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.

1 files changed, 20 insertions, 13 deletions

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';