From 8b5078f47fd44e8c2b1eee8e21d6c14ee1a36ccf Mon Sep 17 00:00:00 2001
From: Michele Locati <michele@locati.it>
Date: Thu, 23 Jan 2020 14:50:55 +0100
Subject: [PATCH] Restore previously installed APT packages

---
 install-php-extensions | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/install-php-extensions b/install-php-extensions
index 4b1d4eb..a0ebb61 100755
--- a/install-php-extensions
+++ b/install-php-extensions
@@ -199,6 +199,7 @@ sortModulesToInstall() {
 # Set:
 #   PACKAGES_PERSISTENT
 #   PACKAGES_VOLATILE
+#   PACKAGES_PREVIOUS
 buildRequiredPackageLists() {
 	buildRequiredPackageLists_persistent=''
 	buildRequiredPackageLists_volatile=''
@@ -634,6 +635,7 @@ buildRequiredPackageLists() {
 	done
 	PACKAGES_PERSISTENT=''
 	PACKAGES_VOLATILE=''
+	PACKAGES_PREVIOUS=''
 	if test -z "$buildRequiredPackageLists_persistent$buildRequiredPackageLists_volatile"; then
 		return
 	fi
@@ -643,7 +645,6 @@ buildRequiredPackageLists() {
 			;;
 		debian)
 			DEBIAN_FRONTEND=noninteractive apt-get update -q
-			DEBIAN_FRONTEND=noninteractive apt-get autoremove --purge -y -q
 			;;
 	esac
 	if test -n "$buildRequiredPackageLists_persistent"; then
@@ -665,6 +666,13 @@ buildRequiredPackageLists() {
 		done
 		PACKAGES_VOLATILE="${PACKAGES_VOLATILE# }"
 	fi
+	if test -n "$PACKAGES_PERSISTENT$PACKAGES_VOLATILE"; then
+		case "$buildRequiredPackageLists_distro" in
+			debian)
+				PACKAGES_PREVIOUS="$(dpkg --get-selections | grep -E '\sinstall$' | awk '{ print $1 }')"
+				;;
+		esac
+	fi
 }
 
 # Get the full list of APT/APK packages that will be installed, given the required packages
@@ -1290,6 +1298,14 @@ cleanup() {
 				;;
 		esac
 	fi
+	if test -n "$PACKAGES_PREVIOUS"; then
+		case "$cleanup_distro" in
+			debian)
+				printf '### RESTORING PREVIOUSLY INSTALLED PACKAGES ###\n'
+				DEBIAN_FRONTEND=noninteractive apt-get install -qqy $PACKAGES_PREVIOUS
+				;;
+		esac
+	fi
 	case "$cleanup_distro" in
 		alpine)
 			rm -rf /var/cache/apk/*