feat: CLI command to run validation (#820)

Closes #703

### Summary of Changes

Add a new `check` command to validate Safe-DS files without generating
code for them.

packages/safe-ds-cli/README.md

@@ -4,10 +4,11 @@
 Usage: cli [options] [command]
 
 Options:
--V, --version              output the version number
--h, --help                 display help for command
+  -V, --version                  output the version number
+  -h, --help                     display help for command
 
 Commands:
-generate [options] <file>  generate Python code
-help [command]             display help for command
+  check [options] <paths...>     check Safe-DS code
+  generate [options] <paths...>  generate Python code
+  help [command]                 display help for command
 ```

packages/safe-ds-cli/package.json

@@ -43,10 +43,13 @@
         "@safe-ds/lang": ">=0.3.0",
         "chalk": "^5.3.0",
         "commander": "^11.1.0",
-        "langium": "^2.1.3"
+        "glob": "^10.3.10",
+        "langium": "^2.1.3",
+        "true-myth": "^7.1.0"
     },
     "devDependencies": {
-        "@types/node": "^18.18.12"
+        "@types/node": "^18.18.12",
+        "vscode-languageserver": "^9.0.1"
     },
     "engines": {
         "node": ">=18.0.0"

packages/safe-ds-cli/src/cli/check.ts

@@ -0,0 +1,47 @@
+import { createSafeDsServicesWithBuiltins } from '@safe-ds/lang';
+import { NodeFileSystem } from 'langium/node';
+import { extractDocuments } from '../helpers/documents.js';
+import { diagnosticToString, getDiagnostics } from '../helpers/diagnostics.js';
+import { Diagnostic, DiagnosticSeverity } from 'vscode-languageserver';
+import chalk from 'chalk';
+import { ExitCode } from './exitCode.js';
+
+export const check = async (fsPaths: string[], options: CheckOptions): Promise<void> => {
+    const services = (await createSafeDsServicesWithBuiltins(NodeFileSystem)).SafeDs;
+
+    let errorCount = 0;
+
+    for (const document of await extractDocuments(services, fsPaths)) {
+        for (const diagnostic of getDiagnostics(document)) {
+            console.log(diagnosticToString(document.uri, diagnostic, options));
+
+            if (isError(diagnostic, options)) {
+                errorCount++;
+            }
+        }
+    }
+
+    if (errorCount > 0) {
+        console.error(chalk.red(`Found ${errorCount} ${errorCount === 1 ? 'error' : 'errors'}.`));
+        process.exit(ExitCode.FileHasErrors);
+    } else {
+        console.log(chalk.green(`No errors found.`));
+    }
+};
+
+/**
+ * Command line options for the `check` command.
+ */
+export interface CheckOptions {
+    /**
+     * Whether the program should fail on warnings.
+     */
+    strict: boolean;
+}
+
+const isError = (diagnostic: Diagnostic, options: CheckOptions) => {
+    return (
+        diagnostic.severity === DiagnosticSeverity.Error ||
+        (diagnostic.severity === DiagnosticSeverity.Warning && options.strict)
+    );
+};

packages/safe-ds-cli/src/cli/exitCode.ts

@@ -0,0 +1,29 @@
+/**
+ * Exit codes for the CLI.
+ */
+export enum ExitCode {
+    /**
+     * Everything went well.
+     */
+    Success = 0,
+
+    /**
+     * The given path does not exist.
+     */
+    MissingPath = 100,
+
+    /**
+     * The given path is not a file or directory.
+     */
+    NotAFileOrDirectory = 101,
+
+    /**
+     * The given file does not have a Safe-DS extension.
+     */
+    FileWithoutSafeDsExtension = 102,
+
+    /**
+     * The given file has errors.
+     */
+    FileHasErrors = 103,
+}

packages/safe-ds-cli/src/cli/generate.ts

@@ -4,32 +4,40 @@ import { URI } from 'langium';
 import { NodeFileSystem } from 'langium/node';
 import fs from 'node:fs';
 import path from 'node:path';
-import { extractDocument } from './cli-util.js';
+import { extractDocuments } from '../helpers/documents.js';
+import { makeParentDirectoriesSync } from '../helpers/files.js';
+import { exitIfDocumentHasErrors } from '../helpers/diagnostics.js';
 
-export const generate = async (fileName: string, opts: CliGenerateOptions): Promise<void> => {
+export const generate = async (fsPaths: string[], options: GenerateOptions): Promise<void> => {
     const services = (await createSafeDsServicesWithBuiltins(NodeFileSystem)).SafeDs;
-    const document = await extractDocument(fileName, services);
-    const destination = opts.destination ?? path.join(path.dirname(fileName), 'generated');
-    const generatedFiles = services.generation.PythonGenerator.generate(document, {
-        destination: URI.file(path.resolve(destination)),
-        createSourceMaps: opts.sourcemaps,
-    });
+    const documents = await extractDocuments(services, fsPaths);
 
-    for (const file of generatedFiles) {
-        const fsPath = URI.parse(file.uri).fsPath;
-        const parentDirectoryPath = path.dirname(fsPath);
-        if (!fs.existsSync(parentDirectoryPath)) {
-            fs.mkdirSync(parentDirectoryPath, { recursive: true });
-        }
+    // Exit if any document has errors before generating code
+    for (const document of documents) {
+        exitIfDocumentHasErrors(document);
+    }
 
-        fs.writeFileSync(fsPath, file.getText());
+    // Generate code
+    for (const document of documents) {
+        const generatedFiles = services.generation.PythonGenerator.generate(document, {
+            destination: URI.file(path.resolve(options.out)),
+            createSourceMaps: options.sourcemaps,
+        });
+
+        for (const file of generatedFiles) {
+            const fsPath = URI.parse(file.uri).fsPath;
+            makeParentDirectoriesSync(fsPath);
+            fs.writeFileSync(fsPath, file.getText());
+        }
     }
 
     console.log(chalk.green(`Python code generated successfully.`));
 };
 
-export interface CliGenerateOptions {
-    destination?: string;
+/**
+ * Command line options for the `generate` command.
+ */
+export interface GenerateOptions {
+    out: string;
     sourcemaps: boolean;
-    quiet: boolean;
 }

packages/safe-ds-cli/src/cli/main.ts

@@ -1,27 +1,29 @@
-import { SafeDsLanguageMetaData } from '@safe-ds/lang';
 import { Command } from 'commander';
 import { createRequire } from 'node:module';
-import { fileURLToPath } from 'url';
+import { fileURLToPath } from 'node:url';
 import { generate } from './generate.js';
-
-const fileExtensions = SafeDsLanguageMetaData.fileExtensions.join(', ');
+import { check } from './check.js';
 
 const program = new Command();
 
 // Version command
 const packagePath = fileURLToPath(new URL('../../package.json', import.meta.url));
 const require = createRequire(import.meta.url);
+program.version(require(packagePath).version);
+
+// Check command
 program
-    // eslint-disable-next-line @typescript-eslint/no-var-requires
-    .version(require(packagePath).version);
+    .command('check')
+    .argument('<paths...>', `list of files or directories to check`)
+    .option('-s, --strict', 'whether the program should fail on warnings', false)
+    .description('check Safe-DS code')
+    .action(check);
 
 // Generate command
 program
     .command('generate')
-    .argument('<file>', `possible file extensions: ${fileExtensions}`)
-    .option('-d, --destination <dir>', 'destination directory of generation')
-    .option('-r, --root <dir>', 'source root folder')
-    .option('-q, --quiet', 'whether the program should print something', false)
+    .argument('<paths...>', `list of files or directories to generate Python code for`)
+    .option('-o, --out <dir>', 'destination directory for generation', 'generated')
     .option('-s, --sourcemaps', 'whether source maps should be generated', false)
     .description('generate Python code')
     .action(generate);