kc3-lang/automake/t/remake-timing-bug-pr8365.sh

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• Hash : ffd4ecc9
  Author :
  Date : 2013-05-20T11:23:01
  

  tests: better idiom to override make macro defs on the cmdline
  
  We now do so with a new wrapper shell function 'run_make()', which
  relies on the use of AM_MAKEFLAGS, avoiding the use of the '-e' make
  option.  The use of that option (that causes the environment variables
  to take precedence over the macro definitions in the Makefile) has
  proved to be quite brittle in the past, causing annoying and sometimes
  problematic spurious failures.  This has worsened in some still
  unpublished work going on in development branches.  It's time to solve
  the issue once and for all.
  
  Note that we do not convert all uses of $MAKE in the testsuite right
  away; we might do so in follow-up changes, with leisure, to avoid a
  "patch bomb" effect (this commit is already too much of a bomb itself).
  What we do in this commit is to get rid of all "$MAKE -e" invocations.
  
  We admit that the implementation and feature-set of 'run_make()' are
  far from perfect, but good enough for our current purposes.  We'll
  improve 'run_make()' if and when the need arises.
  
  * syntax-checks.mk (sc_tests_no_make_e): New syntax check, guard against
  the use of "$MAKE -e".
  (syntax_check_rules): Add it.
  (sc_tests_overriding_macros_on_cmdline): Adjust.
  (lint): New, alias for 'maintainer-check', for lazy typists.  Idea
  backported from the 'maint' branch (Automake 1.13a).
  * t/ax/am-test-lib.sh (run_make): New function.  Run $MAKE with the
  given command-line arguments, handling command-line override of variable
  definitions in a smart way (using AM_MAKEFLAGS if a non-GNU make
  implementation is detected to be in use).
  (useless_vpath_rebuild): Adjust to use 'run_make', to avoid a spurious
  maintainer check failure.
  (yl_distcheck): Use 'run_make' rather than bare '$MAKE'.
  (single_quote, append_single_quoted, is_valid_varname): New auxiliary
  function, used, directly or indirectly, by it.
  * Many tests: Adjust to avoid the use of "$MAKE -e", and prefer the
  use of 'run_make' in few other contexts as well, where it makes sense.
  Other minor fixlets while at it.
  
  Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>
  

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• t/remake-timing-bug-pr8365.sh

• #! /bin/sh
  # Copyright (C) 2011-2013 Free Software Foundation, Inc.
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation; either version 2, or (at your option)
  # any later version.
  #
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  
  # Test for automake bug#8365, related to Makefile remake rules.
  # The bug is due to subtle timestamp issues and limitations in
  # make's behaviour, and is very unlikely to be triggered (we have
  # to resort to timestamp edit hacks to consistently expose it); in
  # any account, it is nigh to impossible to trigger it by running
  # make by hand.  Thus, fixing it would not be worth the hassle, but
  # we prefer to keep it exposed anyway.
  
  . test-init.sh
  
  # We'll use calls to stat to get debugging information.
  if stat /dev/null; then stat=stat; else stat=:; fi
  
  cat >> configure.ac << 'END'
  FOOBAR=zardoz
  AC_OUTPUT
  END
  
  : > Makefile.am
  
  $ACLOCAL
  # Run automake *before* autoconf, because we want to ensure that
  # Makefile.in is not newer than configure.
  $AUTOMAKE
  $AUTOCONF
  
  ./configure
  $MAKE Makefile
  # Sanity check.
  $EGREP 'FOOBAR|zardoz' Makefile && fatal_ 'unexpected AC_SUBST in Makefile'
  
  echo 'AC_SUBST([FOOBAR])' >> configure.ac
  
  # Modified configure dependencies must have the same timestamp of
  # config.status and Makefile in order to trigger the bug.
  # We also re-touch config.status, because "touch -r" can truncate
  # timestamps on file systems with sub-second resolutions (see the
  # autoconf manual).  Finally, we also sleep before touching, to ensure
  # that the (possibly truncated) timestamps of config.status etc. are
  # strictly newer than the non-truncated configure timestamp.
  $stat config.status Makefile configure.ac
  $sleep
  touch config.status
  touch -r config.status config.status Makefile configure.ac
  $stat config.status Makefile configure.ac
  
  # Also, the race condition is triggered only when aclocal, automake
  # and aclocal run fast enough to keep the timestamp of the generated
  # aclocal.m4, Makefile.in and configure equal to the timestamp of
  # Makefile & config.status.  To reproduce this race consistently, we
  # need the following hackish wrappers.
  
  cat > aclocal-wrap <<END
  #!/bin/sh
  set -ex
  # aclocal shouldn't use our autoconf wrapper when extracting
  # the races from configure.ac.
  AUTOCONF='$AUTOCONF'; export AUTOCONF
  $ACLOCAL "\$@"
  touch -r config.status aclocal.m4
  $stat aclocal.m4
  END
  
  cat > automake-wrap <<END
  #!/bin/sh
  set -ex
  # automake shouldn't use our autoconf wrapper when extracting
  # the races from configure.ac.
  AUTOCONF='$AUTOCONF'; export AUTOCONF
  $AUTOMAKE "\$@"
  touch -r config.status Makefile.in
  $stat Makefile.in
  END
  
  cat > autoconf-wrap <<END
  #!/bin/sh
  set -ex
  $AUTOCONF "\$@"
  touch -r config.status configure
  $stat configure
  END
  
  chmod a+x aclocal-wrap automake-wrap autoconf-wrap
  
  run_make Makefile \
    ACLOCAL=./aclocal-wrap AUTOMAKE=./automake-wrap AUTOCONF=./autoconf-wrap
  grep '^FOOBAR =' Makefile.in
  grep '^FOOBAR *= *zardoz *$' Makefile
  
  :
  

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