[PATCH 1/2] aclocal: just warn if the primary local m4 dir doesn't exist (no error)

[Pavel Raiskup]

Related to automake bug#13514.

Every bootstrapping process which does not need to have the local
macro directory existing in version control system (because it does
not have any user-defined macros) would fail during 'autoreconf -vfi'
phase if the AC_CONFIG_MACRO_DIRS([m4]) is specified (to force tools
like 'autopoint' and 'libtoolize' to use 'm4' as the local directory
where to install definitions of their m4 macros, and to instruct
aclocal to look into it):

  autoreconf: Entering directory `.'
  autoreconf: running: aclocal --force
  aclocal: error: couldn't open directory 'm4': No such file or directory
  autoreconf: aclocal failed with exit status: 1

The problem is that when the 'aclocal' is run for the first time
during 'autoreconf', the directory 'm4' does not exist yet.  It will
be created by e.g. by 'libtoolize' later on.  During the second run
(after 'libtoolize'), the 'm4' directory exists and aclocal does not
complain.

For that reason, we degrade the error to a simple warning.  The
warning is quite useful for running aclocal by hand - so we are not
removing completely.

See:
<http://lists.gnu.org/archive/html/bug-automake/2013-01/msg00115.html>
<http://lists.gnu.org/archive/html/automake-patches/2010-02/msg00030.html>

* aclocal.in (SCAN_M4_DIRS_SILENT, SCAN_M4_DIRS_WARN)
(SCAN_M4_DIRS_ERROR): New constants.
(scan_m4_dirs): Change the second parameter name to $ERR_LEVEL to
better reflect new semantic. Use new constants.
(scan_m4_files): Adjust to reflect the new 'scan_m4_dirs' semantics.
* t/aclocal-macrodir.tap: Check for proper return value of 'aclocal'
when AC_CONFIG_MACRO_DIR is specified.  Check whether warning is (is
not) printed to stderr when the primary macro directory does not
exist.

Suggested-by: Ben Pfaff <address@hidden>
---
 aclocal.in             | 31 +++++++++++++++++++++++--------
 t/aclocal-macrodir.tap | 12 ++++++++----
 2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/aclocal.in b/aclocal.in
index b51c09d..8bae156 100644
--- a/aclocal.in
+++ b/aclocal.in
@@ -165,6 +165,11 @@ my @ac_config_macro_dirs;
 # If set, names a temporary file that must be erased on abnormal exit.
 my $erase_me;
 
+# constants for scan_m4_dirs($ERR_LEVEL) parameter
+use constant SCAN_M4_DIRS_SILENT => 0;
+use constant SCAN_M4_DIRS_WARN => 1;
+use constant SCAN_M4_DIRS_ERROR => 2;
+
 ################################################################
 
 # Prototypes for all subroutines.
@@ -355,21 +360,29 @@ sub list_compare (address@hidden@)
 
 ################################################################
 
-# scan_m4_dirs($TYPE, $ERR_ON_NONEXISTING, @DIRS)
+# scan_m4_dirs($TYPE, $ERR_LEVEL, @DIRS)
 # -----------------------------------------------
 # Scan all M4 files installed in @DIRS for new macro definitions.
 # Register each file as of type $TYPE (one of the FT_* constants).
+# Fail without discussion on non-existing include directory when the
+# $ERR_LEVEL parameter equals to SCAN_M4_DIRS_ERROR, just print warning
+# when it equals to SCAN_M4_DIRS_WARN and don't complain at all when
+# it is set to SCAN_M4_DIRS_SILENT.
 sub scan_m4_dirs ($$@)
 {
-  my ($type, $err_on_nonexisting, @dirlist) = @_;
+  my ($type, $err_level, @dirlist) = @_;
 
   foreach my $m4dir (@dirlist)
     {
       if (! opendir (DIR, $m4dir))
        {
          # TODO: maybe avoid complaining only if errno == ENONENT?
-         next unless $err_on_nonexisting;
-         fatal "couldn't open directory '$m4dir': $!";
+         my $message = "couldn't open directory '$m4dir': $!";
+
+         fatal $message if $err_level == SCAN_M4_DIRS_ERROR;
+         msg ('unsupported', $message) if $err_level == SCAN_M4_DIRS_WARN;
+         # don't complain if $err_level == SCAN_M4_DIRS_SILENT
+         next
        }
 
       # We reverse the directory contents so that foo2.m4 gets
@@ -408,11 +421,13 @@ sub scan_m4_files ()
     {
       # Don't complain if the first user directory doesn't exist, in case
       # we need to create it later (can happen if '--install' was given).
-      scan_m4_dirs (FT_USER, !$install, $user_includes[0]);
-      scan_m4_dirs (FT_USER, 1, @user_includes[1..$#user_includes]);
+      my $first_dir_lvl = $install ? SCAN_M4_DIRS_SILENT : SCAN_M4_DIRS_WARN;
+      scan_m4_dirs (FT_USER, $first_dir_lvl, $user_includes[0]);
+      scan_m4_dirs (FT_USER, SCAN_M4_DIRS_ERROR,
+                   @user_includes[1..$#user_includes]);
     }
-  scan_m4_dirs (FT_AUTOMAKE, 1, @automake_includes);
-  scan_m4_dirs (FT_SYSTEM,   1, @system_includes);
+  scan_m4_dirs (FT_AUTOMAKE, SCAN_M4_DIRS_ERROR, @automake_includes);
+  scan_m4_dirs (FT_SYSTEM, SCAN_M4_DIRS_ERROR, @system_includes);
 
   # Construct a new function that does the searching.  We use a
   # function (instead of just evaluating $search in the loop) so that
diff --git a/t/aclocal-macrodir.tap b/t/aclocal-macrodir.tap
index 3c66e53..4673d71 100755
--- a/t/aclocal-macrodir.tap
+++ b/t/aclocal-macrodir.tap
@@ -105,7 +105,9 @@ mkdir sys-dir the-dir
 echo 'AC_DEFUN([THE_MACRO], [:])' > sys-dir/my.m4
 
 test ! -r the-dir/my.m4 \
-  && $ACLOCAL --install --system-acdir ./sys-dir \
+  && $ACLOCAL --install --system-acdir ./sys-dir 2>stderr \
+  && cat stderr >&2 \
+  && not grep "couldn't open directory" stderr \
   && diff sys-dir/my.m4 the-dir/my.m4 \
   || r='not ok'
 
@@ -149,7 +151,9 @@ mkdir acdir
 echo 'AC_DEFUN([MY_MACRO], [:])' > acdir/bar.m4
 
 test ! -d foo \
-  && $ACLOCAL --install --system-acdir ./acdir \
+  && $ACLOCAL --install --system-acdir ./acdir 2>stderr \
+  && cat stderr >&2 \
+  && not grep "couldn't open directory" stderr \
   && diff acdir/bar.m4 foo/bar.m4 \
   || r='not ok'
 
@@ -157,14 +161,14 @@ test_end
 
 #---------------------------------------------------------------------------
 
-test_begin "AC_CONFIG_MACRO_DIR([non-existent]) errors out (1)"
+test_begin "AC_CONFIG_MACRO_DIR([non-existent]) warns but succeeds"
 
 cat > configure.ac << 'END'
 AC_INIT([oops], [1.0])
 AC_CONFIG_MACRO_DIR([non-existent])
 END
 
-not $ACLOCAL -Wnone 2>stderr \
+$ACLOCAL -Wno-error 2>stderr \
   && cat stderr >&2 \
   && grep "couldn't open directory 'non-existent'" stderr \
   || r='not ok'
-- 
1.7.11.7