From: Andrew Walrond <andrew@...>
Date: 2009-02-11T09:39:01+09:00
Subject: [ruby-core:21974] Re: ruby 1.9.1 parallel make race

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Andrew Walrond wrote:
>
> And here is another failure which happened as I was typing:
>
>    mkdir -p ../../.ext/common/ripper
>    cp ../.././ext/ripper/lib/ripper/core.rb ../../.ext/common/ripper
>    mkdir: cannot create directory `../../.ext/common/ripper': File exists
>
> I guess this will be easy enough to fix, if it hasn't been already. I 
> could get setup with the latest source repo and attempt a patch if it 
> would be useful; Let me know.
>

Well, not quite as easy as I thought because all the makefiles are 
generated by create_makefile in lib/mkmf.rb. But once I got my head 
around it, one small change to mkmf.rb fixes all the makefiles :)

Here's a patch against 1.9.1-p0 (also attached):

--- ruby-1.9.1-p0/lib/mkmf.rb   2009-01-28 09:23:46.000000000 +0000
+++ ruby-1.9.1-p0-apw/lib/mkmf.rb       2009-02-10 23:21:51.510922231 +0000
@@ -1703,7 +1703,7 @@
       for f in files
        dest = "#{dir}/#{File.basename(f)}"
        mfile.print("install-rb#{sfx}: #{dest}\n")
-        mfile.print("#{dest}: #{f}\n")
+        mfile.print("#{dest}: #{f} #{dir}\n")
         mfile.print("\t$(#{$extout ? 'COPY' : 'INSTALL_DATA'}) ")
        mfile.print("#{fseprepl[f]} $(@D#{sep})\n")
        if defined?($installed_list) and !$extout

(applies successfully against TRUNK also)

Sanity check:

Looking at the Makefile causing the failure above, a typical copy rule is:

    $(RUBYLIBDIR)/ripper/core.rb: $(srcdir)/lib/ripper/core.rb
            $(COPY) $(srcdir)/lib/ripper/core.rb $(@D)

and the corresponding mkdir rule is:

    $(RUBYLIBDIR)/ripper/core.rb: $(srcdir)/lib/ripper/core.rb
            $(COPY) $(srcdir)/lib/ripper/core.rb $(@D)

After my patch, the copy rule becomes:

    $(RUBYLIBDIR)/ripper/core.rb: $(srcdir)/lib/ripper/core.rb 
$(RUBYLIBDIR)/ripper
            $(COPY) $(srcdir)/lib/ripper/core.rb $(@D)

and the race is avoided.

I've done several make -j4 builds using the patch without failure so 
far, so it seems to work OK.

Hope that's useful

Andrew Walrond

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--- ruby-1.9.1-p0/lib/mkmf.rb   2009-01-28 09:23:46.000000000 +0000
+++ ruby-1.9.1-p0-apw/lib/mkmf.rb       2009-02-10 23:21:51.510922231 +0000
@@ -1703,7 +1703,7 @@
       for f in files
        dest = "#{dir}/#{File.basename(f)}"
        mfile.print("install-rb#{sfx}: #{dest}\n")
-        mfile.print("#{dest}: #{f}\n")
+        mfile.print("#{dest}: #{f} #{dir}\n")
         mfile.print("\t$(#{$extout ? 'COPY' : 'INSTALL_DATA'}) ")
        mfile.print("#{fseprepl[f]} $(@D#{sep})\n")
        if defined?($installed_list) and !$extout

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