Gate plugins on CLI flag

src/compiler/commandLineParser.ts

@@ -500,6 +500,15 @@ export const commonOptionsWithBuild: CommandLineOption[] = [
         description: Diagnostics.Set_the_language_of_the_messaging_from_TypeScript_This_does_not_affect_emit,
         defaultValueDescription: Diagnostics.Platform_specific
     },
+    {
+        name: "allowPlugins",
+        type: "boolean",
+        affectsSemanticDiagnostics: true,
+        affectsEmit: true,
+        affectsBuildInfo: true,
+        defaultValueDescription: undefined,
+        isCommandLineOnly: true,
+    },
 ];
 
 /** @internal */

src/compiler/diagnosticMessages.json

@@ -6236,6 +6236,10 @@
       "category": "Error",
       "code": 6931
     },
+    "Option '--allowPlugins' must be specified when compiler plugins are present.": {
+        "category": "Error",
+        "code": 6932
+    },
 
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",

src/compiler/pluginUtilities.ts

@@ -1,3 +1,5 @@
+import type { CompilerOptions } from "./types";
+
 /** @internal */
 export type Entrypoint = "tsc" | "typescript" | "tsserver" | "tsserverlibrary" | "testRunner";
 
@@ -16,3 +18,14 @@ export function getTypeScriptNamespace(): any {
     if (currentTsNamespace === undefined) throw new Error("ts namespace unset");
     return currentTsNamespace;
 }
+
+/** @internal */
+export function shouldAllowPlugins(options: CompilerOptions): boolean {
+    switch (currentEntrypoint) {
+        case "tsserver":
+        case "tsserverlibrary":
+        case "typescript":
+            return true;
+    }
+    return options.allowPlugins ?? false;
+}

src/compiler/program.ts

@@ -294,6 +294,7 @@ import {
     setParentRecursive,
     setResolvedModule,
     setResolvedTypeReferenceDirective,
+    shouldAllowPlugins,
     shouldResolveJsRequire,
     skipTrivia,
     skipTypeChecking,
@@ -2712,6 +2713,10 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
         }
 
         const compilerOptions = program.getCompilerOptions();
+        if (!shouldAllowPlugins(compilerOptions)) {
+            return emptyArray;
+        }
+
         const customTransformers = mapDefined(compilerOptions.plugins, config => {
             if (config.type !== "transformer") return undefined;
 
@@ -4444,6 +4449,14 @@ export function createProgram(rootNamesOrOptions: readonly string[] | CreateProg
             });
         }
 
+        if (options.plugins && !shouldAllowPlugins(options)) {
+            for (const plugin of options.plugins) {
+                if (plugin.type === undefined) continue; // Language service plugins. TODO(jakebailey): give these a type, require type, deprecate missing type?
+                programDiagnostics.add(createCompilerDiagnostic(Diagnostics.Option_allowPlugins_must_be_specified_when_compiler_plugins_are_present));
+                break;
+            }
+        }
+
         // Verify that all the emit files are unique and don't overwrite input files
         function verifyEmitFilePath(emitFileName: string | undefined, emitFilesSeen: Set<string>) {
             if (emitFileName) {

src/compiler/tsbuildPublic.ts

@@ -162,6 +162,7 @@ export interface BuildOptions {
     /** @internal */ locale?: string;
     /** @internal */ generateCpuProfile?: string;
     /** @internal */ generateTrace?: string;
+    allowPlugins?: boolean;
 
     [option: string]: CompilerOptionsValue | undefined;
 }

src/compiler/types.ts

@@ -7234,6 +7234,7 @@ export interface CompilerOptions {
     /** @internal */ showConfig?: boolean;
     useDefineForClassFields?: boolean;
     customTransformers?: string[];
+    allowPlugins?: boolean;
 
     [option: string]: CompilerOptionsValue | TsConfigSourceFile | undefined;
 }

tests/baselines/reference/api/tsclibrary.d.ts

@@ -3141,6 +3141,7 @@ declare namespace ts {
         esModuleInterop?: boolean;
         useDefineForClassFields?: boolean;
         customTransformers?: string[];
+        allowPlugins?: boolean;
         [option: string]: CompilerOptionsValue | TsConfigSourceFile | undefined;
     }
     interface WatchOptions {
@@ -5735,6 +5736,7 @@ declare namespace ts {
         sourceMap?: boolean;
         inlineSourceMap?: boolean;
         traceResolution?: boolean;
+        allowPlugins?: boolean;
         [option: string]: CompilerOptionsValue | undefined;
     }
     type ReportEmitErrorSummary = (errorCount: number, filesInError: (ReportFileInError | undefined)[]) => void;

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -7273,6 +7273,7 @@ declare namespace ts {
         esModuleInterop?: boolean;
         useDefineForClassFields?: boolean;
         customTransformers?: string[];
+        allowPlugins?: boolean;
         [option: string]: CompilerOptionsValue | TsConfigSourceFile | undefined;
     }
     interface WatchOptions {
@@ -9870,6 +9871,7 @@ declare namespace ts {
         sourceMap?: boolean;
         inlineSourceMap?: boolean;
         traceResolution?: boolean;
+        allowPlugins?: boolean;
         [option: string]: CompilerOptionsValue | undefined;
     }
     type ReportEmitErrorSummary = (errorCount: number, filesInError: (ReportFileInError | undefined)[]) => void;

tests/baselines/reference/api/typescript.d.ts

@@ -3226,6 +3226,7 @@ declare namespace ts {
         esModuleInterop?: boolean;
         useDefineForClassFields?: boolean;
         customTransformers?: string[];
+        allowPlugins?: boolean;
         [option: string]: CompilerOptionsValue | TsConfigSourceFile | undefined;
     }
     interface WatchOptions {
@@ -5823,6 +5824,7 @@ declare namespace ts {
         sourceMap?: boolean;
         inlineSourceMap?: boolean;
         traceResolution?: boolean;
+        allowPlugins?: boolean;
         [option: string]: CompilerOptionsValue | undefined;
     }
     type ReportEmitErrorSummary = (errorCount: number, filesInError: (ReportFileInError | undefined)[]) => void;

tests/baselines/reference/config/showConfig/Shows tsconfig for single option/allowPlugins/tsconfig.json

@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "allowPlugins": true
+    }
+}