From b3d5220da5c62a709bab0e350ebc9f4ce1be0e83 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Mon, 31 Aug 2020 10:52:54 +0930
Subject: [PATCH] tools/refresh-submodules.sh: don't exit, but wait if called
 in parallel.

Otherwise make thinks we're done, and we can get errors.  Include
primitive code if we abort build halfway and leave .refresh-submodules dir.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 tools/refresh-submodules.sh | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/refresh-submodules.sh b/tools/refresh-submodules.sh
index 1f5964666..d78590217 100755
--- a/tools/refresh-submodules.sh
+++ b/tools/refresh-submodules.sh
@@ -9,8 +9,18 @@ fi
 [ -d .git ] || exit 0
 
 # git submodule can't run in parallel.  Really.
+# Wait for it to finish if in parallel.
 if ! mkdir .refresh-submodules 2>/dev/null ; then
-    exit 0
+    # If we don't make progress in ~60 seconds, force delete and retry.
+    LIMIT=$((50 + $$ % 20))
+    i=0
+    while [ $i -lt $LIMIT ]; do
+	[ -d .refresh-submodules ] || exit 0
+	sleep 1
+	i=$((i + 1))
+    done
+    rmdir .refresh-submodules
+    exec "$0" "$@" || exit 1
 fi
 
 trap "rmdir .refresh-submodules" EXIT