Use the clang-tidy version in use for check documentation links

Extension/src/LanguageServer/clangTidyDocumentation.ts

@@ -0,0 +1,26 @@
+/* --------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All Rights Reserved.
+ * See 'LICENSE' in the project root for license information.
+ * ------------------------------------------------------------------------------------------ */
+
+/**
+ * The clang-tidy documentation is published per major LLVM release, so a check's page lives
+ * under the .1.0 release of the major the binary in use comes from: 23.1.0 and 22.1.0 have
+ * pages, 23.1.1 and 22.1.3 do not. Checks added in a newer major have no page in an older one,
+ * so the URL follows the binary in use rather than the release bundled with the extension.
+ * When the version in use could not be determined, fall back to the bundled release.
+ */
+export const fallbackClangTidyDocVersion: string = '23.1.0';
+
+const versionPattern: RegExp = /^([0-9]+)\.[0-9]+\.[0-9]+$/;
+
+/** The release a clang-tidy version's documentation was published under. */
+function documentationRelease(clangTidyVersion: string): string | undefined {
+    const match: RegExpMatchArray | null = clangTidyVersion.match(versionPattern);
+    return match ? `${match[1]}.1.0` : undefined;
+}
+
+export function getClangTidyDocumentationUrl(docPage: string, clangTidyVersion?: string): string {
+    const release: string | undefined = clangTidyVersion ? documentationRelease(clangTidyVersion) : undefined;
+    return `https://releases.llvm.org/${release ?? fallbackClangTidyDocVersion}/tools/clang/tools/extra/docs/clang-tidy/${docPage}`;
+}

Extension/src/LanguageServer/codeAnalysis.ts

@@ -6,6 +6,7 @@
 import * as vscode from 'vscode';
 import { NotificationType, Range } from 'vscode-languageclient';
 import * as nls from 'vscode-nls';
+import { getClangTidyDocumentationUrl } from './clangTidyDocumentation';
 import { Location, WorkspaceEdit } from './commonTypes';
 import { CppSourceStr } from './extension';
 import { LanguageClient } from './languageClient';
@@ -379,8 +380,7 @@ export function publishCodeAnalysisDiagnostics(params: PublishCodeAnalysisDiagno
                     const checksPage: string = dashIndex > 0 ? primaryCode.substring(dashIndex + 1) : primaryCode;
                     docPage = `checks${checksGroup}/${checksPage}.html`;
                 }
-                // TODO: This should be checking the clang-tidy version used to better support usage of older versions.
-                const primaryDocUri: vscode.Uri = vscode.Uri.parse(`https://releases.llvm.org/23.1.0/tools/clang/tools/extra/docs/clang-tidy/${docPage}`);
+                const primaryDocUri: vscode.Uri = vscode.Uri.parse(getClangTidyDocumentationUrl(docPage, new CppSettings(realUri).clangTidyVersion));
                 diagnostic.code = { value: identifier.code, target: primaryDocUri };
 
                 if (new CppSettings().clangTidyCodeActionShowDocumentation) {

Extension/src/LanguageServer/settings.ts

@@ -12,7 +12,7 @@ import * as vscode from 'vscode';
 import * as nls from 'vscode-nls';
 import * as which from 'which';
 import * as util from '../common';
-import { getCachedClangFormatPath, getCachedClangTidyPath, getExtensionFilePath, getRawSetting, isArray, isArrayOfString, isBoolean, isNumber, isObject, isString, isValidMapping, setCachedClangFormatPath, setCachedClangTidyPath } from '../common';
+import { getCachedClangFormatPath, getCachedClangTidyPath, getCachedClangTidyVersion, getExtensionFilePath, getRawSetting, isArray, isArrayOfString, isBoolean, isNumber, isObject, isString, isValidMapping, setCachedClangFormatPath, setCachedClangTidyPath, setCachedClangTidyVersion } from '../common';
 import { isWindows } from '../constants';
 import * as telemetry from '../telemetry';
 import { cachedEditorConfigLookups, DefaultClient, hasTrustedCompilerPaths } from './client';
@@ -279,6 +279,14 @@ export class CppSettings extends Settings {
         return this.getClangPath(false);
     }
 
+    public get clangTidyVersion(): string | undefined {
+        // The cached version comes from an auto-discovered binary, so it says nothing about the
+        // clang-tidy a resource carrying its own path is running. Reporting it would point that
+        // resource's documentation links at the wrong release, so leave the version unknown and
+        // let the caller fall back.
+        return changeBlankStringToUndefined(this.getAsStringOrUndefined("codeAnalysis.clangTidy.path")) ? undefined : getCachedClangTidyVersion();
+    }
+
     public get clangFormatPath(): string | undefined {
         return this.getClangPath(true);
     }
@@ -303,6 +311,7 @@ export class CppSettings extends Settings {
             } else {
                 // Attempt to invoke both our own version of clang-* to see if we can successfully execute it, and to get its version.
                 let bundledVersion: string;
+                let clangVersion: string | undefined;
                 try {
                     const bundledPath: string = getExtensionFilePath(`./LLVM/bin/${clangName}`);
                     const output: string = execFileSync(bundledPath, ['--version']).toString();
@@ -322,10 +331,18 @@ export class CppSettings extends Settings {
                     if (semver.ltr(userVersion, bundledVersion)) {
                         path = "";
                         setCachedClangPath(path);
+                        clangVersion = bundledVersion;
+                    } else {
+                        clangVersion = userVersion;
                     }
                 } catch {
                     path = "";
                     setCachedClangPath(path);
+                    clangVersion = bundledVersion;
+                }
+
+                if (!isFormat && clangVersion) {
+                    setCachedClangTidyVersion(clangVersion);
                 }
             }
         }

Extension/src/common.ts

@@ -60,6 +60,15 @@ export function setCachedClangTidyPath(path: string): void {
     cachedClangTidyPath = path;
 }
 
+let cachedClangTidyVersion: string | undefined;
+export function getCachedClangTidyVersion(): string | undefined {
+    return cachedClangTidyVersion;
+}
+
+export function setCachedClangTidyVersion(version: string): void {
+    cachedClangTidyVersion = version;
+}
+
 // Use this package.json to read values
 export const packageJson: any = vscode.extensions.getExtension("ms-vscode.cpptools")?.packageJSON;
 

Extension/test/unit/clangTidyDocumentation.test.ts

@@ -0,0 +1,33 @@
+/* --------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All Rights Reserved.
+ * See 'LICENSE' in the project root for license information.
+ * ------------------------------------------------------------------------------------------ */
+
+import { describe, it } from 'mocha';
+import { strictEqual } from 'node:assert';
+import { fallbackClangTidyDocVersion, getClangTidyDocumentationUrl } from '../../src/LanguageServer/clangTidyDocumentation';
+
+const bundledDocUrl: string = `https://releases.llvm.org/${fallbackClangTidyDocVersion}/tools/clang/tools/extra/docs/clang-tidy`;
+
+describe('clang-tidy documentation URLs', () => {
+    it('points at the clang-tidy version in use', () => {
+        strictEqual(
+            getClangTidyDocumentationUrl('checks/readability/use-std-min-max.html', '19.1.0'),
+            'https://releases.llvm.org/19.1.0/tools/clang/tools/extra/docs/clang-tidy/checks/readability/use-std-min-max.html');
+    });
+
+    it('uses the .1.0 release of that major, since patch releases have no page', () => {
+        strictEqual(
+            getClangTidyDocumentationUrl('checks/readability/use-std-min-max.html', '23.1.1'),
+            'https://releases.llvm.org/23.1.0/tools/clang/tools/extra/docs/clang-tidy/checks/readability/use-std-min-max.html');
+        strictEqual(
+            getClangTidyDocumentationUrl('checks/misc/include-cleaner.html', '22.1.3'),
+            'https://releases.llvm.org/22.1.0/tools/clang/tools/extra/docs/clang-tidy/checks/misc/include-cleaner.html');
+    });
+
+    it('falls back to the bundled version when the version in use is unknown', () => {
+        strictEqual(getClangTidyDocumentationUrl('checks/misc/include-cleaner.html'), `${bundledDocUrl}/checks/misc/include-cleaner.html`);
+        strictEqual(getClangTidyDocumentationUrl('checks/misc/include-cleaner.html', ''), `${bundledDocUrl}/checks/misc/include-cleaner.html`);
+        strictEqual(getClangTidyDocumentationUrl('checks/misc/include-cleaner.html', '23.1'), `${bundledDocUrl}/checks/misc/include-cleaner.html`);
+    });
+});