- Don't require correct exit status from LESSOPEN scripts

less-436-empty-lessopen-pipe.patch

@@ -1,6 +1,24 @@
---- less-436/filename.c	2009-07-06 22:52:23.000000000 +0200
-+++ less-436_vvitek/filename.c	2010-12-08 16:01:41.269695932 +0100
-@@ -879,17 +879,32 @@ open_altfile(filename, pf, pfd)
+diff -rup less-436-orig/filename.c less-436/filename.c
+--- less-436-orig/filename.c	2009-07-06 22:52:23.000000000 +0200
++++ less-436/filename.c	2011-02-09 16:36:59.508940154 +0100
+@@ -843,6 +843,16 @@ open_altfile(filename, pf, pfd)
+ #else
+ 		lessopen++;
+ 		returnfd = 1;
++
++		if (*lessopen == '|') {
++			/*
++			 * If there is another vertical bar |, after
++			 * the first one, it indicates a "pipe preprocessor"
++			 * with correct exit status.
++			 */
++			lessopen++;
++			returnfd = 2;
++		}
+ #endif
+ 	}
+ 	if (*lessopen == '-') {
+@@ -879,17 +888,32 @@ open_altfile(filename, pf, pfd)
  		 */
  		f = fileno(fd);
  		SET_BINARY(f);
@@ -10,11 +28,11 @@
  		{
  			/*
 -			 * Pipe is empty.  This means there is no alt file.
-+			 * Error or pipe is empty. Close it and
++			 * Error or pipe is empty. Close it and eventually
 +			 * check exit status of the pipe process.
  			 */
 -			pclose(fd);
-+			if (pclose(fd) == 0) {
++			if (pclose(fd) == 0 && returnfd == 2) {
 +				/*
 +				 * Exit status was zero, so the EOF was correct
 +				 * empty output. Let the program open /dev/null
@@ -37,3 +55,33 @@
  		return (save("-"));
  	}
  #endif
+diff -rup less-436-orig/less.nro less-436/less.nro
+--- less-436-orig/less.nro	2011-02-09 16:00:12.520936431 +0100
++++ less-436/less.nro	2011-02-09 16:30:33.161235986 +0100
+@@ -1147,11 +1147,26 @@ lesspipe.sh:
+ .br
+ 		;;
+ .br
++	*)	exit 1
++.br
++		;;
++.br
+ 	esac
+ .br
++	exit $?
++.br
+ .PP
+ To use this script, put it where it can be executed and set
+ LESSOPEN="|lesspipe.sh %s".
++.PP
++The script should return zero if the output was valid and non-zero
++otherwise, so less could detect even a valid empty output
++(for example while uncompressing gzipped empty file).
++For backward-compatibility, this is not required by default. To turn
++this functionality there should be another vertical bar (|) straight
++after the first one in the LESSOPEN environment variable, eg.
++LESSOPEN="||lesspipe.sh %s".
++.PP
+ When an input pipe is used, a LESSCLOSE postprocessor can be used,
+ but it is usually not necessary since there is no replacement file
+ to clean up.

less.csh

@@ -1,4 +1,4 @@
 # less initialization script (csh)
 if ( -x /usr/bin/lesspipe.sh ) then
-  setenv LESSOPEN "|/usr/bin/lesspipe.sh %s"
+  setenv LESSOPEN "||/usr/bin/lesspipe.sh %s"
 endif

less.spec

@@ -72,12 +72,16 @@ ls -la $RPM_BUILD_ROOT/etc/profile.d
 rm -rf $RPM_BUILD_ROOT
 
 %changelog
+- Don't require correct exit status from LESSOPEN scripts until
+  it gets accepted by upstream (preserve backward compatibility)
+  Resolves: #666084, #676057
+
 * Mon Feb 07 2011 Fedora Release Engineering <rel-eng@lists.fedoraproject.org> - 436-10
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_15_Mass_Rebuild
 
 * Mon Jan 03 2011 Vojtech Vitek (V-Teq) <vvitek@redhat.com> - 436-9
 - Fix regression in lesspipe.sh script (*.gz files etc.)
-  Resolves #615303 (comment #9)
+  Resolves: #615303 (comment #9)
 
 * Wed Dec 22 2010 Vojtech Vitek (V-Teq) <vvitek@redhat.com> - 436-8
 - The new "--old-bot" option is not documented in the man page

lesspipe.sh

@@ -3,9 +3,13 @@
 # To use this filter with less, define LESSOPEN:
 # export LESSOPEN="|/usr/bin/lesspipe.sh %s"
 #
-# Script should return zero on success. This is important in case
-# of empty output of any decompressor when the output pipe produces
-# just EOF (eg. while uncompressing gzipped empty file).
+# The script should return zero if the output was valid and non-zero
+# otherwise, so less could detect even a valid empty output
+# (for example while uncompressing gzipped empty file).
+# For backward-compatibility, this is not required by default. To turn
+# this functionality there should be another vertical bar (|) straight
+# after the first one in the LESSOPEN environment variable:
+# export LESSOPEN="||/usr/bin/lesspipe.sh %s"
 
 lesspipe() {
   case "$1" in