From 0e2ebd5e376bb1e8ca6dd9256742cb0df1da9d27 Mon Sep 17 00:00:00 2001
From: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com>
Date: Wed, 13 Apr 2022 03:52:39 +0200
Subject: [PATCH] getSymbolResolution: fallback to asset's symbol with
 non-static dependencies (#7944)

---
 packages/core/core/src/BundleGraph.js         | 31 ++++++++++++++-----
 .../formats/esm-filename-import/index.js      |  3 ++
 .../formats/esm-filename-import/package.json  |  8 +++++
 .../formats/esm-filename-import/yarn.lock     |  0
 .../integration-tests/test/output-formats.js  | 11 +++++++
 5 files changed, 46 insertions(+), 7 deletions(-)
 create mode 100644 packages/core/integration-tests/test/integration/formats/esm-filename-import/index.js
 create mode 100644 packages/core/integration-tests/test/integration/formats/esm-filename-import/package.json
 create mode 100644 packages/core/integration-tests/test/integration/formats/esm-filename-import/yarn.lock

diff --git a/packages/core/core/src/BundleGraph.js b/packages/core/core/src/BundleGraph.js
index 3f0de396c84..4ee291557fd 100644
--- a/packages/core/core/src/BundleGraph.js
+++ b/packages/core/core/src/BundleGraph.js
@@ -1398,13 +1398,14 @@ export default class BundleGraph {
     }
 
     let found = false;
+    let nonStaticDependency = false;
     let skipped = false;
     let deps = this.getDependencies(asset).reverse();
     let potentialResults = [];
     for (let dep of deps) {
       let depSymbols = dep.symbols;
       if (!depSymbols) {
-        found = true;
+        nonStaticDependency = true;
         continue;
       }
       // If this is a re-export, find the original module.
@@ -1523,15 +1524,31 @@ export default class BundleGraph {
       // ..., but if it does exist, it has to be behind this one reexport.
       return potentialResults[0];
     } else {
-      // ... and there is no single reexport, but `bailout` tells us if it might still be exported.
+      let result = identifier;
+      if (skipped) {
+        // ... and it was excluded (by symbol propagation) or deferred.
+        result = false;
+      } else {
+        // ... and there is no single reexport, but it might still be exported:
+        if (found) {
+          // Fallback to namespace access, because of a bundle boundary.
+          result = null;
+        } else if (result === undefined) {
+          // If not exported explicitly by the asset (= would have to be in * or a reexport-all) ...
+          if (nonStaticDependency || asset.symbols?.has('*')) {
+            // ... and if there are non-statically analyzable dependencies or it's a CJS asset,
+            // fallback to namespace access.
+            result = null;
+          }
+          // (It shouldn't be possible for the symbol to be in a reexport-all and to end up here).
+          // Otherwise return undefined to report that the symbol wasn't found.
+        }
+      }
+
       return {
         asset,
         exportSymbol: symbol,
-        symbol: skipped
-          ? false
-          : found
-          ? null
-          : identifier ?? (asset.symbols?.has('*') ? null : undefined),
+        symbol: result,
         loc: asset.symbols?.get(symbol)?.loc,
       };
     }
diff --git a/packages/core/integration-tests/test/integration/formats/esm-filename-import/index.js b/packages/core/integration-tests/test/integration/formats/esm-filename-import/index.js
new file mode 100644
index 00000000000..b58a6e7c90b
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/formats/esm-filename-import/index.js
@@ -0,0 +1,3 @@
+import path from "path";
+
+export const foo = __filename;
diff --git a/packages/core/integration-tests/test/integration/formats/esm-filename-import/package.json b/packages/core/integration-tests/test/integration/formats/esm-filename-import/package.json
new file mode 100644
index 00000000000..b02e8668a8e
--- /dev/null
+++ b/packages/core/integration-tests/test/integration/formats/esm-filename-import/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "esm-filename-import",
+  "private": true,
+  "main": "dist/index.js",
+  "engines": {
+    "node": ">=10"
+  }
+}
diff --git a/packages/core/integration-tests/test/integration/formats/esm-filename-import/yarn.lock b/packages/core/integration-tests/test/integration/formats/esm-filename-import/yarn.lock
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/packages/core/integration-tests/test/output-formats.js b/packages/core/integration-tests/test/output-formats.js
index 834dc7a56f0..7b71ef26b90 100644
--- a/packages/core/integration-tests/test/output-formats.js
+++ b/packages/core/integration-tests/test/output-formats.js
@@ -1206,6 +1206,17 @@ describe('output formats', function () {
       assert.deepEqual({...ns}, {default: {default: 'default'}});
     });
 
+    it('should support rewriting filename and importing path', async function () {
+      let input = path.join(
+        __dirname,
+        '/integration/formats/esm-filename-import/index.js',
+      );
+      let b = await bundle(input);
+
+      let ns = await run(b);
+      assert.deepEqual(ns.foo, input);
+    });
+
     it('should rename shadowed imported specifiers to something unique', async function () {
       let b = await bundle(
         path.join(__dirname, '/integration/formats/esm-import-shadow/a.mjs'),