Fix exported identifier refs for re-exports (fixes #622)

packages/knip/fixtures/exports-in-file-allowed-re-export/component.ts

@@ -0,0 +1,7 @@
+import type { ComponentProps } from './interface';
+
+export type { ComponentProps };
+
+export default function Wrapper(props: ComponentProps) {
+  return props;
+}

packages/knip/fixtures/exports-in-file-allowed-re-export/index.ts

@@ -0,0 +1,3 @@
+import Component from './component';
+
+Component;

packages/knip/fixtures/exports-in-file-allowed-re-export/interface.ts

@@ -0,0 +1,3 @@
+export interface ComponentProps {
+  n: number;
+}

packages/knip/fixtures/exports-in-file-allowed-re-export/knip.json

@@ -0,0 +1,3 @@
+{
+  "ignoreExportsUsedInFile": true
+}

packages/knip/fixtures/exports-in-file-allowed-re-export/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "@fixtures/exports-in-file-allowed-re-export"
+}

packages/knip/src/typescript/getImportsAndExports.ts

@@ -357,15 +357,31 @@ const getImportsAndExports = (
 
   const setRefs = (item: SerializableExport | SerializableExportMember) => {
     if (!item.symbol) return;
+    const symbols = new Set<ts.Symbol>();
     for (const match of sourceFile.text.matchAll(new RegExp(item.identifier.replace(/\$/g, '\\$'), 'g'))) {
       const isDeclaration = match.index === item.pos || match.index === item.pos + 1; // off-by-one from `stripQuotes`
       if (!isDeclaration) {
         // @ts-expect-error ts.getTokenAtPosition is internal fn
-        const smbl = typeChecker.getSymbolAtLocation(ts.getTokenAtPosition(sourceFile, match.index));
-        // @ts-expect-error Keep it cheap
-        if (smbl && (item.symbol === smbl || item.symbol === smbl.declarations?.[0]?.name?.flowNode?.node?.symbol)) {
-          item.refs = 1;
-          break;
+        const symbol = typeChecker.getSymbolAtLocation(ts.getTokenAtPosition(sourceFile, match.index));
+        if (symbol) {
+          if (item.symbol === symbol) {
+            item.refs = 1;
+            break;
+          }
+          // @ts-expect-error Keep it cheap
+          const declaration = symbol.declarations?.[0];
+          if (declaration) {
+            if (item.symbol === declaration.name?.flowNode?.node?.symbol) {
+              item.refs = 1;
+              break;
+            }
+            if (ts.isImportSpecifier(declaration) && symbols.has(symbol)) {
+              // re-exported symbol is referenced
+              item.refs = 1;
+              break;
+            }
+          }
+          symbols.add(symbol);
         }
       }
     }

packages/knip/test/exports-in-file-allowed-re-export.test.ts

@@ -0,0 +1,21 @@
+import { test } from 'bun:test';
+import assert from 'node:assert/strict';
+import { main } from '../src/index.js';
+import { resolve } from '../src/util/path.js';
+import baseArguments from './helpers/baseArguments.js';
+import baseCounters from './helpers/baseCounters.js';
+
+const cwd = resolve('fixtures/exports-in-file-allowed-re-export');
+
+test('Find unused exports respecting an ignoreExportsUsedInFile (re-export)', async () => {
+  const { counters } = await main({
+    ...baseArguments,
+    cwd,
+  });
+
+  assert.deepEqual(counters, {
+    ...baseCounters,
+    processed: 3,
+    total: 3,
+  });
+});