Try to find a valid dotnet version from the path before falling back to runtime extension

src/lsptoolshost/dotnetRuntimeExtensionResolver.ts

@@ -5,12 +5,17 @@
 
 import * as path from 'path';
 import * as vscode from 'vscode';
+import * as semver from 'semver';
 import { HostExecutableInformation } from '../shared/constants/hostExecutableInformation';
 import { IHostExecutableResolver } from '../shared/constants/IHostExecutableResolver';
 import { PlatformInformation } from '../shared/platform';
 import { Options } from '../shared/options';
 import { existsSync } from 'fs';
 import { CSharpExtensionId } from '../constants/csharpExtensionId';
+import { promisify } from 'util';
+import { exec } from 'child_process';
+import { getDotnetInfo } from '../shared/utils/getDotnetInfo';
+import { readFile } from 'fs/promises';
 
 export const DotNetRuntimeVersion = '7.0';
 
@@ -22,19 +27,36 @@ interface IDotnetAcquireResult {
  * Resolves the dotnet runtime for a server executable from given options and the dotnet runtime VSCode extension.
  */
 export class DotnetRuntimeExtensionResolver implements IHostExecutableResolver {
+    private readonly minimumDotnetVersion = '7.0.100';
     constructor(
         private platformInfo: PlatformInformation,
         /**
          * This is a function instead of a string because the server path can change while the extension is active (when the option changes).
          */
-        private getServerPath: (options: Options, platform: PlatformInformation) => string
+        private getServerPath: (options: Options, platform: PlatformInformation) => string,
+        private channel: vscode.OutputChannel,
+        private extensionPath: string
     ) {}
 
     private hostInfo: HostExecutableInformation | undefined;
 
     async getHostExecutableInfo(options: Options): Promise<HostExecutableInformation> {
         let dotnetRuntimePath = options.commonOptions.dotnetPath;
         const serverPath = this.getServerPath(options, this.platformInfo);
+
+        // Check if we can find a valid dotnet from dotnet --version on the PATH.
+        if (!dotnetRuntimePath) {
+            const dotnetPath = await this.findDotnetFromPath();
+            if (dotnetPath) {
+                return {
+                    version: '' /* We don't need to know the version - we've already verified its high enough */,
+                    path: dotnetPath,
+                    env: process.env,
+                };
+            }
+        }
+
+        // We didn't find it on the path, see if we can install the correct runtime using the runtime extension.
         if (!dotnetRuntimePath) {
             const dotnetInfo = await this.acquireDotNetProcessDependencies(serverPath);
             dotnetRuntimePath = path.dirname(dotnetInfo.path);
@@ -101,4 +123,103 @@ export class DotnetRuntimeExtensionResolver implements IHostExecutableResolver {
 
         return dotnetInfo;
     }
+
+    /**
+     * Checks dotnet --version to see if the value on the path is greater than the minimum required version.
+     * This is adapated from similar O# server logic and should be removed when we have a stable acquisition extension.
+     * @returns true if the dotnet version is greater than the minimum required version, false otherwise.
+     */
+    private async findDotnetFromPath(): Promise<string | undefined> {
+        try {
+            const dotnetInfo = await getDotnetInfo([]);
+            const dotnetVersionStr = dotnetInfo.Version;
+
+            const extensionArchitecture = await this.getArchitectureFromTargetPlatform();
+            const dotnetArchitecture = dotnetInfo.Architecture;
+
+            // If the extension arhcitecture is defined, we check that it matches the dotnet architecture.
+            // If its undefined we likely have a platform neutral server and assume it can run on any architecture.
+            if (extensionArchitecture && extensionArchitecture !== dotnetArchitecture) {
+                throw new Error(
+                    `The architecture of the .NET runtime (${dotnetArchitecture}) does not match the architecture of the extension (${extensionArchitecture}).`
+                );
+            }
+
+            const dotnetVersion = semver.parse(dotnetVersionStr);
+            if (!dotnetVersion) {
+                throw new Error(`Unknown result output from 'dotnet --version'. Received ${dotnetVersionStr}`);
+            }
+
+            if (semver.lt(dotnetVersion, this.minimumDotnetVersion)) {
+                throw new Error(
+                    `Found dotnet version ${dotnetVersion}. Minimum required version is ${this.minimumDotnetVersion}.`
+                );
+            }
+
+            // Find the location of the dotnet on path.
+            const command = this.platformInfo.isWindows() ? 'where' : 'which';
+            const whereOutput = await promisify(exec)(`${command} dotnet`);
+            if (!whereOutput.stdout) {
+                throw new Error(`Unable to find dotnet from ${command}.`);
+            }
+
+            const path = whereOutput.stdout.trim();
+            if (!existsSync(path)) {
+                throw new Error(`dotnet path does not exist: ${path}`);
+            }
+
+            this.channel.appendLine(`Using dotnet configured on PATH`);
+            return path;
+        } catch (e) {
+            this.channel.appendLine(
+                'Failed to find dotnet info from path, falling back to acquire runtime via ms-dotnettools.vscode-dotnet-runtime'
+            );
+            if (e instanceof Error) {
+                this.channel.appendLine(e.message);
+            }
+        }
+
+        return undefined;
+    }
+
+    private async getArchitectureFromTargetPlatform(): Promise<string | undefined> {
+        const vsixManifestFile = path.join(this.extensionPath, '.vsixmanifest');
+        if (!existsSync(vsixManifestFile)) {
+            // This is not an error as normal development F5 builds do not generate a .vsixmanifest file.
+            this.channel.appendLine(
+                `Unable to find extension target platform - no vsix manifest file exists at ${vsixManifestFile}`
+            );
+            return undefined;
+        }
+
+        const contents = await readFile(vsixManifestFile, 'utf-8');
+        const targetPlatformMatch = /TargetPlatform="(.*)"/.exec(contents);
+        if (!targetPlatformMatch) {
+            throw new Error(`Could not find extension target platform in ${vsixManifestFile}`);
+        }
+
+        const targetPlatform = targetPlatformMatch[1];
+
+        // The currently known extension platforms are taken from here:
+        // https://code.visualstudio.com/api/working-with-extensions/publishing-extension#platformspecific-extensions
+        switch (targetPlatform) {
+            case 'win32-x64':
+            case 'linux-x64':
+            case 'alpine-x64':
+            case 'darwin-x64':
+                return 'x64';
+            case 'win32-ia32':
+                return 'x86';
+            case 'win32-arm64':
+            case 'linux-arm64':
+            case 'alpine-arm64':
+            case 'darwin-arm64':
+                return 'arm64';
+            case 'linux-armhf':
+            case 'web':
+                return undefined;
+            default:
+                throw new Error(`Unknown extension target platform: ${targetPlatform}`);
+        }
+    }
 }

src/lsptoolshost/roslynLanguageServer.ts

@@ -733,7 +733,12 @@ export async function activateRoslynLanguageServer(
     // Create a separate channel for outputting trace logs - these are incredibly verbose and make other logs very difficult to see.
     _traceChannel = vscode.window.createOutputChannel('C# LSP Trace Logs');
 
-    const hostExecutableResolver = new DotnetRuntimeExtensionResolver(platformInfo, getServerPath);
+    const hostExecutableResolver = new DotnetRuntimeExtensionResolver(
+        platformInfo,
+        getServerPath,
+        outputChannel,
+        context.extensionPath
+    );
     const additionalExtensionPaths = scanExtensionPlugins();
     _languageServer = new RoslynLanguageServer(
         platformInfo,

src/shared/utils/dotnetInfo.ts

@@ -9,4 +9,5 @@ export interface DotnetInfo {
     Version: string;
     /* a runtime-only install of dotnet will not output a runtimeId in dotnet --info. */
     RuntimeId?: string;
+    Architecture?: string;
 }

src/shared/utils/getDotnetInfo.ts

@@ -26,6 +26,7 @@ export async function getDotnetInfo(dotNetCliPaths: string[]): Promise<DotnetInf
 
         let version: string | undefined;
         let runtimeId: string | undefined;
+        let architecture: string | undefined;
 
         const lines = data.replace(/\r/gm, '').split('\n');
         for (const line of lines) {
@@ -34,6 +35,8 @@ export async function getDotnetInfo(dotNetCliPaths: string[]): Promise<DotnetInf
                 version = match[1];
             } else if ((match = /^ RID:\s*([\w\-.]+)$/.exec(line))) {
                 runtimeId = match[1];
+            } else if ((match = /^\s*Architecture:\s*(.*)/.exec(line))) {
+                architecture = match[1];
             }
         }
 
@@ -43,6 +46,7 @@ export async function getDotnetInfo(dotNetCliPaths: string[]): Promise<DotnetInf
                 FullInfo: fullInfo,
                 Version: version,
                 RuntimeId: runtimeId,
+                Architecture: architecture,
             };
             return _dotnetInfo;
         }