[PATCH] {maint} parallel-tests: reimplement fix for bug#11791

[Stefano Lattarini]

* lib/am/check.am: Here.  The new implementation is shorter, slightly
more efficient (requiring less forks), less brittle in the face of
signals or unexpected interruptions in the make process, and should
also be easier to merge in the 'ng/master' branch (as of now, due to
the difficulties in merging our previous version of the fix in the
'ng/master' codebase, Automake-NG still lacks a fix for bug#11791).

Signed-off-by: Stefano Lattarini <address@hidden>
---

 I plan to push this by this evening.

 Regards,
   Stefano

 lib/am/check.am |   38 +++++++++++++++-----------------------
 1 file changed, 15 insertions(+), 23 deletions(-)

diff --git a/lib/am/check.am b/lib/am/check.am
index 19a803f..e414a90 100644
--- a/lib/am/check.am
+++ b/lib/am/check.am
@@ -240,6 +240,12 @@ am__set_TESTS_bases = \
        rm -f $< $@
        $(MAKE) $(AM_MAKEFLAGS) $<
 
+# Leading 'am--fnord' is there to ensure the list of targets does not
+# exand to empty, as could happen e.g. with make check TESTS=''.
+am--fnord $(TEST_LOGS) $(TEST_LOGS:.log=.trs): $(am__force_recheck)
+am--force-recheck:
+       @:
+
 $(TEST_SUITE_LOG): $(TEST_LOGS)
        @$(am__set_TESTS_bases); \
 ## Helper shell function, tells whether a path refers to an existing,
@@ -431,11 +437,10 @@ recheck: all %CHECK_DEPS%
        bases=`for i in $$bases; do echo $$i; done \
                 | $(am__list_recheck_tests)` || exit 1; \
        log_list=`for i in $$bases; do echo $$i.log; done`; \
-       trs_list=`for i in $$bases; do echo $$i.trs; done`; \
 ## Remove newlines and normalize whitespace.  Trailing (and possibly
 ## leading) whitespace is known to cause segmentation faults on
 ## Solaris 10 XPG4 make.
-       log_list=`echo $$log_list`; trs_list=`echo $$trs_list`; \
+       log_list=`echo $$log_list`; \
 ## Move the '.log' and '.trs' files associated with the tests to be
 ## re-run out of the way, so that those tests will be re-run by the
 ## "make test-suite.log" recursive invocation below.
@@ -445,27 +450,14 @@ recheck: all %CHECK_DEPS%
 ##     we must ensure that any '.log' and '.trs' file referring to such
 ##     test are preserved, so that future "make recheck" invocations
 ##     will still try to re-compile and re-run it (automake bug#11791).
-## The extra contortions below cater to such requirements.
-       am_backupdir=.am-recheck; \
-       if $(am__make_dryrun); then :; else \
-         if test -n "$$trs_list$$log_list"; then \
-           { test ! -d $$am_backupdir || rm -rf $$am_backupdir; } \
-             && $(MKDIR_P) $$am_backupdir || exit 1; \
-           test -z "$$log_list" \
-             || mv -f $$log_list $$am_backupdir 2>/dev/null; \
-           test -z "$$trs_list" \
-             || mv -f $$trs_list $$am_backupdir 2>/dev/null; \
-         fi; \
-       fi; \
-       $(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) TEST_LOGS="$$log_list"; \
-       st=$$?; \
-       if $(am__make_dryrun) || test ! -d $$am_backupdir; then :; else \
-         for f in $$log_list $$trs_list; do \
-           test -f $$f || mv $$am_backupdir/$$f . || exit 1; \
-         done; \
-         rm -rf $$am_backupdir || exit 1; \
-       fi; \
-       exit $$st;
+## The tricky recusrive make invocation below should cater to such
+## requirements.
+       $(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) \
+               am__force_recheck=am--force-recheck \
+               TEST_LOGS="$$log_list"; \
+## Be sure to exit with the proper exit status (automake bug#9245).  See
+## comments in the recipe of $(TEST_SUITE_LOG) above for more information.
+       exit $$?
 
 AM_RECURSIVE_TARGETS += check recheck
 
-- 
1.7.9.5