[Automake-NG] [FYI] [ng] tags: rewrite to be included verbatim

[Stefano Lattarini]

* lib/am/tags.am: Moved ...
* lib/am/tags.mk: ... here, rewrite to be included verbatim, reformatted,
and enhanced to take over the role of ...
* automake.in (handle_tags): ... this function as well, which has thus
been removed.
(generate_makefile): Call the removed function no more.  Include 'tags.mk'
verbatim in the generated Makefile.
* Makefile.am (dist_am_DATA): Adjust.
* t/tags.sh: This weak grepping test is broken by the other changes done
here; so remove it, adding ...
* t/tags-id.sh: ... this in its place, which is more semantic, i.e.,
operated by actually running the 'ID' target.
* t/tags2.sh: Remove as obsolete.
* t/location.sh: Adjust to avoid spurious errors.
* t/targetclash.sh: Likewise.

Signed-off-by: Stefano Lattarini <address@hidden>
---
 Makefile.am                 |   2 +-
 automake.in                 |  32 +-----------
 lib/am/{tags.am => tags.mk} | 122 +++++++++++++++++++++++---------------------
 t/location.sh               |   8 +--
 t/{tags.sh => tags-id.sh}   |  19 ++++++-
 t/tags2.sh                  |  42 ---------------
 t/targetclash.sh            |   4 +-
 7 files changed, 89 insertions(+), 140 deletions(-)
 rename lib/am/{tags.am => tags.mk} (62%)
 rename t/{tags.sh => tags-id.sh} (78%)
 delete mode 100755 t/tags2.sh

diff --git a/Makefile.am b/Makefile.am
index f85663c..d2f014f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -193,6 +193,7 @@ dist_am_DATA = \
   lib/am/check-typos.mk \
   lib/am/clean.mk \
   lib/am/header-vars.mk \
+  lib/am/tags.mk \
   lib/am/compile.am \
   lib/am/configure.am \
   lib/am/data.am \
@@ -217,7 +218,6 @@ dist_am_DATA = \
   lib/am/remake-hdr.am \
   lib/am/scripts.am \
   lib/am/subdirs.am \
-  lib/am/tags.am \
   lib/am/texi-vers.am \
   lib/am/texi-spec.am \
   lib/am/texinfos.am \
diff --git a/automake.in b/automake.in
index 5acd434..c50e0ad 100644
--- a/automake.in
+++ b/automake.in
@@ -3147,36 +3147,6 @@ sub handle_data
                     'pkgdata', 'lisp', 'noinst', 'check');
 }
 
-# Handle TAGS.
-sub handle_tags
-{
-    define_variable ('am.tags.files', INTERNAL,
-                     qw/$(HEADERS) $(SOURCES) $(TAGS_FILES) $(LISP)
-                        $(am.config-hdr.local.in)/);
-
-    if (rvar('am.tags.files')->value_as_list_recursive
-          || var ('ETAGS_ARGS') || var ('SUBDIRS'))
-      {
-       $output_rules .= &file_contents ('tags', new Automake::Location);
-       set_seen 'TAGS_DEPENDENCIES';
-      }
-    else
-      {
-        reject_var ('TAGS_DEPENDENCIES',
-                   "it doesn't make sense to define 'TAGS_DEPENDENCIES'"
-                   . " without\nsources or 'ETAGS_ARGS'");
-       # Every Makefile must define some sort of TAGS rule.
-       # Otherwise, it would be possible for a top-level "make TAGS"
-       # to fail because some subdirectory failed.  Ditto ctags and
-        # cscope.
-        $output_rules .=
-          "tags TAGS:\n\n" .
-          "ctags CTAGS:\n\n" .
-          "cscope cscopelist:\n\n";
-      }
-}
-
-
 # user_phony_rule ($NAME)
 # -----------------------
 # Return false if rule $NAME does not exist.  Otherwise,
@@ -6788,9 +6758,9 @@ sub generate_makefile ($$)
   handle_man_pages;
   handle_data;
   handle_headers;
+  verbatim ('tags');
   handle_subdirs;
   handle_user_recursion;
-  handle_tags;
   handle_minor_options;
 
   # Must come after invocation of handle_programs, handle_libraries and
diff --git a/lib/am/tags.am b/lib/am/tags.mk
similarity index 62%
rename from lib/am/tags.am
rename to lib/am/tags.mk
index bd7e2c7..aebd8b6 100644
--- a/lib/am/tags.am
+++ b/lib/am/tags.mk
@@ -14,6 +14,22 @@
 ## You should have received a copy of the GNU General Public License
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+# Every Makefile must define some sort of TAGS rule.  Otherwise, it
+# would be possible for a top-level "make TAGS" to fail because some
+# subdirectory failed.  Ditto for ctags and cscope.
+.PHONY: tags TAGS ctags CTAGS cscope cscopelist
+
+am.tags.files = \
+  $(call am.memoize,am.tags.files,$(strip \
+    $(HEADERS) $(SOURCES) $(TAGS_FILES) $(LISP) $(am.config-hdr.local.in)))
+
+# Let's see if we have to actually deal with tags creation.
+ifneq ($(or $(am.tags.files),$(ETAGS_ARGS),$(SUBDIRS)),)
+
+# ---------------------------------- #
+#  Tags-related internal variables.  #
+# ---------------------------------- #
+
 # Use $(sort) rather than $(am.util.uniq) here, because the former is
 # faster on long lists, and we don't care about the order of the list
 # anyway.
@@ -37,75 +53,70 @@ am.tags.subfiles = \
   $(call am.memoize,am.tags.subfiles,$(strip \
     $(foreach d,$(filter-out .,$(SUBDIRS)),$(wildcard $d/TAGS))))
 
-## ---- ##
-## ID.  ##
-## ---- ##
+
+# ---------------------------------- #
+#  ID database (from GNU id-utils).  #
+# ---------------------------------- #
 
 ID: $(am.tags.files)
        mkid -fID $(am.tags.files.unique)
+am.clean.dist.f += ID
 
 
-## ------ ##
-## TAGS.  ##
-## ------ ##
+# -------------------------------- #
+#  GNU Etags and Exuberant ctags.  #
+# -------------------------------- #
 
+CTAGS = ctags
 ETAGS = etags
-.PHONY: TAGS tags
-if %?SUBDIRS%
-AM_RECURSIVE_TARGETS += TAGS
-RECURSIVE_TARGETS += tags-recursive
+
+ifdef SUBDIRS
+AM_RECURSIVE_TARGETS += TAGS CTAGS
+RECURSIVE_TARGETS += tags-recursive ctags-recursive
+ctags: ctags-recursive
 tags: tags-recursive
-else !%?SUBDIRS%
+else
 tags: tags-am
-endif !%?SUBDIRS%
+ctags: ctags-am
+endif
+
 TAGS: tags
+CTAGS: ctags
+.PHONY: TAGS tags CTAGS ctags
 
 tags-am: $(TAGS_DEPENDENCIES) $(am.tags.files)
-## Make sure we have something to run etags on.
-       test -z '$(ETAGS_ARGS)$(am.tags.subfiles)$(am.tags.files.unique)' || { \
-         $(ETAGS) \
-           $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
-           $(foreach 
f,$(am.tags.subfiles),'$(am.tags.include-option)=$(CURDIR)/$f') \
-           $(am.tags.files.unique); \
-       }
-
+ifneq ($(or $(ETAGS_ARGS),$(am.tags.subfiles),$(am.tags.files.unique)),)
+       $(ETAGS) \
+         $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
+         $(foreach 
f,$(am.tags.subfiles),'$(am.tags.include-option)=$(CURDIR)/$f') \
+         $(am.tags.files.unique)
+endif
 
-## --------------- ##
-## vi-style tags.  ##
-## --------------- ##
-
-CTAGS = ctags
-.PHONY: CTAGS ctags
-if %?SUBDIRS%
-AM_RECURSIVE_TARGETS += CTAGS
-RECURSIVE_TARGETS += ctags-recursive
-ctags: ctags-recursive
-else !%?SUBDIRS%
-ctags: ctags-am
-endif !%?SUBDIRS%
-
-CTAGS: ctags
 ctags-am: $(TAGS_DEPENDENCIES) $(am.tags.files)
-## Make sure we have something to run ctags on.
-       test -z "$(CTAGS_ARGS)$(am.tags.files.unique)" \
-         || $(CTAGS) $(CTAGSFLAGS) $(AM_CTAGSFLAGS) $(CTAGS_ARGS) \
-            $(am.tags.files.unique)
+ifneq ($(or $(CTAGS_ARGS),$(am.tags.files.unique)),)
+       $(CTAGS) \
+         $(CTAGSFLAGS) $(AM_CTAGSFLAGS) $(CTAGS_ARGS) \
+         $(am.tags.files.unique)
+endif
 
+am.clean.dist.f += TAGS tags
 
-## --------------- ##
-## "Global tags".  ##
-## --------------- ##
+
+# -------------------- #
+#  GNU "Global tags".  #
+# -------------------- #
 
 .PHONY: GTAGS
 GTAGS:
        cd $(top_srcdir) && gtags -i $(GTAGS_ARGS) '$(abs_top_builddir)'
+am.clean.dist.f += GTAGS GRTAGS GSYMS
 
 
-## ------- ##
-## cscope  ##
-## ------- ##
+# --------- #
+#  Cscope.  #
+# --------- #
 
-if %?TOPDIR_P%
+ifdef am.conf.is-topdir
 CSCOPE = cscope
 .PHONY: cscope clean-cscope
 AM_RECURSIVE_TARGETS += cscope
@@ -115,14 +126,15 @@ cscope: cscope.files
 clean-cscope:
        rm -f cscope.files
 cscope.files: clean-cscope cscopelist
-endif %?TOPDIR_P%
+am.clean.dist.f += cscope.out cscope.in.out cscope.po.out cscope.files
+endif
 
-if %?SUBDIRS%
+ifdef SUBDIRS
 RECURSIVE_TARGETS += cscopelist-recursive
 cscopelist: cscopelist-recursive
-else !%?SUBDIRS%
+else
 cscopelist: cscopelist-am
-endif !%?SUBDIRS%
+endif
 
 cscopelist-am: $(am.tags.files)
        list='$(am.tags.files)'; \
@@ -138,12 +150,4 @@ cscopelist-am: $(am.tags.files)
          fi; \
        done >> $(top_builddir)/cscope.files
 
-
-## ---------- ##
-## Cleaning.  ##
-## ---------- ##
-
-am.clean.dist.f += TAGS ID GTAGS GRTAGS GSYMS GPATH tags
-if %?TOPDIR_P%
-am.clean.dist.f += cscope.out cscope.in.out cscope.po.out cscope.files
-endif %?TOPDIR_P%
+endif # Dealing with tags.
diff --git a/t/location.sh b/t/location.sh
index dab1e33..424904b 100755
--- a/t/location.sh
+++ b/t/location.sh
@@ -32,7 +32,7 @@ if COND2
   lib_LIBRARIES = libfoo.a
 endif
 if COND1
-  bin_PROGRAMS += ctags
+  bin_PROGRAMS += distdir
 endif
 VAR = 1 \
       2 \
@@ -77,9 +77,9 @@ sed 's/^> //' > expected << 'END'
 > Makefile.am:1:   while processing program 'libfoo.a'
 > library.am: ... 'libfoo.a' previously defined here
 > Makefile.am:3:   while processing library 'libfoo.a'
-> tags.am: warning: redefinition of 'ctags' ...
-> program.am: ... 'ctags$(EXEEXT)' previously defined here
-> Makefile.am:6:   while processing program 'ctags'
+> distdir.am: warning: redefinition of 'distdir' ...
+> program.am: ... 'distdir$(EXEEXT)' previously defined here
+> Makefile.am:6:   while processing program 'distdir'
 END
 
 cat expected
diff --git a/t/tags.sh b/t/tags-id.sh
similarity index 78%
rename from t/tags.sh
rename to t/tags-id.sh
index 8f38e6b..9032125 100755
--- a/t/tags.sh
+++ b/t/tags-id.sh
@@ -17,13 +17,30 @@
 # Test for bug reported by Harlan Stenn: the tags target doesn't work
 # when there are only headers in a directory.
 
+required=mkid
 . ./defs || exit 1
 
+echo AC_OUTPUT >> configure.ac
+
 cat > Makefile.am << 'END'
 noinst_HEADERS = iguana.h
+test-id: ID
+       test -f $(srcdir)/iguana.h
+       test -f ID
+check-local: test-id
+END
+
+cat > iguana.h << 'END'
+#define FOO "bar"
+int zap (int x, char y);
 END
 
 $ACLOCAL
+$AUTOCONF
 $AUTOMAKE
 
-grep '^ID:' Makefile.in
+./configure
+$MAKE test-id
+$MAKE distcheck
+
+:
diff --git a/t/tags2.sh b/t/tags2.sh
deleted file mode 100755
index 521d2ef..0000000
--- a/t/tags2.sh
+++ /dev/null
@@ -1,42 +0,0 @@
-#! /bin/sh
-# Copyright (C) 2010-2012 Free Software Foundation, Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# TAGS_DEPENDENCIES only make sense if other tag-worthy things (such as
-# sources) exist.
-
-. ./defs || exit 1
-
-cat >> configure.ac << 'END'
-AC_PROG_CC
-AC_OUTPUT
-END
-
-cat >Makefile.am << 'END'
-TAGS_DEPENDENCIES = foo
-END
-
-$ACLOCAL
-AUTOMAKE_fails
-grep 'define.*TAGS_DEPENDENCIES.*without' stderr
-
-cat >>Makefile.am << 'END'
-bin_PROGRAMS = bar
-END
-
-AUTOMAKE_run
-grep 'define.*TAGS_DEPENDENCIES.*without' stderr && exit 1
-
-:
diff --git a/t/targetclash.sh b/t/targetclash.sh
index 031cbc1..9c71007 100755
--- a/t/targetclash.sh
+++ b/t/targetclash.sh
@@ -23,11 +23,11 @@ AC_PROG_CC
 END
 
 cat > Makefile.am << 'END'
-bin_PROGRAMS = ctags
+bin_PROGRAMS = distdir
 END
 
 $ACLOCAL
 AUTOMAKE_fails -a
-grep 'redefinition.*ctags' stderr
+grep 'redefinition.*distdir' stderr
 
 :
-- 
1.7.12.rc0