From d59986cbc3f63035b2b37f5ef5041b8de6ab2d9f Mon Sep 17 00:00:00 2001
From: nicok1 <34523672+nicok1@users.noreply.github.com>
Date: Fri, 23 Feb 2024 14:40:29 +0100
Subject: [PATCH] Offer rollback option for interactive upgrading  (#11771)

---
 cmd/check_config.go             | 29 +++++++++++++++++
 packaging/scripts/postremove.sh | 56 +++++++++++++++++++++++++++++++++
 packaging/scripts/preinstall.sh |  2 +-
 3 files changed, 86 insertions(+), 1 deletion(-)
 create mode 100644 cmd/check_config.go

diff --git a/cmd/check_config.go b/cmd/check_config.go
new file mode 100644
index 000000000..ad0cc23e8
--- /dev/null
+++ b/cmd/check_config.go
@@ -0,0 +1,29 @@
+package cmd
+
+import (
+	_ "embed"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var checkconfig = &cobra.Command{
+	Use:   "checkconfig",
+	Short: "Check config file for errors",
+	Run:   runConfigCheck,
+}
+
+func init() {
+	rootCmd.AddCommand(checkconfig)
+}
+
+func runConfigCheck(cmd *cobra.Command, args []string) {
+	err := loadConfigFile(&conf)
+
+	if err != nil {
+		log.FATAL.Println("config invalid:", err)
+		os.Exit(1)
+	} else {
+		log.INFO.Println("config valid")
+	}
+}
diff --git a/packaging/scripts/postremove.sh b/packaging/scripts/postremove.sh
index 4de8d7878..5baac5cb4 100644
--- a/packaging/scripts/postremove.sh
+++ b/packaging/scripts/postremove.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 set -e
 
 if [ -d /run/systemd/system ]; then
@@ -15,4 +16,59 @@ if [ "$1" = "purge" ]; then
 		deb-systemd-helper purge evcc.service >/dev/null || true
 		deb-systemd-helper unmask evcc.service >/dev/null || true
 	fi
+fi
+
+
+
+
+# if interactive: Call /usr/bin/evcc checkconfig and capture the output (newer version)
+# if output contains "config valid" then do nothing
+# else: Ask user if he wants to keep the old version (working) or the new version (not working) 
+# Remember the choice with /tmp/.evccrollback and fail new-postrm failed-upgrade old-version new-version to initiate dpkg's rollback
+if [ "$1" = "upgrade" ]; then
+	INTERACTIVE=0
+	# is shell script interactive?
+	if [ -t 0 ]; then
+	  INTERACTIVE=1
+	else
+	  INTERACTIVE=0
+	fi
+
+	if [ $INTERACTIVE -eq 1 ]; then
+	    checkConfigOutput=$(/usr/bin/evcc checkconfig 2>&1 || true)
+		if ! echo "$checkConfigOutput" | grep -q "config valid"; then
+			echo "--------------------------------------------------------------------------------"
+			echo "ERROR: your evcc configuration is not compatible with the new version. Please consider reading the release notes: https://github.com/evcc-io/evcc/releases"
+			echo "checkconfig Output:" 
+			echo "$checkConfigOutput"
+			echo "--------------------------------------------------------------------------------"
+	
+			while true; do
+				echo "Do you want to keep your old (working) evcc version? [Y/n]: "
+				read choice
+				case "$choice" in
+					n*|N*|"")
+						echo "We will keep the new version. Your evcc configuration stays untouched!"
+						break
+						;;
+					y*|Y*)
+						echo "The old version will be restored. Your evcc configuration stays untouched! Following errors are intended:"
+						touch /tmp/.evccrollback
+						exit 1
+						break
+						;;
+					*)
+						;;
+				esac
+			done
+		fi
+	fi 
+fi
+
+# if upgrade goal fails, new-postrm failed-upgrade old-version new-version is called. It should fail to initiate rollback
+if [ "$1" = "failed-upgrade" ]; then
+	if [ -f "/tmp/.evccrollback" ]; then
+		rm "/tmp/.evccrollback"
+		exit 1
+	fi
 fi
\ No newline at end of file
diff --git a/packaging/scripts/preinstall.sh b/packaging/scripts/preinstall.sh
index 0c8f563eb..17ee90882 100644
--- a/packaging/scripts/preinstall.sh
+++ b/packaging/scripts/preinstall.sh
@@ -101,4 +101,4 @@ if [ "$1" = "upgrade" ]; then
     copyDbToUserDir
 fi
 
-exit 0
+exit 0
\ No newline at end of file