Fix accidental relative imports from non namespace barrels (#59544)

scripts/eslint/rules/no-direct-import.cjs

@@ -0,0 +1,81 @@
+const { createRule } = require("./utils.cjs");
+const path = require("path");
+
+/** @import { TSESTree } from "@typescript-eslint/utils" */
+void 0;
+
+module.exports = createRule({
+    name: "no-direct-import",
+    meta: {
+        docs: {
+            description: ``,
+        },
+        messages: {
+            noDirectImport: `This import relatively references another project; did you mean to import from a local _namespace module?`,
+        },
+        schema: [],
+        type: "problem",
+    },
+    defaultOptions: [],
+
+    create(context) {
+        const containingFileName = context.filename;
+        const containingDirectory = path.dirname(containingFileName);
+
+        /** @type {(node: TSESTree.ImportDeclaration | TSESTree.TSImportEqualsDeclaration) => void} */
+        const check = node => {
+            let source;
+            if (node.type === "TSImportEqualsDeclaration") {
+                const moduleReference = node.moduleReference;
+                if (
+                    moduleReference.type === "TSExternalModuleReference"
+                    && moduleReference.expression.type === "Literal"
+                    && typeof moduleReference.expression.value === "string"
+                ) {
+                    source = moduleReference.expression;
+                }
+            }
+            else {
+                source = node.source;
+            }
+
+            if (!source) return;
+
+            const p = source.value;
+
+            // These appear in place of public API imports.
+            if (p.endsWith("../typescript/typescript.js")) return;
+
+            // The below is similar to https://github.com/microsoft/DefinitelyTyped-tools/blob/main/packages/eslint-plugin/src/rules/no-bad-reference.ts
+
+            // Any relative path that goes to the wrong place will contain "..".
+            if (!p.includes("..")) return;
+
+            const parts = p.split("/");
+            let cwd = containingDirectory;
+            for (const part of parts) {
+                if (part === "" || part === ".") {
+                    continue;
+                }
+                if (part === "..") {
+                    cwd = path.dirname(cwd);
+                }
+                else {
+                    cwd = path.join(cwd, part);
+                }
+
+                if (path.basename(cwd) === "src") {
+                    context.report({
+                        messageId: "noDirectImport",
+                        node: source,
+                    });
+                }
+            }
+        };
+
+        return {
+            ImportDeclaration: check,
+            TSImportEqualsDeclaration: check,
+        };
+    },
+});