
 		"fuzzy":         data.collectCompletions(CompletionFuzzy),
+		"casesensitive": data.collectCompletions(CompletionCaseSensitve),
 		"rank":          data.collectCompletions(CompletionRank),
 		"snippet":       data.collectCompletionSnippets,
 		"fold":          data.collectFoldingRanges,
@@ -382,6 +391,14 @@ func Run(t *testing.T, tests Tests, data *Data) {
 		tests.FuzzyCompletions(t, data.FuzzyCompletions, data.CompletionItems)
 	})
 
+	t.Run("CaseSensitiveCompletion", func(t *testing.T) {
+		t.Helper()
+		if len(data.CaseSensitiveCompletions) != ExpectedCaseSensitiveCompletionsCount {
+			t.Errorf("got %v case sensitive completions expected %v", len(data.CaseSensitiveCompletions), ExpectedCaseSensitiveCompletionsCount)
+		}
+		tests.CaseSensitiveCompletions(t, data.CaseSensitiveCompletions, data.CompletionItems)
+	})
+
 	t.Run("RankCompletions", func(t *testing.T) {
 		t.Helper()
 		if len(data.RankCompletions) != ExpectedRankedCompletionsCount {
@@ -638,6 +655,10 @@ func (data *Data) collectCompletions(typ CompletionTestType) func(span.Span, []t
 		return func(src span.Span, expected []token.Pos) {
 			result(data.RankCompletions, src, expected)
 		}
+	case CompletionCaseSensitve:
+		return func(src span.Span, expected []token.Pos) {
+			result(data.CaseSensitiveCompletions, src, expected)
+		}
 	default:
 		return func(src span.Span, expected []token.Pos) {
 			result(data.Completions, src, expected)