Re: [PATCH 6/6] use print or printf or cat as $ECHO (really)

[Ralf Wildenhues]

* Eric Blake wrote on Sun, Nov 23, 2008 at 03:26:41PM CET:
> According to Ralf Wildenhues on 11/23/2008 1:10 AM:
> > Are we certain enough no bash or zsh version has problems with a long
> > format string?
> 
> I'm not certain they are bug-free on all possible formats (for example,
> printf %100000s\\n), but for our usage, they do just fine on long strings
> where Solaris /bin/printf does not.

OK, let's leave it at that for now.

> Still not enough.  Solaris /bin/sh correctly fails this test.  However,
> because we did not check for print, Solaris ksh _also_ fails the test, and
> we end up wrongly favoring /bin/sh, even though it lacks a builtin.  On
> Solaris, we _want_ to choose ksh over /bin/sh, because builtin print is
> faster than the here-doc fallback used in /bin/sh.  I think the last line
> has to be:
> 
>    ( PATH=/empty FPATH=/empty; export PATH FPATH
>      test "X`printf %s $ECHO`" = "X$ECHO" \
>        || test "X`print -r -- $ECHO`" = "X$ECHO" ) }])])

Thanks for testing.  I've pushed this now.

Cheers,
Ralf

2008-11-23  Ralf Wildenhues  <address@hidden>
            Eric Blake  <address@hidden>

        Fix $ECHO test to not influence other _AS_DETECT_SUGGESTED code.
        * libltdl/m4/libtool.m4 (_LT_PROG_ECHO_BACKSLASH): Fix test to
        not influence further tests registered with _AS_DETECT_SUGGESTED
        and do not use a PATH below /tmp, to avoid influence by a third
        party.

diff --git a/libltdl/m4/libtool.m4 b/libltdl/m4/libtool.m4
index 633d8f8..5d1a131 100644
--- a/libltdl/m4/libtool.m4
+++ b/libltdl/m4/libtool.m4
@@ -1114,12 +1114,13 @@ esac
 
 m4_ifdef([_AS_DETECT_SUGGESTED],
 [_AS_DETECT_SUGGESTED([
-  
ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
-  ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
-  ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
-  PATH=/tmp/nonexistent; export PATH;
-  FPATH=$PATH; export FPATH;
-  test "X`printf %s $ECHO`" = "X$ECHO"])])
+  test -n "${ZSH_VERSION+set}${BASH_VERSION+set}" || (
+    
ECHO='\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'
+    ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO
+    ECHO=$ECHO$ECHO$ECHO$ECHO$ECHO$ECHO
+    PATH=/empty FPATH=/empty; export PATH FPATH
+    test "X`printf %s $ECHO`" = "X$ECHO" \
+      || test "X`print -r -- $ECHO`" = "X$ECHO" )])])
 
 _LT_DECL([], [SHELL], [1], [Shell to use when invoking shell scripts])
 _LT_DECL([], [ECHO], [1], [An echo program that protects backslashes])