prefer-export-from: Fix type-import being removed when using namespace import (#2771)

Author: k-yle

rules/prefer-export-from.js

@@ -86,14 +86,14 @@ function getFixFunction({
 		if (imported.name === NAMESPACE_SPECIFIER_NAME) {
 			yield fixer.insertTextAfter(
 				program,
-				`\nexport * as ${exported.text} ${getSourceAndAssertionsText(importDeclaration, context)}`,
+				`\nexport ${shouldExportAsType ? 'type ' : ''}* as ${exported.text} ${getSourceAndAssertionsText(importDeclaration, context)}`,
 			);
 		} else {
 			let specifierText = exported.name === imported.name
 				? exported.text
 				: `${imported.text} as ${exported.text}`;
 
-			// Add an inline type specifier if the value is a type and the export deceleration is a value deceleration
+			// Add an inline type specifier if the value is a type and the export declaration is a value declaration
 			if (shouldExportAsType && (!exportDeclaration || exportDeclaration.exportKind !== 'type')) {
 				specifierText = `type ${specifierText}`;
 			}
@@ -116,7 +116,8 @@ function getFixFunction({
 			}
 		}
 
-		if (imported.variable.references.length === 1) {
+		const importHasSideEffects = exported.isTypeExport && !imported.isTypeImport;
+		if (imported.variable.references.length === 1 && !importHasSideEffects) {
 			yield removeImportOrExport(imported.node, fixer, context);
 		}
 

test/prefer-export-from.js

@@ -474,6 +474,22 @@ test.snapshot({
 			export {foo};
 			export {bar} from './foo.json' assert { type: 'unknown' };
 		`,
+		outdent`
+			import type * as X from 'foo';
+			export { X };
+		`,
+		outdent`
+			import * as X from 'foo';
+			export type { X };
+		`,
+		outdent`
+			import type * as X from 'foo';
+			export type { X };
+		`,
+		outdent`
+			import * as X from 'foo';
+			export { X };
+		`,
 	],
 });
 

test/snapshots/prefer-export-from.js.md

@@ -1871,7 +1871,7 @@ Generated by [AVA](https://avajs.dev).
         |               ^^^ Use \`export…from\` to re-export \`foo\`.␊
     ␊
     Output:␊
-      1 |␊
+      1 | import { foo } from 'foo';␊
       2 |␊
       3 | export {type foo} from 'foo';␊
     `
@@ -2158,6 +2158,98 @@ Generated by [AVA](https://avajs.dev).
       3 | export {bar, foo} from './foo.json' assert { type: 'unknown' };␊
     `
 
+## invalid(26): import type * as X from 'foo'; export { X };
+
+> Input
+
+    `␊
+      1 | import type * as X from 'foo';␊
+      2 | export { X };␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+      1 | import type * as X from 'foo';␊
+    > 2 | export { X };␊
+        |          ^ Use \`export…from\` to re-export \`X\`.␊
+    ␊
+    Output:␊
+      1 |␊
+      2 |␊
+      3 | export type * as X from 'foo';␊
+    `
+
+## invalid(27): import * as X from 'foo'; export type { X };
+
+> Input
+
+    `␊
+      1 | import * as X from 'foo';␊
+      2 | export type { X };␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+      1 | import * as X from 'foo';␊
+    > 2 | export type { X };␊
+        |               ^ Use \`export…from\` to re-export \`X\`.␊
+    ␊
+    Output:␊
+      1 | import * as X from 'foo';␊
+      2 |␊
+      3 | export type * as X from 'foo';␊
+    `
+
+## invalid(28): import type * as X from 'foo'; export type { X };
+
+> Input
+
+    `␊
+      1 | import type * as X from 'foo';␊
+      2 | export type { X };␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+      1 | import type * as X from 'foo';␊
+    > 2 | export type { X };␊
+        |               ^ Use \`export…from\` to re-export \`X\`.␊
+    ␊
+    Output:␊
+      1 |␊
+      2 |␊
+      3 | export type * as X from 'foo';␊
+    `
+
+## invalid(29): import * as X from 'foo'; export { X };
+
+> Input
+
+    `␊
+      1 | import * as X from 'foo';␊
+      2 | export { X };␊
+    `
+
+> Error 1/1
+
+    `␊
+    Message:␊
+      1 | import * as X from 'foo';␊
+    > 2 | export { X };␊
+        |          ^ Use \`export…from\` to re-export \`X\`.␊
+    ␊
+    Output:␊
+      1 |␊
+      2 |␊
+      3 | export * as X from 'foo';␊
+    `
+
 ## invalid(1): import json from './foo.json' with { type: 'json' }; export default json;
 
 > Input