eslint: add plugin to warn against src imports

configs/errors.eslintrc.json

@@ -130,6 +130,7 @@
         }
       }
     ],
+    "@theia/no-src-import": "error",
     "@theia/runtime-import-check": "error",
     "@theia/shared-dependencies": "error",
     "import/no-extraneous-dependencies": "error",

dev-packages/eslint-plugin/README.md

@@ -17,6 +17,11 @@ The plugin helps identify problems during development through static analysis in
 
 ## Rules
 
+### `no-src-import`:
+
+The rule prevents imports using `/src/` rather than `/lib/` as it causes build failures.
+The rule helps developers more easily identify the cause of build errors caused by the incorrect import.
+
 #### `runtime-import-check`:
 
 The rule prevents imports from folders meant for incompatible runtimes.

dev-packages/eslint-plugin/index.js

@@ -17,6 +17,7 @@
 
 /** @type {{[ruleId: string]: import('eslint').Rule.RuleModule}} */
 exports.rules = {
+    "no-src-import": require('./rules/no-src-import'),
     "runtime-import-check": require('./rules/runtime-import-check'),
     "shared-dependencies": require('./rules/shared-dependencies')
 };

dev-packages/eslint-plugin/rules/no-src-import.js

@@ -0,0 +1,54 @@
+// @ts-check
+/********************************************************************************
+ * Copyright (C) 2021 Ericsson and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+const path = require('path');
+
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+    meta: {
+        type: 'problem',
+        fixable: 'code',
+        docs: {
+            description: 'prevent imports from \'src\'.',
+        },
+    },
+    create(context) {
+        return {
+            ImportDeclaration(node) {
+                checkModuleImport(node.source);
+            },
+            TSExternalModuleReference(node) {
+                checkModuleImport(node.expression);
+            },
+        };
+        function checkModuleImport(node) {
+            const module = /** @type {string} */(node.value);
+            const extension = path.parse(module).ext;
+            const re = /^@theia\/\S+\/src\//;
+            if (re.test(module) && extension === '') {
+                context.report({
+                    node,
+                    message: `'${module}' should not be imported with '/src/'`,
+                    fix: function (fixer) {
+                        const updatedModule = `'${module.replace('/src/', '/lib/')}'`;
+                        return fixer.replaceText(node, updatedModule);
+                    }
+                });
+            }
+        }
+    }
+};