Deprecate baseUrl compiler option in TypeScript 6.0

src/compiler/program.ts

@@ -4529,6 +4529,9 @@ export function createProgram(_rootNamesOrOptions: readonly string[] | CreatePro
             if (options.moduleResolution === ModuleResolutionKind.Node10) {
                 createDeprecatedDiagnostic("moduleResolution", "node10");
             }
+            if (options.baseUrl) {
+                createDeprecatedDiagnostic("baseUrl");
+            }
         });
     }
 

tests/baselines/reference/baseUrlMigrationExample.errors.txt

@@ -0,0 +1,58 @@
+/before/tsconfig.json(3,9): error TS5101: Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0. Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.
+
+
+==== /before/tsconfig.json (1 errors) ====
+    {
+        "compilerOptions": {
+            "baseUrl": "./src",
+            ~~~~~~~~~
+!!! error TS5101: Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0. Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.
+            "paths": {
+                "@app/*": ["app/*"],
+                "@lib/*": ["lib/*"]
+            }
+        }
+    }
+
+==== /before/src/app/module.ts (0 errors) ====
+    export const value = 42;
+
+==== /before/src/lib/utils.ts (0 errors) ====
+    export function helper() { return "help"; }
+
+==== /before/src/main.ts (0 errors) ====
+    import { value } from "@app/module";
+    import { helper } from "@lib/utils";
+    // This would also resolve due to baseUrl:
+    import * as something from "someModule"; // Resolves to ./src/someModule
+
+==== /before/src/someModule.ts (0 errors) ====
+    export const data = "from baseUrl resolution";
+
+==== /after/tsconfig.json (0 errors) ====
+    {
+        "compilerOptions": {
+            "paths": {
+                // Explicit prefix for all path mappings
+                "@app/*": ["./src/app/*"],
+                "@lib/*": ["./src/lib/*"],
+                // Optional: preserve baseUrl behavior with catch-all
+                "*": ["./src/*"]
+            }
+        }
+    }
+
+==== /after/src/app/module.ts (0 errors) ====
+    export const value = 42;
+
+==== /after/src/lib/utils.ts (0 errors) ====
+    export function helper() { return "help"; }
+
+==== /after/src/main.ts (0 errors) ====
+    import { value } from "@app/module";
+    import { helper } from "@lib/utils";
+    // With explicit catch-all mapping, this still works:
+    import * as something from "someModule"; // Resolves to ./src/someModule
+
+==== /after/src/someModule.ts (0 errors) ====
+    export const data = "from explicit path mapping";

tests/baselines/reference/baseUrlMigrationExample.js

@@ -0,0 +1,63 @@
+//// [tests/cases/compiler/baseUrlMigrationExample.ts] ////
+
+//// [tsconfig.json]
+{
+    "compilerOptions": {
+        "paths": {
+            // Explicit prefix for all path mappings
+            "@app/*": ["./src/app/*"],
+            "@lib/*": ["./src/lib/*"],
+            // Optional: preserve baseUrl behavior with catch-all
+            "*": ["./src/*"]
+        }
+    }
+}
+
+//// [module.ts]
+export const value = 42;
+
+//// [utils.ts]
+export function helper() { return "help"; }
+
+//// [main.ts]
+import { value } from "@app/module";
+import { helper } from "@lib/utils";
+// With explicit catch-all mapping, this still works:
+import * as something from "someModule"; // Resolves to ./src/someModule
+
+//// [someModule.ts]
+export const data = "from explicit path mapping";
+//// [module.ts]
+export const value = 42;
+
+//// [utils.ts]
+export function helper() { return "help"; }
+
+//// [main.ts]
+import { value } from "@app/module";
+import { helper } from "@lib/utils";
+// This would also resolve due to baseUrl:
+import * as something from "someModule"; // Resolves to ./src/someModule
+
+//// [someModule.ts]
+export const data = "from baseUrl resolution";
+
+
+//// [module.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.value = void 0;
+exports.value = 42;
+//// [utils.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.helper = helper;
+function helper() { return "help"; }
+//// [someModule.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.data = void 0;
+exports.data = "from baseUrl resolution";
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });

tests/baselines/reference/baseUrlMigrationExample.symbols

@@ -0,0 +1,25 @@
+//// [tests/cases/compiler/baseUrlMigrationExample.ts] ////
+
+=== /before/src/app/module.ts ===
+export const value = 42;
+>value : Symbol(value, Decl(module.ts, 0, 12))
+
+=== /before/src/lib/utils.ts ===
+export function helper() { return "help"; }
+>helper : Symbol(helper, Decl(utils.ts, 0, 0))
+
+=== /before/src/main.ts ===
+import { value } from "@app/module";
+>value : Symbol(value, Decl(main.ts, 0, 8))
+
+import { helper } from "@lib/utils";
+>helper : Symbol(helper, Decl(main.ts, 1, 8))
+
+// This would also resolve due to baseUrl:
+import * as something from "someModule"; // Resolves to ./src/someModule
+>something : Symbol(something, Decl(main.ts, 3, 6))
+
+=== /before/src/someModule.ts ===
+export const data = "from baseUrl resolution";
+>data : Symbol(data, Decl(someModule.ts, 0, 12))
+

tests/baselines/reference/baseUrlMigrationExample.types

@@ -0,0 +1,37 @@
+//// [tests/cases/compiler/baseUrlMigrationExample.ts] ////
+
+=== /before/src/app/module.ts ===
+export const value = 42;
+>value : 42
+>      : ^^
+>42 : 42
+>   : ^^
+
+=== /before/src/lib/utils.ts ===
+export function helper() { return "help"; }
+>helper : () => string
+>       : ^^^^^^^^^^^^
+>"help" : "help"
+>       : ^^^^^^
+
+=== /before/src/main.ts ===
+import { value } from "@app/module";
+>value : 42
+>      : ^^
+
+import { helper } from "@lib/utils";
+>helper : () => string
+>       : ^^^^^^^^^^^^
+
+// This would also resolve due to baseUrl:
+import * as something from "someModule"; // Resolves to ./src/someModule
+>something : typeof something
+>          : ^^^^^^^^^^^^^^^^
+
+=== /before/src/someModule.ts ===
+export const data = "from baseUrl resolution";
+>data : "from baseUrl resolution"
+>     : ^^^^^^^^^^^^^^^^^^^^^^^^^
+>"from baseUrl resolution" : "from baseUrl resolution"
+>                          : ^^^^^^^^^^^^^^^^^^^^^^^^^
+

tests/baselines/reference/deprecatedCompilerOptionsBaseUrl.errors.txt

@@ -0,0 +1,22 @@
+/foo/tsconfig.json(3,9): error TS5101: Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0. Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.
+
+
+==== /foo/tsconfig.json (1 errors) ====
+    {
+        "compilerOptions": {
+            "baseUrl": "./src",
+            ~~~~~~~~~
+!!! error TS5101: Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0. Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.
+            "paths": {
+                "@app/*": ["app/*"],
+                "@lib/*": ["lib/*"]
+            }
+        }
+    }
+
+==== /foo/src/app/module.ts (0 errors) ====
+    export const value = 42;
+
+==== /foo/src/main.ts (0 errors) ====
+    import { value } from "@app/module";
+    const result = value;

tests/baselines/reference/deprecatedCompilerOptionsBaseUrl.js

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/deprecatedCompilerOptionsBaseUrl.ts] ////
+
+//// [module.ts]
+export const value = 42;
+
+//// [main.ts]
+import { value } from "@app/module";
+const result = value;
+
+//// [module.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.value = void 0;
+exports.value = 42;
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+var module_1 = require("@app/module");
+var result = module_1.value;

tests/baselines/reference/deprecatedCompilerOptionsBaseUrl.symbols

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/deprecatedCompilerOptionsBaseUrl.ts] ////
+
+=== /foo/src/app/module.ts ===
+export const value = 42;
+>value : Symbol(value, Decl(module.ts, 0, 12))
+
+=== /foo/src/main.ts ===
+import { value } from "@app/module";
+>value : Symbol(value, Decl(main.ts, 0, 8))
+
+const result = value;
+>result : Symbol(result, Decl(main.ts, 1, 5))
+>value : Symbol(value, Decl(main.ts, 0, 8))
+

tests/baselines/reference/deprecatedCompilerOptionsBaseUrl.types

@@ -0,0 +1,20 @@
+//// [tests/cases/compiler/deprecatedCompilerOptionsBaseUrl.ts] ////
+
+=== /foo/src/app/module.ts ===
+export const value = 42;
+>value : 42
+>      : ^^
+>42 : 42
+>   : ^^
+
+=== /foo/src/main.ts ===
+import { value } from "@app/module";
+>value : 42
+>      : ^^
+
+const result = value;
+>result : 42
+>       : ^^
+>value : 42
+>      : ^^
+

tests/baselines/reference/deprecatedCompilerOptionsBaseUrlIgnored.js

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/deprecatedCompilerOptionsBaseUrlIgnored.ts] ////
+
+//// [module.ts]
+export const value = 42;
+
+//// [main.ts]
+import { value } from "@app/module";
+const result = value;
+
+//// [module.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.value = void 0;
+exports.value = 42;
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+var module_1 = require("@app/module");
+var result = module_1.value;

tests/baselines/reference/deprecatedCompilerOptionsBaseUrlIgnored.symbols

@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/deprecatedCompilerOptionsBaseUrlIgnored.ts] ////
+
+=== /foo/src/app/module.ts ===
+export const value = 42;
+>value : Symbol(value, Decl(module.ts, 0, 12))
+
+=== /foo/src/main.ts ===
+import { value } from "@app/module";
+>value : Symbol(value, Decl(main.ts, 0, 8))
+
+const result = value;
+>result : Symbol(result, Decl(main.ts, 1, 5))
+>value : Symbol(value, Decl(main.ts, 0, 8))
+

tests/baselines/reference/deprecatedCompilerOptionsBaseUrlIgnored.types

@@ -0,0 +1,20 @@
+//// [tests/cases/compiler/deprecatedCompilerOptionsBaseUrlIgnored.ts] ////
+
+=== /foo/src/app/module.ts ===
+export const value = 42;
+>value : 42
+>      : ^^
+>42 : 42
+>   : ^^
+
+=== /foo/src/main.ts ===
+import { value } from "@app/module";
+>value : 42
+>      : ^^
+
+const result = value;
+>result : 42
+>       : ^^
+>value : 42
+>      : ^^
+

tests/baselines/reference/pathMappingBasedModuleResolution4_classic.trace.json

@@ -1,8 +1,6 @@
 [
     "======== Resolving module 'folder2/file2' from 'c:/root/folder1/file1.ts'. ========",
     "Explicitly specified module resolution kind: 'Classic'.",
-    "'baseUrl' option is set to 'c:/root', using this value to resolve non-relative module name 'folder2/file2'.",
-    "Resolving module name 'folder2/file2' relative to base url 'c:/root' - 'c:/root/folder2/file2'.",
     "File 'c:/root/folder2/file2.ts' exists - use it as a name resolution result.",
     "======== Module name 'folder2/file2' was successfully resolved to 'c:/root/folder2/file2.ts'. ========",
     "======== Resolving module './file3' from 'c:/root/folder2/file2.ts'. ========",
@@ -11,11 +9,6 @@
     "======== Module name './file3' was successfully resolved to 'c:/root/folder2/file3.ts'. ========",
     "======== Resolving module 'file4' from 'c:/root/folder2/file2.ts'. ========",
     "Explicitly specified module resolution kind: 'Classic'.",
-    "'baseUrl' option is set to 'c:/root', using this value to resolve non-relative module name 'file4'.",
-    "Resolving module name 'file4' relative to base url 'c:/root' - 'c:/root/file4'.",
-    "File 'c:/root/file4.ts' does not exist.",
-    "File 'c:/root/file4.tsx' does not exist.",
-    "File 'c:/root/file4.d.ts' does not exist.",
     "File 'c:/root/folder2/file4.ts' does not exist.",
     "File 'c:/root/folder2/file4.tsx' does not exist.",
     "File 'c:/root/folder2/file4.d.ts' does not exist.",

tests/baselines/reference/pathMappingInheritedBaseUrl.js

@@ -3,7 +3,8 @@
 //// [tsconfig.base.json]
 {
   "compilerOptions": {
-    "baseUrl": "."
+    "baseUrl": ".",
+        "ignoreDeprecations": "6.0"
   }
 }
 

tests/baselines/reference/pathsValidation1.errors.txt

@@ -1,10 +1,11 @@
-tsconfig.json(5,18): error TS5063: Substitutions for pattern '*' should be an array.
+tsconfig.json(6,18): error TS5063: Substitutions for pattern '*' should be an array.
 
 
 ==== tsconfig.json (1 errors) ====
     {
         "compilerOptions": {
             "baseUrl": ".",
+            "ignoreDeprecations": "6.0",
             "paths": {
                 "*": "*"
                      ~~~