Merge pull request #8396 from blink1073/fix-watch-mode-1.2.x

[1.2.x] Fix watch mode and add CI Test

dev_mode/webpack.config.js

@@ -60,6 +60,32 @@ Object.keys(jlab.linkedPackages).forEach(function(name) {
   watched[name] = plib.dirname(localPkgPath);
 });
 
+/**
+ * Sync a local path to a linked package path if they are files and differ.
+ * This is used by `jupyter lab --watch` to synchronize linked packages
+ * and has no effect in `jupyter lab --dev-mode --watch`.
+ */
+function maybeSync(localPath, name, rest) {
+  const stats = fs.statSync(localPath);
+  if (!stats.isFile(localPath)) {
+    return;
+  }
+  const source = fs.realpathSync(plib.join(jlab.linkedPackages[name], rest));
+  if (source === fs.realpathSync(localPath)) {
+    return;
+  }
+  fs.watchFile(source, { interval: 500 }, function(curr) {
+    if (!curr || curr.nlink === 0) {
+      return;
+    }
+    try {
+      fs.copySync(source, localPath);
+    } catch (err) {
+      console.error(err);
+    }
+  });
+}
+
 /**
  * A filter function set up to exclude all files that are not
  * in a package contained by the Jupyterlab repo. Used to ignore
@@ -83,6 +109,7 @@ function ignored(path) {
     const rest = path.slice(rootPath.length);
     if (rest.indexOf('node_modules') === -1) {
       ignore = false;
+      maybeSync(path, name, rest);
     }
     return true;
   });

jupyterlab/browser_check.py

@@ -31,7 +31,10 @@
     {'BrowserApp': {'dev_mode': True}},
     "Start the app in dev mode."
 )
-
+test_flags['watch'] = (
+    {'BrowserApp': {'watch': True}},
+    "Start the app in watch mode."
+)
 
 test_aliases = dict(aliases)
 test_aliases['app-dir'] = 'BrowserApp.app_dir'

jupyterlab/extension.py

@@ -176,7 +176,7 @@ def load_jupyter_server_extension(nbapp):
             logger.info(DEV_NOTE)
 
     # Make sure the app dir exists.
-    else:
+    elif not watch_mode:
         msgs = ensure_app(app_dir)
         if msgs:
             [logger.error(msg) for msg in msgs]

scripts/ci_script.sh

@@ -221,6 +221,10 @@ if [[ $GROUP == usage ]]; then
     # Make sure the deprecated `selenium_check` command still works
     python -m jupyterlab.selenium_check
 
+    # Make sure we can run watch mode with no built application
+    jupyter lab clean
+    python -m jupyterlab.browser_check --watch
+
     # Make sure we can non-dev install.
     pip install virtualenv
     virtualenv -p $(which python3) test_install