Fix issue where syntax highlighting crashes on create constraint query (

#139)
neo4j · Nov 22, 2023 · a790700 · a790700
1 parent 4309a0e
commit a790700
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diff --git a/.changeset/purple-suns-applaud.md b/.changeset/purple-suns-applaud.md
@@ -0,0 +1,5 @@
+---
+'@neo4j-cypher/language-support': patch
+---
+
+Fix issue where syntax highlighting crashes on create constraint query
diff --git a/packages/language-support/src/highlighting/syntaxColouring/syntaxColouring.ts b/packages/language-support/src/highlighting/syntaxColouring/syntaxColouring.ts
@@ -115,9 +115,12 @@ class SyntaxHighlighter extends CypherParserListener {
   };
 
   exitLabelOrRelType = (ctx: LabelOrRelTypeContext) => {
-    const labelName = ctx.symbolicNameString().start;
-
-    this.addToken(labelName, CypherTokenType.label, labelName.text);
+    // Error recovery can insert a LabelOrRelType node with no text
+    // See for example CREATE CONSTRAINT FOR (node)
+    const labelName = ctx.symbolicNameString()?.start;
+    if (labelName) {
+      this.addToken(labelName, CypherTokenType.label, labelName.text);
+    }
   };
 
   exitLeftArrow = (ctx: LeftArrowContext) => {

diff --git a/packages/language-support/src/tests/highlighting/syntaxColouring/clauses.test.ts b/packages/language-support/src/tests/highlighting/syntaxColouring/clauses.test.ts
@@ -2121,3 +2121,83 @@ describe('Subqueries colouring', () => {
     ]);
   });
 });
+
+describe('CREATE colouring', () => {
+  test('correctly highlight broken create constraint', () => {
+    // is missing :Label, should not crash
+    expect(applySyntaxColouring('CREATE CONSTRAINT FOR (node)')).toEqual([
+      {
+        bracketInfo: undefined,
+        length: 6,
+        position: {
+          line: 0,
+          startCharacter: 0,
+          startOffset: 0,
+        },
+        token: 'CREATE',
+        tokenType: 'keyword',
+      },
+      {
+        bracketInfo: undefined,
+        length: 10,
+        position: {
+          line: 0,
+          startCharacter: 7,
+          startOffset: 7,
+        },
+        token: 'CONSTRAINT',
+        tokenType: 'keyword',
+      },
+      {
+        bracketInfo: undefined,
+        length: 3,
+        position: {
+          line: 0,
+          startCharacter: 18,
+          startOffset: 18,
+        },
+        token: 'FOR',
+        tokenType: 'keyword',
+      },
+      {
+        bracketInfo: {
+          bracketLevel: 0,
+          bracketType: 'parenthesis',
+        },
+        length: 1,
+        position: {
+          line: 0,
+          startCharacter: 22,
+          startOffset: 22,
+        },
+        token: '(',
+        tokenType: 'bracket',
+      },
+      {
+        bracketInfo: undefined,
+        length: 4,
+        position: {
+          line: 0,
+          startCharacter: 23,
+          startOffset: 23,
+        },
+        token: 'node',
+        tokenType: 'variable',
+      },
+      {
+        bracketInfo: {
+          bracketLevel: 0,
+          bracketType: 'parenthesis',
+        },
+        length: 1,
+        position: {
+          line: 0,
+          startCharacter: 27,
+          startOffset: 27,
+        },
+        token: ')',
+        tokenType: 'bracket',
+      },
+    ]);
+  });
+});