From f479de6d02328156ede70c6e7de9f50cd16a4fac Mon Sep 17 00:00:00 2001
From: Andy <anhans@microsoft.com>
Date: Tue, 10 Apr 2018 14:38:16 -0700
Subject: [PATCH] patternMatcher: Just return 'undefined' for an invalid
 pattern (#23237)

* patternMatcher: Just return 'undefined' for an invalid pattern

* Fix tests
---
 .../unittests/services/patternMatcher.ts      | 12 +++++-----
 src/services/navigateTo.ts                    |  1 +
 src/services/patternMatcher.ts                | 23 +++++--------------
 3 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/src/harness/unittests/services/patternMatcher.ts b/src/harness/unittests/services/patternMatcher.ts
index a3e2d1d5cff..5aee5d2f4eb 100644
--- a/src/harness/unittests/services/patternMatcher.ts
+++ b/src/harness/unittests/services/patternMatcher.ts
@@ -343,15 +343,11 @@ describe("PatternMatcher", () => {
         });
 
         it("BlankPattern", () => {
-            const matches = getAllMatches("AddMetadataReference", "");
-
-            assert.isTrue(matches === undefined);
+            assertInvalidPattern("");
         });
 
         it("WhitespaceOnlyPattern", () => {
-            const matches = getAllMatches("AddMetadataReference", " ");
-
-            assert.isTrue(matches === undefined);
+            assertInvalidPattern(" ");
         });
 
         it("EachWordSeparately1", () => {
@@ -449,6 +445,10 @@ describe("PatternMatcher", () => {
         });
     });
 
+    function assertInvalidPattern(pattern: string) {
+        assert.equal(ts.createPatternMatcher(pattern), undefined);
+    }
+
     function getFirstMatch(candidate: string, pattern: string): ts.PatternMatch {
         const matches = ts.createPatternMatcher(pattern).getMatchesForLastSegmentOfPattern(candidate);
         return matches ? matches[0] : undefined;
diff --git a/src/services/navigateTo.ts b/src/services/navigateTo.ts
index 1a556cf33c0..4713f89dbde 100644
--- a/src/services/navigateTo.ts
+++ b/src/services/navigateTo.ts
@@ -10,6 +10,7 @@ namespace ts.NavigateTo {
 
     export function getNavigateToItems(sourceFiles: ReadonlyArray<SourceFile>, checker: TypeChecker, cancellationToken: CancellationToken, searchValue: string, maxResultCount: number, excludeDtsFiles: boolean): NavigateToItem[] {
         const patternMatcher = createPatternMatcher(searchValue);
+        if (!patternMatcher) return emptyArray;
         let rawItems: RawNavigateToItem[] = [];
 
         // Search the declarations in all files and output matched NavigateToItem into array of NavigateToItem[]
diff --git a/src/services/patternMatcher.ts b/src/services/patternMatcher.ts
index 612fa57378d..84ef1244040 100644
--- a/src/services/patternMatcher.ts
+++ b/src/services/patternMatcher.ts
@@ -97,28 +97,22 @@ namespace ts {
         };
     }
 
-    export function createPatternMatcher(pattern: string): PatternMatcher {
+    export function createPatternMatcher(pattern: string): PatternMatcher | undefined {
         // We'll often see the same candidate string many times when searching (For example, when
         // we see the name of a module that is used everywhere, or the name of an overload).  As
         // such, we cache the information we compute about the candidate for the life of this
         // pattern matcher so we don't have to compute it multiple times.
         const stringToWordSpans = createMap<TextSpan[]>();
 
-        pattern = pattern.trim();
-
-        const dotSeparatedSegments = pattern.split(".").map(p => createSegment(p.trim()));
-        const invalidPattern = dotSeparatedSegments.length === 0 || forEach(dotSeparatedSegments, segmentIsInvalid);
+        const dotSeparatedSegments = pattern.trim().split(".").map(p => createSegment(p.trim()));
+        // A segment is considered invalid if we couldn't find any words in it.
+        if (dotSeparatedSegments.some(segment => !segment.subWordTextChunks.length)) return undefined;
 
         return {
-            getMatches: (containers, candidate) => skipMatch(candidate) ? undefined : getMatches(containers, candidate, dotSeparatedSegments, stringToWordSpans),
-            getMatchesForLastSegmentOfPattern: candidate => skipMatch(candidate) ? undefined : matchSegment(candidate, lastOrUndefined(dotSeparatedSegments), stringToWordSpans),
+            getMatches: (containers, candidate) => getMatches(containers, candidate, dotSeparatedSegments, stringToWordSpans),
+            getMatchesForLastSegmentOfPattern: candidate => matchSegment(candidate, last(dotSeparatedSegments), stringToWordSpans),
             patternContainsDots: dotSeparatedSegments.length > 1
         };
-
-        // Quick checks so we can bail out when asked to match a candidate.
-        function skipMatch(candidate: string) {
-            return invalidPattern || !candidate;
-        }
     }
 
     function getMatches(candidateContainers: ReadonlyArray<string>, candidate: string, dotSeparatedSegments: ReadonlyArray<Segment>, stringToWordSpans: Map<TextSpan[]>): PatternMatch[] | undefined {
@@ -381,11 +375,6 @@ namespace ts {
         };
     }
 
-    // A segment is considered invalid if we couldn't find any words in it.
-    function segmentIsInvalid(segment: Segment) {
-        return segment.subWordTextChunks.length === 0;
-    }
-
     function isUpperCaseLetter(ch: number) {
         // Fast check for the ascii range.
         if (ch >= CharacterCodes.A && ch <= CharacterCodes.Z) {