remove main and package parsing

Author: guybedford

doc/api/esm.md

@@ -154,36 +154,6 @@ The resolver has the following properties:
 * No default extensions
 * No folder mains
 * Bare specifier package resolution lookup through node_modules
-* Avoids the package fallback which breaks package isolation. This is the
-  problem that an import to `x/y.js` will keep checking subsequent node_modules
-  even if a package "x" is found without a "y.js". This is done through package
-  name format detection.
-
-The ESM resolver differs from the CommonJS resolver in detecting a package name
-based on it being either `package` or `@scoped/package`. This allows the
-resolver to know when a package has been matched, and then avoid a fallback for
-missing modules.
-
-The main lookup is then provided by _CHECK_PACKAGE_MAIN_ which is still an
-experimental approach under discussion.
-
-Currently, the main lookup will only check for _index.mjs_.
-
-### Examples
-
-Relative and absolute resolution without directory or extension resolution
-(URL resolution):
-
-* ESM_RESOLVE("./a.asdf", "file:///parent/path") -> "file:///parent/a.asdf"
-* ESM_RESOLVE("/a", "file:///parent/path") -> "file:///a"
-* ESM_RESOLVE("file:///a", "file:///parent/path") -> "file:///a"
-
-Package resolution:
-
-1. ESM_RESOLVE("pkg/x", "file:///path/to/project") ->
-   "file:///path/to/nodemodules/pkg/x" (if it exists)
-1. ESM_RESOLVE("pkg/x", "file:///path/to/project") ->
-   Not Found otherwise, even if "file:///path/nodemodules/pkg/x" exists.
 
 ### Resolver Algorithm
 
@@ -207,50 +177,16 @@ _ESM_RESOLVE_:
 
 **PACKAGE_RESOLVE**(_packageSpecifier_, _parentURL_)
 > 1. Assert: _packageSpecifier_ is a bare specifier.
-> 1. Let _packageName_ be _undefined_.
-> 1. Let _packagePath_ be _undefined_.
-> 1. If _packageSpecifier_ does not start with _"@"_ then,
->    1. If _packageSpecifier_ is an empty string then,
->       1. Throw a _Invalid Package Name_ error.
->    1. Set _packageName_ to the substring of _packageSpecifier_ until the
->       first _"/"_ separator or the end of the string.
-> 1. If _packageSpecifier_ starts with _"@"_ then,
->    1. If _packageSpecifier_ does not contain a _"/"_ separator then,
->       1. Throw a _Invalid Package Name_ error.
->    1. Set _packageName_ to the substring of _packageSpecifier_
->       until the second _"/"_ separator or the end of the string.
-> 1. Let _packagePath_ be the substring of _packageSpecifier_ from the
->    position at the length of _packageName_ plus one, if any.
-> 1. Assert: _packageName_ is a valid package name or scoped package name.
-> 1. Assert: _packagePath_ is either empty, or a path without a leading
->    separator.
-> 1. Note: Further package name validations can be added here.
-> 1. If _packagePath_ is empty and _packageName_ is a Node.js builtin
->    module then,
+> 1. If _packageSpecifier_ is a Node.js builtin module then,
 >    1. Return _"node:${packageName}"_.
 > 1. Set _parentURL_ to the parent folder URL of _parentURL_.
 > 1. While _parentURL_ contains a non-empty _pathname_,
 >    1. Let _packageURL_ be the URL resolution of
->       _"${parentURL}/node_modules/${packageName}"_.
->    1. If the folder at _packageURL_ does not exist then,
->       1. Note: This check can be optimized out where possible in
->          implementation.
->       1. Set _parentURL_ to the parent URL path of _parentURL_.
->       1. Continue the next loop iteration.
->    1. If _packagePath_ is empty then,
->       1. Let _url_ be the result of **PACKAGE_MAIN_RESOLVE**(_packageURL_).
->       1. If _url_ is _undefined_ then,
->          1. Throw a _Module Not Found_ error.
->       1. Return _url_.
->    1. Otherwise,
->       1. Return the URL resolution of _packagePath_ in _packageURL_.
+>       _"${parentURL}/node_modules/${packageSpecifier}"_.
+>    1. If the file at _packageURL_ exists then,
+>       1. Return _packageURL_.
 > 1. Throw a _Module Not Found_ error.
 
-**PACKAGE_MAIN_RESOLVE**(_packageURL_)
-> 1. Note: Main resolution to be implemented here.
-> 1. Return _undefined_.
-
-
 [Node.js EP for ES Modules]: https://github.com/nodejs/node-eps/blob/master/002-es-modules.md
 [`module.createRequireFromPath()`]: modules.html#modules_module_createrequirefrompath_filename
 [ESM Minimal Kernel]: https://github.com/nodejs/modules/blob/master/doc/plan-for-new-modules-implementation.md

src/module_wrap.cc

@@ -485,60 +485,15 @@ DescriptorType CheckDescriptor(const std::string& path) {
   return NONE;
 }
 
-inline Maybe<URL> PackageMainResolve(const URL& search) {
-  return Nothing<URL>();
-}
-
 Maybe<URL> PackageResolve(Environment* env,
                           const std::string& specifier,
                           const URL& base) {
-  size_t sep_index = specifier.find('/');
-  if (specifier[0] == '@' && sep_index == std::string::npos ||
-      specifier.length() == 0) {
-    std::string msg = "Invalid package name '" + specifier +
-      "' imported from " + base.ToFilePath();
-    node::THROW_ERR_INVALID_PACKAGE_NAME(env, msg.c_str());
-    return Nothing<URL>();
-  }
-  if (specifier[0] == '@') {
-    sep_index = specifier.find('/', sep_index + 1);
-  }
-  std::string pkg_name = specifier.substr(0,
-      sep_index == std::string::npos ? std::string::npos : sep_index);
-  std::string pkg_path;
-  if (sep_index == std::string::npos ||
-      sep_index == specifier.length() - 1) {
-    pkg_path = "";
-  } else {
-    pkg_path = specifier.substr(sep_index);
-  }
   URL parent(".", base);
   std::string last_path;
   do {
-    URL pkg_url("./node_modules/" + pkg_name, &parent);
-    URL url;
-    if (pkg_path.length()) {
-      url = URL("./node_modules/" + pkg_name + pkg_path, &parent);
-    } else {
-      url = pkg_url;
-    }
-    DescriptorType check;
-    if (pkg_path.length()) {
-      DescriptorType check = CheckDescriptor(url.ToFilePath());
-      if (check == FILE) return Just(url);
-      if (check == NONE) check = CheckDescriptor(pkg_url.ToFilePath());
-    } else {
-      Maybe<URL> main_url = PackageMainResolve(url);
-      if (!main_url.IsNothing()) return main_url;
-      check = CheckDescriptor(pkg_url.ToFilePath());
-    }
-    // throw not found if we did match a package directory
-    if (check == DIRECTORY) {
-      std::string msg = "Cannot find module '" + url.ToFilePath() +
-          "' imported from " + base.ToFilePath();
-      node::THROW_ERR_MODULE_NOT_FOUND(env, msg.c_str());
-      return Nothing<URL>();
-    }
+    URL pkg_url("./node_modules/" + specifier, &parent);
+    DescriptorType check = CheckDescriptor(pkg_url.ToFilePath());
+    if (check == FILE) return Just(pkg_url);
     last_path = parent.path();
     parent = URL("..", &parent);
     // cross-platform root check