From af86dc8c52c3cda36f3a7250e8195f5394751d33 Mon Sep 17 00:00:00 2001
From: Axel Burri <axel@tty0.ch>
Date: Tue, 15 Nov 2022 23:06:21 +0100
Subject: [PATCH] btrbk: allow compressors not to have a compression level

Not all compressors support compression level (option `-#`): print a
warning if compress_level is set, and ignore its value for such
compressors.
---
 btrbk | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/btrbk b/btrbk
index e0bffd1..bb910b7 100755
--- a/btrbk
+++ b/btrbk
@@ -719,15 +719,17 @@ sub compress_cmd_text($;$)
 
   if((not $decompress) && defined($def->{level}) && ($def->{level} ne "default")) {
     my $level = $def->{level};
-    if($level < $cc->{level_min}) {
+    if(!defined($cc->{level_min})) {
+      WARN_ONCE "Compression level is not supported for '$cc->{name}', ignoring";
+      $level = undef;
+    } elsif($level < $cc->{level_min}) {
       WARN_ONCE "Compression level capped to minimum for '$cc->{name}': $cc->{level_min}";
       $level = $cc->{level_min};
-    }
-    if($level > $cc->{level_max}) {
+    } elsif($level > $cc->{level_max}) {
       WARN_ONCE "Compression level capped to maximum for '$cc->{name}': $cc->{level_max}";
       $level = $cc->{level_max};
     }
-    push @cmd, '-' . $level;
+    push @cmd, '-' . $level if(defined($level));
   }
   if(defined($def->{threads}) && ($def->{threads} ne "default")) {
     my $thread_opt = $cc->{threads};