fixup resolution bugs

lib/internal/modules/cjs/loader.js

@@ -85,7 +85,8 @@ const manifest = getOptionValue('--experimental-policy') ?
   require('internal/process/policy').manifest :
   null;
 const { compileFunction } = internalBinding('contextify');
-const userConditions = (getOptionValue('--conditions') || '').split(',');
+const userConditions = getOptionValue('--conditions') &&
+    getOptionValue('--conditions').split(',');
 
 // Whether any user-provided CJS modules had been loaded (executed).
 // Used for internal assertions.
@@ -498,8 +499,12 @@ function applyExports(basePath, expansion) {
   if (typeof pkgExports === 'object') {
     if (ObjectPrototypeHasOwnProperty(pkgExports, mappingKey)) {
       const mapping = pkgExports[mappingKey];
-      return resolveExportsTarget(pathToFileURL(basePath + '/'), mapping, '',
-                                  mappingKey);
+      const resolved = resolveExportsTarget(
+        pathToFileURL(basePath + '/'), mapping, '', mappingKey);
+      if (resolved === null || resolved === undefined)
+        throw new ERR_PACKAGE_PATH_NOT_EXPORTED(
+          basePath, mappingKey);
+      return resolved;
     }
 
     let dirMatch = '';
@@ -516,6 +521,9 @@ function applyExports(basePath, expansion) {
       const subpath = StringPrototypeSlice(mappingKey, dirMatch.length);
       const resolved = resolveExportsTarget(pathToFileURL(basePath + '/'),
                                             mapping, subpath, mappingKey);
+      if (resolved === null || resolved === undefined)
+        throw new ERR_PACKAGE_PATH_NOT_EXPORTED(
+          basePath, mappingKey + subpath);
       // Extension searching for folder exports only
       const rc = stat(resolved);
       if (rc === 0) return resolved;
@@ -603,21 +611,29 @@ function resolveExportsTarget(baseUrl, target, subpath, mappingKey) {
     throw new ERR_INVALID_MODULE_SPECIFIER(mappingKey + subpath, reason);
   } else if (ArrayIsArray(target)) {
     if (target.length === 0)
-      throw new ERR_PACKAGE_PATH_NOT_EXPORTED(
-        baseUrl.pathname, mappingKey + subpath);
+      return null;
     let lastException;
     for (const targetValue of target) {
+      let resolved;
       try {
-        return resolveExportsTarget(baseUrl, targetValue, subpath, mappingKey);
+        resolved = resolveExportsTarget(baseUrl, targetValue, subpath,
+                                        mappingKey);
       } catch (e) {
         lastException = e;
-        if (e.code !== 'ERR_PACKAGE_PATH_NOT_EXPORTED' &&
-            e.code !== 'ERR_INVALID_PACKAGE_TARGET')
+        if (e.code !== 'ERR_INVALID_PACKAGE_TARGET')
           throw e;
       }
+      if (resolved === undefined)
+        continue;
+      if (resolved === null) {
+        lastException = null;
+        continue;
+      }
+      return resolved;
     }
     // Throw last fallback error
-    assert(lastException !== undefined);
+    if (lastException === undefined || lastException === null)
+      return lastException;
     throw lastException;
   } else if (typeof target === 'object' && target !== null) {
     const keys = ObjectKeys(target);
@@ -627,20 +643,16 @@ function resolveExportsTarget(baseUrl, target, subpath, mappingKey) {
     }
     for (const p of keys) {
       if (cjsConditions.has(p) || p === 'default') {
-        try {
-          return resolveExportsTarget(baseUrl, target[p], subpath,
-                                      mappingKey);
-        } catch (e) {
-          if (e.code !== 'ERR_PACKAGE_PATH_NOT_EXPORTED') throw e;
-        }
-        break;
+        const resolved = resolveExportsTarget(baseUrl, target[p], subpath,
+                                              mappingKey);
+        if (resolved === undefined)
+          continue;
+        return resolved;
       }
     }
-    throw new ERR_PACKAGE_PATH_NOT_EXPORTED(
-      baseUrl.pathname, mappingKey + subpath);
+    return undefined;
   } else if (target === null) {
-    throw new ERR_PACKAGE_PATH_NOT_EXPORTED(
-      baseUrl.pathname, mappingKey + subpath);
+    return null;
   }
   throw new ERR_INVALID_PACKAGE_TARGET(baseUrl.pathname, mappingKey, target);
 }

lib/internal/modules/esm/resolve.js

@@ -51,7 +51,8 @@ const {
 const { Module: CJSModule } = require('internal/modules/cjs/loader');
 
 const packageJsonReader = require('internal/modules/package_json_reader');
-const userConditions = (getOptionValue('--conditions') || '').split(',');
+const userConditions = getOptionValue('--conditions') &&
+    getOptionValue('--conditions').split(',');
 const DEFAULT_CONDITIONS = ObjectFreeze(['node', 'import', ...userConditions]);
 const DEFAULT_CONDITIONS_SET = new SafeSet(DEFAULT_CONDITIONS);
 
@@ -360,12 +361,9 @@ function isArrayIndex(key) {
 function resolvePackageTarget(
   packageJSONUrl, target, subpath, packageSubpath, base, internal, conditions) {
   if (typeof target === 'string') {
-    const resolved = resolvePackageTargetString(
+    return finalizeResolution(resolvePackageTargetString(
       target, subpath, packageSubpath, packageJSONUrl, base, internal,
-      conditions);
-    if (resolved === null)
-      return null;
-    return finalizeResolution(resolved, base);
+      conditions), base);
   } else if (ArrayIsArray(target)) {
     if (target.length === 0)
       return null;