From 026f4f9ae881d9196422981f1f85fa3137525014 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 19 Jun 2017 14:19:21 +0200
Subject: [PATCH] macOS: Remove flags

In particular, UF_IMMUTABLE (uchg) needs to be cleared to allow the
path to be garbage-collected or optimised.

See https://github.com/NixOS/nixpkgs/issues/25819.
+       the file from being garbage-collected.

(cherry picked from commit b5bdfdef7320d74a98af1e53d64371e0cef2dbbe)
---
 src/libstore/local-store.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 6888575f..d9ed4faf 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -571,6 +571,16 @@ static void canonicalisePathMetaData_(const Path & path, uid_t fromUid, InodesSe
 {
     checkInterrupt();
 
+#if __APPLE__
+    /* Remove flags, in particular UF_IMMUTABLE which would prevent
+       the file from being garbage-collected. FIXME: Use
+       setattrlist() to remove other attributes as well. */
+    if (lchflags(path.c_str(), 0)) {
+        if (errno != ENOTSUP)
+            throw SysError(format("clearing flags of path ‘%1%’") % path);
+    }
+#endif
+
     struct stat st;
     if (lstat(path.c_str(), &st))
         throw SysError(format("getting attributes of path ‘%1%’") % path);