From 17e45badd95b059b6375a3206a75d2354879a2cf Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Tue, 9 Aug 2016 02:50:57 +0200
Subject: [PATCH] update/patch: avoid applying patches directly in build repos

Switching branches and applying patches in the build repos will
unnecessarily touch many files, causing rebuilds of packages that didn't
really change; furthermore, it is filling the reflog with many entries.

Don't ever switch to base branch in the build repos and apply patches in
a temporary clone to avoid these issues.

In addition, GPG signing is generally disabled in the build repos to
override potential global configuration (as signing doesn't make sense and
will slow down rebases).
---
 scripts/patch.sh  | 26 +++++++++++++++++---------
 scripts/update.sh |  5 ++---
 2 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/scripts/patch.sh b/scripts/patch.sh
index 90d2de7b..2b0aa29e 100755
--- a/scripts/patch.sh
+++ b/scripts/patch.sh
@@ -5,19 +5,27 @@ shopt -s nullglob
 
 . "$GLUONDIR"/scripts/modules.sh
 
+TMPDIR="$GLUON_BUILDDIR"/tmp
+
+mkdir -p "$TMPDIR"
+
+PATCHDIR="$TMPDIR"/patching
+trap 'rm -rf "$PATCHDIR"' EXIT
+
 for module in $GLUON_MODULES; do
 	echo "--- Patching module '$module' ---"
 
-	cd "$GLUONDIR"/$module
-	git checkout -B patching base
+	git clone -s -b base --single-branch "$GLUONDIR"/$module "$PATCHDIR" 2>/dev/null
 
+	cd "$PATCHDIR"
 	for patch in "$GLUONDIR"/patches/$module/*.patch; do
-		if ! git -c user.name='Gluon Patch Manager' -c user.email='gluon@void.example.com' -c commit.gpgsign=false am --whitespace=nowarn --committer-date-is-author-date "$patch"; then
-			git am --abort
-			git checkout patched
-			git branch -D patching
-			exit 1
-		fi
+		git -c user.name='Gluon Patch Manager' -c user.email='gluon@void.example.com' -c commit.gpgsign=false am --whitespace=nowarn --committer-date-is-author-date "$patch"
 	done
-	git branch -M patched
+
+	cd "$GLUONDIR"/$module
+	git fetch "$PATCHDIR" 2>/dev/null
+	git checkout -B patched FETCH_HEAD
+	git submodule update --init --recursive
+
+	rm -rf "$PATCHDIR"
 done
diff --git a/scripts/update.sh b/scripts/update.sh
index 86c69628..8aa98731 100755
--- a/scripts/update.sh
+++ b/scripts/update.sh
@@ -14,8 +14,7 @@ for module in $GLUON_MODULES; do
 	mkdir -p "$GLUONDIR"/$module
 	cd "$GLUONDIR"/$module
 	git init
+	git config commit.gpgsign false
 
-	git checkout $commit 2>/dev/null || git fetch $repo $branch
-	git checkout -B base $commit
-	git submodule update --init --recursive
+	git branch -f base $commit 2>/dev/null || git fetch -f $repo $branch:base
 done