From 996b3cd6a8f747692581057e558f8cd9e5f066ee Mon Sep 17 00:00:00 2001
From: Sean McManus <seanmcm@microsoft.com>
Date: Thu, 13 Aug 2026 19:27:29 +0000
Subject: [PATCH] Fix configuration path diagnostic ranges

---
 .../src/LanguageServer/configurations.ts      |  8 ++---
 Extension/src/Utility/Text/escape.ts          |  5 ++++
 Extension/test/unit/escape.test.ts            | 30 +++++++++++++++++--
 3 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/Extension/src/LanguageServer/configurations.ts b/Extension/src/LanguageServer/configurations.ts
index dc52a6cdd..f2d1ec4f4 100644
--- a/Extension/src/LanguageServer/configurations.ts
+++ b/Extension/src/LanguageServer/configurations.ts
@@ -14,7 +14,7 @@ import * as vscode from 'vscode';
 import * as nls from 'vscode-nls';
 import * as which from 'which';
 import { logAndReturn, returns } from '../Utility/Async/returns';
-import { escapePathForSquiggles } from '../Utility/Text/escape';
+import { escapePathForSquiggles, getTextMatchOffsets } from '../Utility/Text/escape';
 import * as util from '../common';
 import { isWindows } from '../constants';
 import { getOutputChannelLogger } from '../logger';
@@ -2134,8 +2134,7 @@ export class CppProperties {
                 expandedPaths = result ?? [];
                 if (duration > 10 && configMatches) {
                     newSquiggleMetrics.SlowPathResolution++;
-                    const curOffset = curText.indexOf(configMatches[0]);
-                    const endOffset = curOffset + curPath.length;
+                    const [curOffset, endOffset] = getTextMatchOffsets(curText, configMatches[0]);
                     const diagnostic: vscode.Diagnostic = new vscode.Diagnostic(
                         new vscode.Range(document.positionAt(curTextStartOffset + curOffset), document.positionAt(curTextStartOffset + endOffset)),
                         localize('resolve.path.took.too.long', "Path took {0}s to evaluate", duration),
@@ -2145,8 +2144,7 @@ export class CppProperties {
             } catch (e) {
                 expandedPaths = [];
                 if (configMatches) {
-                    const curOffset = curText.indexOf(configMatches[0]);
-                    const endOffset = curOffset + curPath.length;
+                    const [curOffset, endOffset] = getTextMatchOffsets(curText, configMatches[0]);
                     const diagnostic: vscode.Diagnostic = new vscode.Diagnostic(
                         new vscode.Range(document.positionAt(curTextStartOffset + curOffset), document.positionAt(curTextStartOffset + endOffset)),
                         localize('resolve.path.failed', "Failed to resolve path {0}. Error: {1}", curPath, (e as Error).message),
diff --git a/Extension/src/Utility/Text/escape.ts b/Extension/src/Utility/Text/escape.ts
index d4e815ec8..243ac362b 100644
--- a/Extension/src/Utility/Text/escape.ts
+++ b/Extension/src/Utility/Text/escape.ts
@@ -7,3 +7,8 @@ export function escapePathForSquiggles(s: string): string {
     return s.replace(/[-"\/\\^$*+?.()|[\]{}]/g, (character: string): string =>
         character === '"' ? '\\\\"' : `\\${character}`);
 }
+
+export function getTextMatchOffsets(text: string, match: string): [number, number] {
+    const startOffset: number = text.indexOf(match);
+    return [startOffset, startOffset + match.length];
+}
diff --git a/Extension/test/unit/escape.test.ts b/Extension/test/unit/escape.test.ts
index 716eab97a..2e3982e23 100644
--- a/Extension/test/unit/escape.test.ts
+++ b/Extension/test/unit/escape.test.ts
@@ -4,8 +4,8 @@
  * ------------------------------------------------------------------------------------------ */
 
 import { describe, it } from 'mocha';
-import { doesNotMatch, match, strictEqual } from 'node:assert';
-import { escapePathForSquiggles } from '../../src/Utility/Text/escape';
+import { deepStrictEqual, doesNotMatch, match, ok, strictEqual } from 'node:assert';
+import { escapePathForSquiggles, getTextMatchOffsets } from '../../src/Utility/Text/escape';
 
 describe('Text escaping', () => {
     it('escapes paths for matching their JSON spelling', () => {
@@ -29,4 +29,30 @@ describe('Text escaping', () => {
         doesNotMatch(String.raw`C:\sdk\[headers]+(x)?.h\say\"hello\"and\"goodbye`, pattern);
         doesNotMatch(String.raw`C:\\sdk\\headers+(x)?.h\\say\"hello\"and\"goodbye`, pattern);
     });
+
+    it('uses the full source match for a non-first semicolon-delimited path', () => {
+        const parsedPath: string = 'second';
+        const sourceMatch: string = '"first;second;third"';
+        const text: string = `"includePath": [${sourceMatch}]`;
+        const pattern: RegExp = new RegExp(`"[^"]*?(?<="|;)${escapePathForSquiggles(parsedPath)}(?="|;).*?"`, 'g');
+        const matches: string[] | null = text.match(pattern);
+
+        ok(matches);
+        strictEqual(matches?.[0], sourceMatch);
+        const startOffset: number = text.indexOf(sourceMatch);
+        deepStrictEqual(getTextMatchOffsets(text, matches[0]), [startOffset, startOffset + sourceMatch.length]);
+    });
+
+    it('uses the JSON source length when it differs from the parsed path', () => {
+        const parsedPath: string = 'folder"quoted"';
+        const sourceMatch: string = String.raw`"folder\"quoted\""`;
+        const text: string = `"includePath": [${sourceMatch}]`;
+        const pattern: RegExp = new RegExp(`"[^"]*?(?<="|;)${escapePathForSquiggles(parsedPath)}(?="|;).*?"`, 'g');
+        const matches: string[] | null = text.match(pattern);
+
+        ok(matches);
+        strictEqual(matches?.[0], sourceMatch);
+        const startOffset: number = text.indexOf(sourceMatch);
+        deepStrictEqual(getTextMatchOffsets(text, matches[0]), [startOffset, startOffset + sourceMatch.length]);
+    });
 });