[new-rule] no-default-import (#4023)

* Implement 'no-default-import' rule

* Improve wording in rationale

src/configs/all.ts

@@ -157,6 +157,7 @@ export const rules = {
     "max-file-line-count": [true, 1000],
     "max-line-length": [true, 120],
     "no-default-export": true,
+    "no-default-import": true,
     "no-duplicate-imports": true,
     "no-irregular-whitespace": true,
     "no-mergeable-namespace": true,

src/rules/noDefaultImportRule.ts

@@ -0,0 +1,130 @@
+/**
+ * @license
+ * Copyright 2016 Palantir Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { isImportDeclaration, isNamedImports, isStringLiteral } from "tsutils";
+import * as ts from "typescript";
+import * as Lint from "../index";
+
+const fromModulesConfigOptionName = "fromModules";
+interface RawConfigOptions {
+    [fromModulesConfigOptionName]: string;
+}
+interface Options {
+    [fromModulesConfigOptionName]: RegExp;
+}
+
+export class Rule extends Lint.Rules.AbstractRule {
+    /* tslint:disable:object-literal-sort-keys */
+    public static metadata: Lint.IRuleMetadata = {
+        ruleName: "no-default-import",
+        description: "Disallows importing default members from certain ES6-style modules.",
+        descriptionDetails: "Import named members instead.",
+        rationale: Lint.Utils.dedent`
+            Named imports/exports [promote clarity](https://github.com/palantir/tslint/issues/1182#issue-151780453).
+            In addition, current tooling differs on the correct way to handle default imports/exports.
+            Avoiding them all together can help avoid tooling bugs and conflicts.
+
+            The rule supposed to narrow the scope of your changes in the case of monorepo.
+            Say, you have packages \`A\`, \`B\`, \`C\` and \`utils\`, where \`A\`, \`B\`, \`C\` dependends on \`utils\`,
+            which is full of default exports.
+            \`"no-default-export"\` requires you to remove default _export_ from \`utils\`, which leads to changes
+            in packages \`A\`, \`B\`, \`C\`. It's harder to get merged bigger changeset by various reasons (harder to get your code approved
+            due to a number of required reviewers; longer build time due to a number of affected packages)
+            and could result in ignored \`"no-default-export"\` rule in \`utils'\`.
+
+            Unlike \`"no-default-export"\`, the rule requires you to repalce default _import_ with named only in \`A\` you work on,
+            and \`utils\` you import from.`,
+        optionsDescription: "optionsDescription",
+        options: {
+            type: "array",
+            items: {
+                type: "object",
+                properties: {
+                    [fromModulesConfigOptionName]: { type: "string" },
+                },
+                required: [
+                    "fromModules",
+                ],
+            },
+        },
+        optionExamples: [
+            [true, { [fromModulesConfigOptionName]: "^palantir-|^_internal-*|^\\./|^\\.\\./" }],
+        ],
+        type: "maintainability",
+        typescriptOnly: false,
+    };
+    /* tslint:enable:object-literal-sort-keys */
+
+    public static FAILURE_STRING = "Import of default members from this module is forbidden. Import named member instead";
+
+    public static getNamedDefaultImport(namedBindings: ts.NamedImports): ts.Identifier | null {
+        for (const importSpecifier of namedBindings.elements) {
+            if (importSpecifier.propertyName !== undefined && importSpecifier.propertyName.text === "default") {
+                return importSpecifier.propertyName;
+            }
+        }
+        return null;
+    }
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithFunction(sourceFile, walk, this.getRuleOptions(this.ruleArguments));
+    }
+    private isFromModulesConfigOption(option: boolean | RawConfigOptions): option is RawConfigOptions {
+        return typeof option === "object" && option[fromModulesConfigOptionName] !== undefined;
+    }
+    private getRuleOptions(options: ReadonlyArray<boolean | RawConfigOptions>): Options {
+        const fromModuleConfigOption = options.find<RawConfigOptions>(this.isFromModulesConfigOption);
+        if (fromModuleConfigOption !== undefined && typeof fromModuleConfigOption[fromModulesConfigOptionName] === "string") {
+            return {
+                [fromModulesConfigOptionName]: new RegExp(fromModuleConfigOption[fromModulesConfigOptionName]),
+            };
+        } else {
+            return {
+                [fromModulesConfigOptionName]: new RegExp("^\\./|^\\.\\./"),
+            };
+        }
+    }
+}
+
+function walk(ctx: Lint.WalkContext<Options>) {
+    if (ctx.sourceFile.isDeclarationFile || !ts.isExternalModule(ctx.sourceFile)) {
+        return;
+    }
+    for (const statement of ctx.sourceFile.statements) {
+        if (isImportDeclaration(statement)) {
+            const { importClause, moduleSpecifier } = statement;
+            if (
+                importClause !== undefined
+                && isStringLiteral(moduleSpecifier)
+                && ctx.options[fromModulesConfigOptionName].test(moduleSpecifier.text)
+            ) {
+                // module name matches specified in rule config
+                if (importClause.name !== undefined) {
+                    // `import Foo...` syntax
+                    const defaultImportedName = importClause.name;
+                    ctx.addFailureAtNode(defaultImportedName, Rule.FAILURE_STRING);
+                } else if (importClause.namedBindings !== undefined && isNamedImports(importClause.namedBindings)) {
+                    // `import { default...` syntax
+                    const defaultMember = Rule.getNamedDefaultImport(importClause.namedBindings);
+                    if (defaultMember !== null) {
+                        ctx.addFailureAtNode(defaultMember, Rule.FAILURE_STRING);
+                    }
+                }
+            }
+        }
+    }
+}

test/rules/no-default-import/default/test.ts.lint

@@ -0,0 +1,36 @@
+import * as Utils from "tslint-utils"
+
+import TslintUtils from "tslint-utils"
+
+import Bar, { Foo } from "tslint-misc"
+
+import Bar, * as Foo from "tslint-misc"
+
+import { default as Foo } from "tslint-misc"
+
+import { default as foo, bar } from "tslint-misc"
+
+import { bar, default as foo } from "tslint-misc"
+
+import TslintUtils from "../tslint-utils"
+       ~~~~~~~~~~~ [0]
+
+import TslintUtils from "./tslint-utils"
+       ~~~~~~~~~~~ [0]
+
+import Bar, { Foo } from "../tslint-misc"
+       ~~~ [0]
+
+import Bar, * as Foo from "./tslint-misc"
+       ~~~ [0]
+
+import { default as Foo } from "../tslint-misc"
+         ~~~~~~~ [0]
+
+import { default as foo, bar } from "./tslint-misc"
+         ~~~~~~~ [0]
+
+import { bar, default as foo } from "../tslint-misc"
+              ~~~~~~~ [0]
+
+[0]: Import of default members from this module is forbidden. Import named member instead

test/rules/no-default-import/default/tslint.json

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "no-default-import": true
+  }
+}

test/rules/no-default-import/fromModules/test.ts.lint

@@ -0,0 +1,24 @@
+import * as Utils from "tslint-utils"
+
+import TslintUtils from "../tslint-utils"
+       ~~~~~~~~~~~ [0]
+
+import TslintUtils from "tslint-utils"
+       ~~~~~~~~~~~ [0]
+
+import Bar, { Foo } from "tslint-misc"
+       ~~~ [0]
+
+import Bar, * as Foo from "tslint-misc"
+       ~~~ [0]
+
+import { default as Foo } from "tslint-misc"
+         ~~~~~~~ [0]
+
+import { default as foo, bar } from "tslint-misc"
+         ~~~~~~~ [0]
+
+import { bar, default as foo } from "tslint-misc"
+              ~~~~~~~ [0]
+
+[0]: Import of default members from this module is forbidden. Import named member instead

test/rules/no-default-import/fromModules/tslint.json

@@ -0,0 +1,10 @@
+{
+  "rules": {
+    "no-default-import": [
+      true,
+      {
+        "fromModules": "^tslint-|^\\./|^\\.\\./"
+      }
+    ]
+  }
+}