From c60bb394b6df7fddd33216f2a2ff2ea3da905a72 Mon Sep 17 00:00:00 2001
From: Ben Newman <ben@meteor.com>
Date: Fri, 19 Jan 2018 18:57:44 -0500
Subject: [PATCH] Go back to writing .meteor-portable-2.json files
 asynchronously.

This reverts commit 4e4e204ab0891ac5a8f90820955147e35a302d9c.

This commit caused a strange regression in reliability of the Windows
dynamic-import self-test, which may be an indication of a deeper problem,
so it seems safest to revert this change for now.

In case empty .meteor-portable-2.json files are written, I've added an
additional check that the cached JSON value is a boolean.
---
 tools/isobuild/meteor-npm.js | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/tools/isobuild/meteor-npm.js b/tools/isobuild/meteor-npm.js
index e0daed192f..a13a477754 100644
--- a/tools/isobuild/meteor-npm.js
+++ b/tools/isobuild/meteor-npm.js
@@ -496,7 +496,7 @@ const isPortable = Profile("meteorNpm.isPortable", dir => {
           allowSyntaxError: true
         });
 
-    if (result) {
+    if (typeof result === "boolean") {
       return result;
     }
 
@@ -528,17 +528,18 @@ const isPortable = Profile("meteorNpm.isPortable", dir => {
         isPortable(files.pathJoin(dir, itemName)));
 
   if (canCache) {
-    try {
-      files.writeFile(
-        portableFile,
-        JSON.stringify(result) + "\n",
-        "utf8"
-      );
-    } catch (ignored) {
-      // Don't worry if the write fails, e.g. because the file system is
-      // read-only (#6591). Failing to write the file only means more work
-      // next time.
-    }
+    // Write the .meteor-portable file asynchronously, and don't worry
+    // if it fails, e.g. because the file system is read-only (#6591).
+    // Failing to write the file only means more work next time.
+    fs.writeFile(
+      portableFile,
+      JSON.stringify(result) + "\n",
+      error => {
+        // Once the asynchronous write finishes (successful or not), we no
+        // longer need to cache the written value in memory.
+        delete portableCache[portableFile];
+      },
+    );
 
     // Cache the result immediately in memory so we don't have to wait for
     // file change notifications to invalidate optimisticReadJsonOrNull.