Ignore non-empty lines which become empty after variable expansion.

Don't choke on invalid pattern rules if we fail during makefile parsing.
Don't dump core if a non-empty command becomes empty after expansion.

4 files changed, 56 insertions, 22 deletions

diff --git a/ChangeLog b/ChangeLog
index bf59080..35f7e9a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+1998-10-13  Paul D. Smith  <psmith@gnu.org>
+
+	* job.c (new_job): If the command list resolves to empty (through
+	variable expansion, for example), stop early rather than running
+	start_waiting_job().
+
+1998-10-12  Andreas Schwab  <schwab@issan.cs.uni-dortmund.de>
+
+	* rule.c (print_rule_data_base): Ignore num_pattern_rules if it is
+	zero.
+
+1998-10-09  Paul D. Smith  <psmith@gnu.org>
+
+	* read.c (read_makefile): Allow non-empty lines to expand to the
+	empty string after variable, etc., expansion, and be ignored.
+
 1998-09-21  Paul D. Smith  <psmith@gnu.org>
 
 	* job.c (construct_command_argv_internal): Only add COMMAND.COM
diff --git a/job.c b/job.c
index fcdd2f1..7a77481 100644
--- a/job.c
+++ b/job.c
@@ -1274,11 +1274,16 @@ new_job (file)
   c->sh_batch_file = NULL;
 
   /* Fetch the first command line to be run.  */
-  job_next_command (c);
-
-  /* The job is now primed.  Start it running.
-     (This will notice if there are in fact no commands.)  */
-  (void)start_waiting_job (c);
+  if (job_next_command (c))
+    /* The job is now primed.  Start it running.  */
+    (void)start_waiting_job (c);
+  else
+    {
+      /* There were no commands (variable expands to empty?).  All done.  */
+      c->file->update_status = 0;
+      notice_finished_file(c->file);
+      free_child (c);
+    }
 
   if (job_slots == 1)
     /* Since there is only one job slot, make things run linearly.
diff --git a/read.c b/read.c
index a677399..242f953 100644
--- a/read.c
+++ b/read.c
@@ -718,8 +718,7 @@ read_makefile (filename, flags)
 	     because there was no preceding target, and the line
 	     might have been usable as a variable definition.
 	     But now it is definitely lossage.  */
-	  fatal (&fileinfo,
-			  "commands commence before first target");
+	  fatal(&fileinfo, "commands commence before first target");
 	}
       else
 	{
@@ -767,12 +766,10 @@ read_makefile (filename, flags)
             {
             case w_eol:
               if (cmdleft != 0)
-                fatal (&fileinfo,
-                                "missing rule before commands");
-              else
-                /* This line contained a variable reference that
-                   expanded to nothing but whitespace.  */
-                continue;
+                fatal(&fileinfo, "missing rule before commands");
+              /* This line contained something but turned out to be nothing
+                 but whitespace (a comment?).  */
+              continue;
 
             case w_colon:
             case w_dcolon:
@@ -835,11 +832,7 @@ read_makefile (filename, flags)
 
               wtype = get_next_mword(lb_next, NULL, &lb_next, &len);
               if (wtype == w_eol)
-                /* There's no need to be ivory-tower about this: check for
-                   one of the most common bugs found in makefiles...  */
-                fatal (&fileinfo, "missing separator%s",
-                       strncmp(lb.buffer, "        ", 8) ? ""
-                       : " (did you mean TAB instead of 8 spaces?)");
+                break;
 
               p2 += strlen(p2);
               *(p2++) = ' ';
@@ -851,6 +844,20 @@ read_makefile (filename, flags)
 
 	  p2 = next_token (variable_buffer);
 
+          /* If the word we're looking at is EOL, see if there's _anything_
+             on the line.  If not, a variable expanded to nothing, so ignore
+             it.  If so, we can't parse this line so punt.  */
+          if (wtype == w_eol)
+            {
+              if (*p2 != '\0')
+                /* There's no need to be ivory-tower about this: check for
+                   one of the most common bugs found in makefiles...  */
+                fatal (&fileinfo, "missing separator%s",
+                       strncmp(lb.buffer, "        ", 8) ? ""
+                       : " (did you mean TAB instead of 8 spaces?)");
+              continue;
+            }
+
           /* Make the colon the end-of-string so we know where to stop
              looking for targets.  */
           *colonp = '\0';
diff --git a/rule.c b/rule.c
index eb4602f..b2b14a1 100644
--- a/rule.c
+++ b/rule.c
@@ -1,5 +1,5 @@
 /* Pattern and suffix rule internals for GNU Make.
-Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+Copyright (C) 1988,89,90,91,92,93, 1998 Free Software Foundation, Inc.
 This file is part of GNU Make.
 
 GNU Make is free software; you can redistribute it and/or modify
@@ -14,7 +14,8 @@ GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with GNU Make; see the file COPYING.  If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
 
 #include "make.h"
 #include "dep.h"
@@ -664,8 +665,13 @@ print_rule_data_base ()
     }
 
   if (num_pattern_rules != rules)
-    fatal (NILF, "BUG: num_pattern_rules wrong!  %u != %u",
-	   num_pattern_rules, rules);
+    {
+      /* This can happen if a fatal error was detected while reading the
+         makefiles and thus count_implicit_rule_limits wasn't called yet.  */
+      if (num_pattern_rules != 0)
+        fatal ("BUG: num_pattern_rules wrong!  %u != %u",
+               num_pattern_rules, rules);
+    }
 
   puts ("\n# Pattern-specific variable values");