Path: utzoo!utgpu!watmath!uunet!tut.cis.ohio-state.edu!ucbvax!agate!apple!bionet!ames!fxgrp!news
From: grady@fxgrp.fx.com (Steven Grady)
Newsgroups: gnu.utils.bug
Subject: make 3.55 infinite loop
Message-ID: <1989Aug31.014333.18904@fxgrp.fx.com>
Date: 31 Aug 89 01:43:33 GMT
Reply-To: grady@fxgrp.fx.com (Steven Grady)
Organization: FXDevelopment, Mountain View, CA
Lines: 59

It seems like the new feature that a production that has commands
but no dependencies should always be executed is a mistake.  I believe
this should only be the case if it is a phony target.  If it's a real
file, then a valid interpretation of having no dependencies is that
this is the set of commands to do to _create_ the file.  If the file
exists, no commands need to run.

I'm not sure I am right about this, however.  If you are still interested,
keep reading -- I'll describe the problem I'm having in detail.

I have a makefile system that is kind of complicated.  I include
a file called $(DEPENDENCIES), which is in an architecture-dependent
subdirectory.  In this case, I'm running the program on a sun3.
$(DEPENDENCIES) (in this case, "sun3/Dependencies") has a production
to create it from the "Dependencies" file in the current directory.
This "Dependencies" file is modified by mkmf.  Furthermore, if
the "Dependencies" file doesn't exist (ie the first time you run
the make), it will be copied from a template file (in my case,
a file called "/usr/aws/etc/GnuMake/DependTmpl").

The idea is that if you do a "gnumake depend", the "Dependencies" file 
gets created, then updated.  If you then do a "gnumake" (on a sun3),
the "sun3/Dependencies" file depends on "Dependencies", so it gets
updated.  This new "sun3/Dependencies" file is then included.

This all worked fine until 3.55.  Under 3.55, if I say "gnumake",
it starts going into an infinite loop, saying the following:
  cp /usr/aws/etc/GnuMake/DependTmpl Dependencies
  chmod ug+w Dependencies
  gnumake depend
  cp /usr/aws/etc/GnuMake/DependTmpl Dependencies
  chmod ug+w Dependencies
  gnumake depend
  ...

When I run it with "-d", here is the beginning of the output:
  Reading makefiles...
  Updating makefiles....
    Considering target file `sun3/Dependencies'.
     Considering target file `Dependencies'.
      Finished dependencies of target file `Dependencies'.
     Target `Dependencies' has commands but no dependencies.
     Must remake target `Dependencies'.

Here is the relevant rule:
$(DEPENDFILE):
        cp $(MAKEDIR)/DependTmpl $(DEPENDFILE)
        chmod ug+w $(DEPENDFILE)
        $(MAKE) depend

What's happening is that the file gets copied (since it has commands
but no dependencies), then gnumake gets re-invoked.  It then runs the
same rules, causing gnumake to be re-invoked, etc.

	Steven
	...!ucbvax!grady
	grady@postgres.berkeley.edu

"Guards, beat this man brutally for daring to try to confuse me!"