Swap out the complicated canary stuff for serial execution

Fixes #7386

README.md

@@ -256,6 +256,8 @@ First clone and build `matrix-js-sdk`:
 1. `git clone https://github.com/matrix-org/matrix-js-sdk.git`
 1. `pushd matrix-js-sdk`
 1. `git checkout develop`
+1. `npm install`
+1. `npm install source-map-loader`  # because webpack is made of fail (https://github.com/webpack/webpack/issues/1472)
 1. `popd`
 
 Then similarly with `matrix-react-sdk`:

package.json

@@ -36,22 +36,22 @@
     "build:bundle": "cross-env NODE_ENV=production webpack -p --progress --bail",
     "build:bundle:dev": "webpack --optimize-occurence-order --progress --bail",
     "build:electron": "npm run clean && npm run build && npm run install:electron && build -wml --ia32 --x64",
-    "build:react-sdk": "node scripts/build-watch-sdk.js build react",
-    "build:js-sdk": "node scripts//build-watch-sdk.js build js",
+    "build:react-sdk": "node scripts/npm-sub.js matrix-react-sdk run start:init",
+    "build:js-sdk": "node scripts/npm-sub.js matrix-js-sdk run start:init",
     "build": "npm run build:js-sdk && npm run build:react-sdk && npm run reskindex && npm run build:res && npm run build:bundle",
     "build:dev": "npm run build:js-sdk && npm run build:react-sdk && npm run reskindex && npm run build:res && npm run build:bundle:dev",
     "dist": "scripts/package.sh",
     "install:electron": "install-app-deps",
     "electron": "npm run install:electron && electron .",
     "start:res": "node scripts/copy-res.js -w",
-    "start:js": "node scripts/block-on-sdk-build.js js && node scripts/block-on-sdk-build.js react && webpack-dev-server --output-filename=bundles/_dev_/[name].js --output-chunk-file=bundles/_dev_/[name].js -w --progress",
-    "start:js:prod": "cross-env NODE_ENV=production node scripts/block-on-sdk-build.js js && node scripts/block-on-sdk-build.js react && webpack-dev-server -w --progress",
-    "start:js-sdk": "node scripts/build-watch-sdk.js watch js",
-    "start:js-sdk:prod": "cross-env NODE_ENV=production node && scripts/build-watch-sdk.js watch js",
-    "start:react-sdk": "node scripts/block-on-sdk-build.js js && node scripts/build-watch-sdk.js watch react",
-    "start:react-sdk:prod": "cross-env NODE_ENV=production node && scripts/block-on-sdk-build.js js && node scripts//build-watch-sdk.js watch react",
-    "start": "concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n js-sdk,react-sdk,reskindex,res,riot-js \"npm run start:js-sdk\" \"npm run start:react-sdk\" \"npm run reskindex:watch\" \"npm run start:res\" \"npm run start:js\"",
-    "start:prod": "concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n js-sdk,react-sdk,reskindex,res,riot-js \"npm run start:js-sdk:prod\" \"npm run start:react-sdk:prod\" \"npm run reskindex:watch\" \"npm run start:res\" \"npm run start:js:prod\"",
+    "start:js": "webpack-dev-server --output-filename=bundles/_dev_/[name].js --output-chunk-file=bundles/_dev_/[name].js -w --progress",
+    "start:js:prod": "cross-env NODE_ENV=production webpack-dev-server -w --progress",
+    "start:js-sdk": "node scripts/npm-sub.js matrix-js-sdk run start:watch",
+    "start:js-sdk:prod": "cross-env NODE_ENV=production node scripts/npm-sub.js matrix-js-sdk run start:watch",
+    "start:react-sdk": "node scripts/npm-sub.js matrix-react-sdk run start:all",
+    "start:react-sdk:prod": "cross-env NODE_ENV=production node scripts/npm-sub.js matrix-react-sdk run start:all",
+    "start": "npm run build:js-sdk && npm run build:react-sdk && concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n js-sdk,react-sdk,reskindex,res,riot-js \"npm run start:js-sdk\" \"npm run start:react-sdk\" \"npm run reskindex:watch\" \"npm run start:res\" \"npm run start:js\"",
+    "start:prod": "npm run build:js-sdk && npm run build:react-sdk && concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n js-sdk,react-sdk,reskindex,res,riot-js \"npm run start:js-sdk:prod\" \"npm run start:react-sdk:prod\" \"npm run reskindex:watch\" \"npm run start:res\" \"npm run start:js:prod\"",
     "lint": "eslint src/",
     "lintall": "eslint src/ test/",
     "clean": "rimraf lib webapp electron_app/dist",

scripts/npm-sub.js

@@ -0,0 +1,21 @@
+const path = require('path');
+const child_process = require('child_process');
+
+const moduleName = process.argv[2];
+if (!moduleName) {
+    console.error("Expected module name");
+    process.exit(1);
+}
+
+const argString = process.argv.length > 3 ? process.argv.slice(3).join(" ") : "";
+if (!argString) {
+    console.error("Expected an npm argument string to use");
+    process.exit(1);
+}
+
+const modulePath = path.dirname(require.resolve(`${moduleName}/package.json`));
+
+child_process.execSync("npm " + argString, {
+    env: process.env,
+    cwd: modulePath,
+});