From: Eric Blake <ebb9@byu.net>
Date: Wed, 15 Oct 2008 22:15:52 +0000 (-0600)
Subject: Break circular require chain in _AS_LINENO_PREPARE.
X-Git-Tag: v2.63b~248
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7eba1c0ae03df9227cbd6ec47893395d72e2ef0f;p=thirdparty%2Fautoconf.git

Break circular require chain in _AS_LINENO_PREPARE.

* lib/m4sugar/m4sh.m4 (_AS_LINENO_PREPARE): Ensure that logging is
disabled when reporting LINENO failure, since logging requires
LINENO.
* doc/autoconf.texi (Initialization Macros): Recommend m4_pushdef,
not m4_rename, since the latter is undocumented.
* lib/autoconf/status.m4 (_AC_OUTPUT_CONFIG_STATUS): Avoid
m4_rename, as it does not yet handle pushdef stacks.
Reported by Ralf Wildenhues.

Signed-off-by: Eric Blake <ebb9@byu.net>
---

diff --git a/ChangeLog b/ChangeLog
index d4619b9b..e627d14f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2008-10-15  Eric Blake  <ebb9@byu.net>
+
+	Break circular require chain in _AS_LINENO_PREPARE.
+	* lib/m4sugar/m4sh.m4 (_AS_LINENO_PREPARE): Ensure that logging is
+	disabled when reporting LINENO failure, since logging requires
+	LINENO.
+	* doc/autoconf.texi (Initialization Macros): Recommend m4_pushdef,
+	not m4_rename, since the latter is undocumented.
+	* lib/autoconf/status.m4 (_AC_OUTPUT_CONFIG_STATUS): Avoid
+	m4_rename, as it does not yet handle pushdef stacks.
+	Reported by Ralf Wildenhues.
+
 2008-10-15  Eric Blake  <ebb9@byu.net>
 
 	Cleanups to previous patches.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index b3ffc766..43227a6b 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -11978,11 +11978,14 @@ Note that @code{AS_INIT_GENERATED} does not emit the entire prolog.
 In particular, a line containing @code{#!$SHELL} must have already been
 emitted to the child script; you should not use @code{#!/bin/sh}, or the
 child script will not use the more modern shell that the parent script
-might have detected.  Currently, the suggested idiom for writing a M4sh
+might have detected.  Likewise, the child script starts life without a
+log file open, so you must temporarily disable any attempts to use the
+log file until after emitting code to open a log within the child.
+Currently, the suggested idiom for writing a M4sh
 shell script from within another script is:
 
 @example
-m4_rename([AS_MESSAGE_LOG_FD], [save_AS_MESSAGE_LOG_FD])dnl
+m4_pushdef([AS_MESSAGE_LOG_FD])dnl
 cat > "@var{file}" <<__EOF__
 #! $SHELL
 # Generated by $as_me.
@@ -11995,7 +11998,7 @@ cat >>"@var{file}" <<\__EOF__
 AS_INIT_GENERATED
 # ...
 __EOF__
-m4_rename([save_AS_MESSAGE_LOG_FD], [AS_MESSAGE_LOG_FD])dnl
+m4_popdef([AS_MESSAGE_LOG_FD])dnl
 @end example
 
 This, however, may change in the future as the M4sh interface is
diff --git a/lib/autoconf/status.m4 b/lib/autoconf/status.m4
index 6d622b9e..26fa2cff 100644
--- a/lib/autoconf/status.m4
+++ b/lib/autoconf/status.m4
@@ -1317,7 +1317,7 @@ fi
 m4_define([_AC_OUTPUT_CONFIG_STATUS],
 [AC_MSG_NOTICE([creating $CONFIG_STATUS])
 dnl AS_MESSAGE_LOG_FD is not available yet:
-m4_rename([AS_MESSAGE_LOG_FD], [_AC_save_AS_MESSAGE_LOG_FD])dnl
+m4_pushdef([AS_MESSAGE_LOG_FD])dnl
 cat >$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 #! $SHELL
 # Generated by $as_me.
@@ -1541,7 +1541,7 @@ fi
 _ACEOF
 cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 dnl Open the log:
-m4_rename([_AC_save_AS_MESSAGE_LOG_FD], [AS_MESSAGE_LOG_FD])dnl
+m4_popdef([AS_MESSAGE_LOG_FD])dnl
 exec AS_MESSAGE_LOG_FD>>config.log
 {
   echo
diff --git a/lib/m4sugar/m4sh.m4 b/lib/m4sugar/m4sh.m4
index b42e87fa..44c80491 100644
--- a/lib/m4sugar/m4sh.m4
+++ b/lib/m4sugar/m4sh.m4
@@ -953,6 +953,9 @@ m4_defun([_AS_LINENO_PREPARE],
 [AS_REQUIRE([_AS_CR_PREPARE])dnl
 AS_REQUIRE([_AS_ME_PREPARE])dnl
 _AS_DETECT_SUGGESTED([_AS_LINENO_WORKS])dnl
+dnl Even if the logging fd is open, we don't want to use $LINENO in the
+dnl AS_ERROR complaining that LINENO is broken.
+m4_pushdef([AS_MESSAGE_LOG_FD])dnl
 _AS_LINENO_WORKS || {
 
   dnl Create $as_me.lineno as a copy of $as_myself, but with $LINENO
@@ -989,6 +992,7 @@ _AS_LINENO_WORKS || {
   # Exit status is that of the last command.
   exit
 }
+m4_popdef([AS_MESSAGE_LOG_FD])dnl
 ])# _AS_LINENO_PREPARE