04-ac-femme-fatal.patch

[Akim Demaille]

Sorry for the title of the patch, but this weekend I was listening in
loop to `Andy Warhol' from the Velvet Underground, and especially
`Femme Fatale'.  I couldn't resist (c:

The aim of this patch is fairly simple: spread the use of
_AC_EXPANSION_STACK_DUMP everywhere AC_FATAL is used.

~/src/ace % /tmp                                                     Err 2 remo
/tmp % cat -n aclocal.m4                                             20:43 remo
     1  AC_DEFUN([FOO1],
     2  [AC_REQUIRE([FOO2])])
     3
     4
     5  AC_DEFUN([FOO2],
     6  [AC_REQUIRE([FOO3])])
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18  AC_DEFUN([FOO3],
    19  [AC_LANG_POP
    20  AC_LANG_POP])
/tmp % cat -n configure.in                                           20:43 remo
     1  AC_INIT
     2  FOO1

Before:

| /tmp % ace
| configure.in:2: too many AC_LANG_POP

After:

| /tmp % ace
| configure.in:2: too many AC_LANG_POP
| ./aclocal.m4:20: FOO3 is expanded from...
| configure.in:2: FOO3 is required by...
| ./aclocal.m4:6: FOO2 is expanded from...
| configure.in:2: FOO2 is required by...
| ./aclocal.m4:2: FOO1 is expanded from...
| configure.in:2: the top level

It is debatable whether we should do the same for AC_DIAGNOSE.  It can
be both frightening, and very helping.  I'm in favor of extending it
to AC_DIAGNOSE.  You tell me.

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        * acgeneral.m4 (AC_FATAL): Use _AC_EXPANSION_STACK_DUMP.
        (_AC_REQUIRE): Use AC_FATAL.

Index: TODO
--- TODO Sun, 15 Oct 2000 09:30:12 +0200 akim (ace/29_TODO 1.55 666)
+++ TODO Sun, 15 Oct 2000 20:37:46 +0200 akim (ace/29_TODO 1.55 666)
@@ -9,22 +9,9 @@

 * Autoconf 2.50

-** mktests.sh
-It should be adjusted so that when someone runs it with a failing
-egrep, the output files are touch'ed.
-
 ** AC_EXEEXT, AC_OBJEXT
 We need a good implementation.  As much as possible, they should not
 depend upon AC_EMXOS2 etc.
-
-** More tests
-Check that AC_REQUIRE circular dependencies are caught.
-
-** _AC_EXPANSION_STACK_DUMP
-Where ever AC_FATAL is used, we should call _AC_EXPANSION_STACK_DUMP.
-Try to see if we can use __FILE__ and __LINE__ in the stack: this
-would provide much more accurate error messages (but it might be
-costly...).

 ** --target & AC_ARG_PROGRAM
 Shouldn't *any* `program' be installed as `$target_alias-program' even
Index: acgeneral.m4
--- acgeneral.m4 Sun, 15 Oct 2000 20:19:41 +0200 akim (ace/27_acgeneral. 
1.169.8.71 666)
+++ acgeneral.m4 Sun, 15 Oct 2000 20:37:13 +0200 akim (ace/27_acgeneral. 
1.169.8.71 666)
@@ -655,9 +655,7 @@ define([_AC_REQUIRE],
 [pushdef([_AC_EXPANSION_STACK],
          m4_location[: $1 is required by...])dnl
 ifdef([_AC_EXPANDING($1)],
-      [m4_diagnose([AC_REQUIRE: circular dependency of $1])dnl
-_AC_EXPANSION_STACK_DUMP()dnl
-m4exit(1)])dnl
+      [AC_FATAL([AC_REQUIRE: circular dependency of $1])])dnl
 ifndef([_AC_DIVERT_DUMP],
     [AC_FATAL([AC_REQUIRE: cannot be used outside of an AC_DEFUN'd macro])])dnl
 AC_PROVIDE_IFELSE([$1],
@@ -2763,7 +2761,10 @@ define([AC_WARNING], [AC_DIAGNOSE([synta

 # AC_FATAL(MESSAGE, [EXIT-STATUS])
 # --------------------------------
-define([AC_FATAL], [m4_fatal([$1], [$2])])
+define([AC_FATAL],
+[m4_diagnose([$1])
+_AC_EXPANSION_STACK_DUMP()
+m4exit(m4_default([$2], [1]))])
Index: NEWS
--- NEWS Sun, 15 Oct 2000 09:30:12 +0200 akim (ace/31_NEWS 1.34 666)
+++ NEWS Sun, 15 Oct 2000 21:39:50 +0200 akim (ace/31_NEWS 1.34 666)
@@ -29,6 +29,11 @@
   configure to adapt for packages not using autoconf on case-insensitive
   filesystems.
 
+- Diagnostics
+  More errors are now caught (circular AC_REQUIRE dependencies,
+  AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
+  etc.).  In addition, their location and call stack are given.
+
 ** autoupdate
 autoupdate is much more powerful, and is able to provide the glue code
 which might be needed to move from an old macro to its newer