Fix off by one error in default update script

data/config

@@ -54,8 +54,9 @@ AudioScrollSpeed: 5
 
 # Command that is run to check if there are out-of-date packages.
 # The script should return *ONLY* a number. If it doesn't output a number, updates are no longer checked.
-# Default value is applicable for Arch Linux. (See src/Config.h for explanation on the default command)
+# Default value is applicable for Arch Linux. (See data/update.sh for a human-readable version)
-CheckPackagesCommand: pac="$(checkupdates)"; if [ $? -eq 127 ] ; then exit 127; fi; echo -n "$pac" | wc -l
+CheckPackagesCommand: p="$(checkupdates)"; e=$?; if [ $e -eq 127 ] ; then exit 127; fi; if [ $e -eq 2 ] ; then echo "0" && exit 0; fi; echo "$p" | wc -l
+
 
 # How often to check for updates. In seconds
 CheckUpdateInterval: 300

data/update.sh

@@ -0,0 +1,23 @@
+#/bin/sh
+
+# This script is not used by default. It is a human-readable version of the default Arch-applicable
+# package command with explanations
+
+updates="$(checkupdates)";
+exitCode=$?;
+
+if [ $exitCode -eq 127 ] ; then
+    # checkupdates wasn't found.
+    # Forward the error to gBar, so gBar can shut down the widget
+    # This is done, so we don't bother non-Arch systems with update checking
+    exit 127;
+fi
+
+if [ $exitCode -eq 2 ] ; then
+    # Zero packages out-of-date. We need to handle this case, since 'echo "$updates" | wc -l' would return 1
+    echo "0" && exit 0
+fi
+
+# We need the extra newline (-n option omitted), since 'echo -n $"updates" | wc -l' is off by one,
+# since 'echo -n $"updates"' has a \0 at the end
+echo "$updates" | wc -l

src/Config.h

@@ -17,9 +17,8 @@ public:
     std::string defaultWorkspaceSymbol = "";
 
     // Script that returns how many packages are out-of-date. The script should only print a number!
-    // The default script runs checkupdates, and forcefully exits when checkupdates is not found, so gBar can disable the package widget.
+    // See data/update.sh for a human-readable version
-    // "checkupdates | wc -l" would always return 0 on stdout, which gBar accepts
+    std::string checkPackagesCommand = "p=\"$(checkupdates)\"; e=$?; if [ $e -eq 127 ] ; then exit 127; fi; if [ $e -eq 2 ] ; then echo \"0\" && exit 0; fi; echo \"$p\" | wc -l";
-    std::string checkPackagesCommand = "pac=\"$(checkupdates)\"; if [ $? -eq 127 ] ; then exit 127; fi; echo -n \"$pac\" | wc -l";
 
     bool centerTime = true;
     bool audioRevealer = false;

src/System.cpp

@@ -563,10 +563,10 @@ namespace System
                 ASSERT(feof(pipe), "GetOutdatedPackages: Cannot read to eof!");
 
                 int exitCode = pclose(pipe) / 256;
-                if (exitCode == 127)
+                if (exitCode != 0)
                 {
                     configMutex.lock();
-                    // Invalid script
+                    // Invalid script/error
                     LOG("GetOutdatedPackages: Invalid command. Disabling package widget!");
                     RuntimeConfig::Get().hasPackagesScript = false;
                     configMutex.unlock();