build: add check for lib size

Gulpfile.js

@@ -12,6 +12,7 @@ const clone = require("gulp-clone");
 const newer = require("gulp-newer");
 const tsc = require("gulp-typescript");
 const tsc_oop = require("./scripts/build/gulp-typescript-oop");
+const { getDirSize } = require("./scripts/build/get-dir-size");
 const insert = require("gulp-insert");
 const sourcemaps = require("gulp-sourcemaps");
 const Q = require("q");
@@ -588,7 +589,14 @@ gulp.task("VerifyLKG", /*help*/ false, [], () => {
 gulp.task("LKGInternal", /*help*/ false, ["lib", "local"]);
 
 gulp.task("LKG", "Makes a new LKG out of the built js files", ["clean", "dontUseDebugMode"], () => {
-    return runSequence("LKGInternal", "VerifyLKG");
+    const lib = "./lib";
+    const sizeBefore = getDirSize(lib);
+    const seq = runSequence("LKGInternal", "VerifyLKG");
+    const sizeAfter = getDirSize(lib);
+    if (sizeAfter > (sizeBefore * 1.10)) {
+        throw new Error("The lib folder increased by 10% or more. This likely indicates a bug.");
+    }
+    return seq;
 });
 
 

scripts/build/get-dir-size.js

@@ -0,0 +1,32 @@
+// @ts-check
+const { lstatSync, readdirSync } = require("fs");
+const { join } = require("path");
+const { promisify } = require("util");
+const execFile = promisify(require("child_process").execFile);
+
+/**
+ * Find the size of a directory recursively.
+ * Symbolic links are counted once (same inode).
+ * @param {string} root
+ * @param {Set} seen
+ * @returns {number} bytes
+ */
+function getDirSize(root, seen = new Set()) {
+    const stats = lstatSync(root);
+
+    if (seen.has(stats.ino)) {
+        return 0;
+    }
+
+    seen.add(stats.ino);
+
+    if (!stats.isDirectory()) {
+        return stats.size;
+    }
+
+    return readdirSync(root)
+        .map(file => getDirSize(join(root, file), seen))
+        .reduce((acc, num) => acc + num, 0);
+}
+
+exports.getDirSize = getDirSize;