Merge pull request #136 from rth/load-packages-multiple

Load multiple packages in pyodide.loadPackage

docs/using_pyodide_from_iodide.md

@@ -61,6 +61,11 @@ When you request a package from the official repository, all of that package's
 dependencies are also loaded. Dependency resolution is not yet implemented
 when loading packages from custom URLs.
 
+Multiple packages can also be loaded in a single call,
+```js
+pyodide.loadPackage(['cycler', 'pytz'])
+```
+
 `pyodide.loadPackage` returns a `Promise`.
 
 ```javascript

docs/using_pyodide_from_javascript.md

@@ -49,6 +49,11 @@ When you request a package from the official repository, all of that package's
 dependencies are also loaded. Dependency resolution is not yet implemented
 when loading packages from custom URLs.
 
+Multiple packages can also be loaded in a single call,
+```js
+pyodide.loadPackage(['cycler', 'pytz'])
+```
+
 `pyodide.loadPackage` returns a `Promise`.
 
 ```javascript

src/pyodide.js

@@ -36,7 +36,7 @@ var languagePluginLoader = new Promise((resolve, reject) => {
   let loadPackage = (names) => {
     // DFS to find all dependencies of the requested packages
     let packages = window.pyodide.packages.dependencies;
-    let queue = new Array(names);
+    let queue = [].concat(names || []);
     let toLoad = new Array();
     while (queue.length) {
       let package_uri = queue.pop();
@@ -49,8 +49,6 @@ var languagePluginLoader = new Promise((resolve, reject) => {
         package_uri = 'default channel';
       }
 
-      console.log(`Loading ${package} from ${package_uri}`);
-
       if (package in loadedPackages) {
         if (package_uri != loadedPackages[package]) {
           throw new Error(
@@ -58,7 +56,16 @@ var languagePluginLoader = new Promise((resolve, reject) => {
               `${package} from ${package_uri} while it is already ` +
               `loaded from ${loadedPackages[package]}!`);
         }
+      } else if (package in toLoad) {
+        if (package_uri != toLoad[package]) {
+          throw new Error(
+              `URI mismatch, attempting to load package ` +
+              `${package} from ${package_uri} while it is already ` +
+              `being loaded from ${toLoad[package]}!`);
+        }
       } else {
+        console.log(`Loading ${package} from ${package_uri}`);
+
         toLoad[package] = package_uri;
         if (packages.hasOwnProperty(package)) {
           packages[package].forEach((subpackage) => {

test/test_package_loading.py

@@ -34,3 +34,18 @@ def test_invalid_package_name(selenium):
     with pytest.raises(WebDriverException,
                        match="Invalid package name or URI"):
         selenium.load_package('tcp://some_url')
+
+
+@pytest.mark.parametrize('packages', [['pyparsing', 'pytz'],
+                                      ['pyparsing', 'matplotlib']],
+                         ids='-'.join)
+def test_load_packages_multiple(selenium_standalone, packages):
+    selenium = selenium_standalone
+    selenium.load_package(packages)
+    selenium.run(f'import {packages[0]}')
+    selenium.run(f'import {packages[1]}')
+    # The long must show that each package is loaded exactly once,
+    # including when one package is a dependency of the other
+    # ('pyparsing' and 'matplotlib')
+    assert selenium.logs.count(f'Loading {packages[0]}') == 1
+    assert selenium.logs.count(f'Loading {packages[1]}') == 1