The code here is looking for lines including *.Po dependency files in output Makefiles. It never caused a problem because if am__include wasn't set in the output file, then there would be unlikely to be any lines picked up by the sed expression looking for the include lines.
I found this really by accident. I've been patching automake to see if I can make it output plain Makefiles. I've arranged for many autoconf output variables to be in a Makefile include file, so a line like "am__include = include" was not in the Makefile, but in the include file. However, I found that it would get past this check anyway. am__include seems only to be set as a make variable so that config.status can read it. Otherwise you would expect it to be declared with _AM_SUBST_NOTMAKE. automake is passing config.status a note via Makefile.in; there aren't any other ways for them to communicate (although an unusual way of doing it would be for automake to generate files which are source'd or m4_include'd from configure.ac). On Thu, Apr 11, 2013 at 7:45 PM, Nick Bowler <nbow...@elliptictech.com> wrote: > On 2013-04-11 19:12 +0100, Gavin Smith wrote: >> (I hope I have prepared this patch properly.) >> >> Add missing '$' for variable expansion in depout.m4 >> >> * m4/depout.m4: "am__include" appeared where "$am__include" was meant. >> >> diff --git a/m4/depout.m4 b/m4/depout.m4 >> index 880a597..c79d04b 100644 >> --- a/m4/depout.m4 >> +++ b/m4/depout.m4 >> @@ -40,7 +40,7 @@ AC_DEFUN([_AM_OUTPUT_DEPENDENCY_COMMANDS], >> DEPDIR=`sed -n 's/^DEPDIR = //p' < "$mf"` >> test -z "$DEPDIR" && continue >> am__include=`sed -n 's/^am__include = //p' < "$mf"` >> - test -z "am__include" && continue >> + test -z "$am__include" && continue > > Well-spotted! This definitely looks like a mistake. How did you > find this? > > The test appears to have been defective ever since it was introduced > almost 10 years ago. At this point, it may be better to simply remove > the dead code entirely unless this is known to fix a real problem. > > Cheers, > -- > Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)
