From 57126a7973442230c64147023e5130f7cecf9d8d Mon Sep 17 00:00:00 2001
From: Codinget <nathan.decher@gmail.com>
Date: Sun, 10 Jan 2021 22:19:10 +0100
Subject: [PATCH] fixed mkdirs sometimes failing due to race condition when
 multiprocess builds are running

---
 moonbuild/_fs.moon | 12 +++++++++---
 out/moonbuild.lua  | 25 +++++++++++++++++++------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/moonbuild/_fs.moon b/moonbuild/_fs.moon
index 386508d..f494d11 100644
--- a/moonbuild/_fs.moon
+++ b/moonbuild/_fs.moon
@@ -166,10 +166,16 @@ mkdir = (dir) ->
 	clearentry parent dir
 
 mkdirs = (dir) ->
-	return if isdir dir
-	error "Can't mkdirs #{dir}: file exists" if exists dir
+	if attr = attributes normalizepath dir
+		return if attr.mode == 'directory'
+		error "Can't mkdirs #{dir}: file exists"
 	mkdirs parent dir
-	mkdir dir
+	unless pcall -> actualmkdir dir
+		clearentry parent dir
+		clearentry dir
+		error "Failed to mkdirs #{dir}: last mkdir failed" unless isdir dir
+	clearentry parent dir
+	clearentry dir
 
 -- from the backend
 fs = {k, withcache fn for k, fn in pairs fs}
diff --git a/out/moonbuild.lua b/out/moonbuild.lua
index 483bc99..e9bd49f 100644
--- a/out/moonbuild.lua
+++ b/out/moonbuild.lua
@@ -973,14 +973,27 @@ mkdir = function(dir)
 end
 local mkdirs
 mkdirs = function(dir)
-  if isdir(dir) then
-    return 
-  end
-  if exists(dir) then
-    error("Can't mkdirs " .. tostring(dir) .. ": file exists")
+  do
+    local attr = attributes(normalizepath(dir))
+    if attr then
+      if attr.mode == 'directory' then
+        return 
+      end
+      error("Can't mkdirs " .. tostring(dir) .. ": file exists")
+    end
   end
   mkdirs(parent(dir))
-  return mkdir(dir)
+  if not (pcall(function()
+    return actualmkdir(dir)
+  end)) then
+    clearentry(parent(dir))
+    clearentry(dir)
+    if not (isdir(dir)) then
+      error("Failed to mkdirs " .. tostring(dir) .. ": last mkdir failed")
+    end
+  end
+  clearentry(parent(dir))
+  return clearentry(dir)
 end
 do
   local _tbl_0 = { }