[PATCH 2/3] aclocal: remove @automake_includes

[Paolo Bonzini]

This patch simplifies the overly complicated rules for ACLOCAL_PATH
vs. @automake_includes and @system_includes, by stating that
ACLOCAL_PATH will override even @automake_includes.  The simplest
way to achieve this is to remove @automake_includes altogether.

There are two small visible differences here with respect to 1.11:

- "--acdir ${datadir}/prefix/aclocal-VERSION" will treat files
in acdir as FT_AUTOMAKE, and special case them with respect to the
serial number.  This option makes no sense, but I like the new
semantics better.

- if "${datadir}/prefix/aclocal-VERSION" does not exist, aclocal
will not warn about it.  This shouldn't happen anyway, so I think we
can live with this.

The third difference is of course in the semantics of ACLOCAL_PATH.

* NEWS: Adapt to change in ACLOCAL_PATH semantics.
* aclocal.in (default_automake_dir): New.
(scan_file): Use it to distinguish FT_AUTOMAKE from FT_SYSTEM.
(automake_includes): Remove.
(scan_m4_files): Do not scan it.
(have_ac_dir): New.
(parse_arguments): Set it for --acdir instead of automake_includes, use it
to determine whether to filter absent directories out of @system_includes.
Allow >1 directory in @system_includes for --print-ac-dir.
* doc/automake.texi: Adapt to changes in ACLOCAL_PATH semantics.
* tests/acloca25.test: Likewise.
---
 ChangeLog           |   15 +++++++++++++++
 NEWS                |    4 ++--
 aclocal.in          |   36 +++++++++++++++++++++---------------
 doc/automake.texi   |    6 ++----
 tests/acloca25.test |    7 +------
 5 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index fa43c14..ede73dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,20 @@
 2010-11-09  Paolo Bonzini  <address@hidden>
 
+       aclocal: remove @automake_includes.
+       * NEWS: Adapt to changes in ACLOCAL_PATH semantics.
+       * aclocal.in (default_automake_dir): New.
+       (scan_file): Use it to distinguish FT_AUTOMAKE from FT_SYSTEM.
+       (automake_includes): Remove.
+       (scan_m4_files): Do not scan it.
+       (have_ac_dir): New.
+       (parse_arguments): Set it for --acdir instead of automake_includes, use 
it
+       to determine whether to filter absent directories out of 
@system_includes.
+       Allow >1 directory in @system_includes for --print-ac-dir.
+       * doc/automake.texi: Adapt to changes in ACLOCAL_PATH semantics.
+       * tests/acloca25.test: Likewise.
+
+2010-11-09  Paolo Bonzini  <address@hidden>
+
        aclocal: handle ACLOCAL_PATH environment variable.
        * NEWS: Document new behavior.
        * aclocal.in (parse_arguments): Parse ACLOCAL_PATH as a colon-separated
diff --git a/NEWS b/NEWS
index 9dd7860..eb732d9 100644
--- a/NEWS
+++ b/NEWS
@@ -3,8 +3,8 @@ New in 1.11a:
 * Changes to aclocal:
 
   - aclocal now interprets the `ACLOCAL_PATH' environment variable as a
-    colon-separated list of additional directories to search after
-    ${prefix}/share/aclocal-VERSION and before ${prefix}/share/aclocal.
+    colon-separated list of additional directories to search before
+    ${prefix}/share/aclocal-VERSION and ${prefix}/share/aclocal.
 
 * Changes to automake:
 
diff --git a/aclocal.in b/aclocal.in
index 942d8e3..1d73f49 100644
--- a/aclocal.in
+++ b/aclocal.in
@@ -50,16 +50,20 @@ use Cwd;
 # We do not operate in threaded mode.
 $perl_threads = 0;
 
+# This directory is treated specially with respect to serial numbers.
+my $default_automake_dir = "@datadir@/aclocal-$APIVERSION";
+
 # Include paths for searching macros.  We search macros in this order:
 # user-supplied directories first, then the directory containing the
 # automake macros, and finally the system-wide directories for
 # third-party macros.  @user_includes can be augmented with -I.
 # @system_includes can be augmented with the `dirlist' file or
-# ACLOCAL_PATH.  Also --acdir will reset both @automake_includes
-# and @system_includes.
+# ACLOCAL_PATH.
 my @user_includes = ();
-my @automake_includes = ("@datadir@/aclocal-$APIVERSION");
-my @system_includes = ('@datadir@/aclocal');
+my @system_includes = ($default_automake_dir, '@datadir@/aclocal');
+
+# Whether --acdir was passed.
+my $have_acdir = 0;
 
 # Whether we should copy M4 file in $user_includes[0].
 my $install = 0;
@@ -346,7 +350,6 @@ sub scan_m4_files ()
 
   # Finally, scan all files in our search paths.
   scan_m4_dirs (FT_USER, @user_includes);
-  scan_m4_dirs (FT_AUTOMAKE, @automake_includes);
   scan_m4_dirs (FT_SYSTEM, @system_includes);
 
   # Construct a new function that does the searching.  We use a
@@ -464,8 +467,8 @@ my $underquoted_manual_once = 0;
 # --------------------------------
 # Scan a single M4 file ($FILE), and all files it includes.
 # Return the list of included files.
-# $TYPE is one of FT_USER, FT_AUTOMAKE, or FT_SYSTEM, depending
-# on where the file comes from.
+# $TYPE is one of FT_USER or FT_SYSTEM, depending on where
+# the file comes from.
 # $WHERE is the location to use in the diagnostic if the file
 # does not exist.
 sub scan_file ($$$)
@@ -480,6 +483,9 @@ sub scan_file ($$$)
 
   unshift @file_order, $file;
 
+  $type = FT_AUTOMAKE
+    if $type == FT_SYSTEM && $default_automake_dir eq dirname $file;
+
   $file_type{$file} = $type;
 
   fatal "$where: file `$file' does not exist" if ! -e $file;
@@ -932,7 +938,7 @@ sub parse_arguments ()
      'acdir=s'         => sub # Setting --acdir overrides both the
                              { # automake (versioned) directory and the
                               # public (unversioned) system directory.
-                              @automake_includes = ();
+                              $have_acdir = 1;
                               @system_includes = ($_[1])
                             },
      'diff:s'          => \$diff_command,
@@ -997,7 +1003,8 @@ sub parse_arguments ()
 
   if ($print_and_exit)
     {
-      print "@system_includes\n";
+      my $acdir = $system_includes[$#system_includes];
+      print "$acdir\n";
       exit 0;
     }
 
@@ -1015,16 +1022,15 @@ sub parse_arguments ()
             . "\nfirst -I option, but no -I was supplied");
     }
 
-  if (! -d $system_includes[0])
+  if (! $have_acdir)
     {
       # By default $(datadir)/aclocal doesn't exist.  We don't want to
       # get an error in the case where we are searching the default
-      # directory and it hasn't been created.  (We know
-      # @system_includes has its default value if @automake_includes
-      # is not empty, because --acdir is the only way to change this.)
-      @system_includes = () if @automake_includes;
+      # directory and it hasn't been created.
+      @system_includes = grep { -d } @system_includes;
     }
-  else
+
+  if (length @system_includes > 0)
     {
       # Add any directory listed in the `dirlist' file.
       if (open (DIRLIST, "$system_includes[0]/dirlist"))
diff --git a/doc/automake.texi b/doc/automake.texi
index 9c548fd..d128e29 100644
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -3368,10 +3368,8 @@ Macro Search Path
 also the simplest.  Any directory included in the colon-separated
 environment variable @env{ACLOCAL_PATH} is added to the search path
 and takes precedence over system directories (including those found
-via @file{dirlist}), with the exception of the versioned directory
address@hidden@var{prefix}/share/address@hidden  However, directories
-passed via @option{-I} will take precedence over directories in
-ACLOCAL_PATH.
+via @file{dirlist}).  However, directories passed via @option{-I}
+will take precedence over directories in ACLOCAL_PATH.
 
 Conversely to @file{dirlist}, @env{ACLOCAL_PATH} is useful if you are
 using a global copy of Automake and want @command{aclocal} to look for
diff --git a/tests/acloca25.test b/tests/acloca25.test
index 14c8892..5cdd1b8 100755
--- a/tests/acloca25.test
+++ b/tests/acloca25.test
@@ -60,12 +60,7 @@ $FGREP '!!FAIL-FOO!!' configure && Exit 1
 $FGREP '~~PASS-BAR~~' configure
 $FGREP '//FAIL-BAR//' configure && Exit 1
 # Directories in ACLOCAL_PATH should take precedence over system
-# directories, typically ${prefix}/share/aclocal.  Note that directories
-# in ACLOCAL_PATH do _not_ take precedence over the internal automake
-# directory ${prefix}/share/aclocal-VERSION, and AM_INIT_AUTOMAKE would
-# normally be found there; however, the testsuite is run with --acdir,
-# so the place of ${srcdir}/m4 in the search path is exactly what
-# ACLOCAL_PATH overrides.
+# directories, i.e. ${prefix}/share/aclocal and /share/aclocal-VERSION.
 $FGREP '%%blablabla%%' configure
 
 :
-- 
1.7.3.2