Testsuite coverage for 'Caching Results' section.

[Ralf Wildenhues]

This is not for 2.66, even if it gets done before the release.

The testsuite coverage for documented macros leaves room for
improvement.  This patch is the result of going through the 'Caching
Results' section of the manual and trying to let each statement, where
it made sense, have some form of coverage.

I noted that the fact that you may override cache variables loaded from
a cache file with configure command-line options.  I've used this
behavior myself a few times, I think it's worth documenting.  (Note the
*_env_* cache variables are an exception here, you cannot override them
this way; the environment variables they store are precious, so
overriding them won't work either, on purpose.)

OK?

If we make one of these patches each weekend, covering three more
documented macros, or one section in the manual, then we may achieve
full coverage within a year.  Whew.

Thanks,
Ralf

    Testsuite coverage for AC_CACHE_VAL and caching semantics.
    
    * tests/base.at (AC_CACHE_CHECK): Extend test.
    (AC_CACHE_LOAD): New test.
    * tests/torture.at (Configuring subdirectories): Also test
    --config-cache with AC_CONFIG_SUBDIRS.
    * doc/autoconf.texi (Caching Results): Annotate code snippets
    which are tested in the test suite.
    (Cache Files): Documented cache variables may be used on the
    configure command line to override individual entries in the
    cache file.

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 889f9a3..43261e2 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -9552,6 +9552,7 @@ It is common to find buggy macros using 
@code{AC_CACHE_VAL} or
 instance, the following macro is broken:
 
 @example
address@hidden If you change this example, adjust tests/base.at:AC_CACHE_CHECK.
 @group
 AC_DEFUN([AC_SHELL_TRUE],
 [AC_CACHE_CHECK([whether true(1) works], [my_cv_shell_true_works],
@@ -9571,6 +9572,7 @@ This fails if the cache is enabled: the second time this 
macro is run,
 is:
 
 @example
address@hidden If you change this example, adjust tests/base.at:AC_CACHE_CHECK.
 @group
 AC_DEFUN([AC_SHELL_TRUE],
 [AC_CACHE_CHECK([whether true(1) works], [my_cv_shell_true_works],
@@ -9650,7 +9652,8 @@ documented semantics.
 A cache file is a shell script that caches the results of configure
 tests run on one system so they can be shared between configure scripts
 and configure runs.  It is not useful on other systems.  If its contents
-are invalid for some reason, the user may delete or edit it.
+are invalid for some reason, the user may delete or edit it, or override
+documented cache variables on the @command{configure} command line.
 
 By default, @command{configure} uses no cache file,
 to avoid problems caused by accidental
diff --git a/tests/base.at b/tests/base.at
index 5ce3e89..9d071e7 100644
--- a/tests/base.at
+++ b/tests/base.at
@@ -228,19 +228,39 @@ AT_CLEANUP
 
 AT_SETUP([AC_CACHE_CHECK])
 
+# Don't let a config.site file affect this test.
+AS_UNSET([CONFIG_SITE])
+
 AT_DATA([configure.ac],
 [[AC_INIT
 # m4_define([ac_nothing], [ac_cv_absolutely_nothing])
 AC_CACHE_CHECK([for nothing],
               [ac_nothing],
               [ac_nothing=found])
+
+AC_MSG_CHECKING([for some other variable])
+commands_to_set_it_was_run=false
+AC_CACHE_VAL([my_cv_variable], [
+# FOO
+commands_to_set_it_was_run=true
+my_cv_variable=true
+])
+AC_MSG_RESULT([$my_cv_variable])
+
+# Ensure that the result is available at this point.
+if test ${my_cv_variable+set} != set; then
+  AC_MSG_ERROR([AC@&@&address@hidden@_CACHE_VAL did not ensure that the cache 
variable was set])
+fi
+
+# AC_CACHE_SAVE should be enough here, no need for AC_OUTPUT.
+AC_CACHE_SAVE
 ]])
 
 AT_CHECK_AUTOCONF([], [], [], [stderr])
 AT_CHECK([grep 'must contain _cv_ to be cached' stderr], [], [ignore])
 
 # Do not warn about defines:
-sed 's/^# //' configure.ac > t
+sed 's/^# m4_define/m4_define/' configure.ac > t
 mv -f t configure.ac
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE([-q])
@@ -250,6 +270,140 @@ mv -f t configure.ac
 AT_CHECK_AUTOCONF
 AT_CHECK_CONFIGURE([-q])
 
+# Print a message saying that the result was cached, iff it was cached.
+AT_CHECK_CONFIGURE([], [], [stdout])
+AT_CHECK([grep 'cached' stdout], [1])
+AT_CHECK_CONFIGURE([my_cv_variable='yes it is set'], [], [stdout])
+AT_CHECK([grep 'cached.*yes it is set' stdout], [], [ignore])
+
+# --cache-file is honored and has caching semantics.
+AT_CHECK_CONFIGURE([--cache-file=foobar.cache], [], [stdout])
+AT_CHECK([grep 'cached' stdout], [1])
+AT_CHECK([test ! -f config.cache])
+AT_CHECK([grep 'my_cv_variable.*true' foobar.cache], [], [ignore])
+AT_CHECK_CONFIGURE([--cache-file=foobar.cache], [], [stdout])
+AT_CHECK([grep 'some other variable.*cached.*true' stdout], [], [ignore])
+
+# A setting on the command line overrides the cache.
+AT_CHECK_CONFIGURE([--cache-file=foobar.cache my_cv_variable='override'], [], 
[stdout])
+AT_CHECK([grep 'cached.*override' stdout], [], [ignore])
+AT_CHECK([grep 'my_cv_variable.*override' foobar.cache], [], [ignore])
+
+# Values containing braces need special internal treatment.
+AT_CHECK_CONFIGURE([-C ac_cv_nothing='{' my_cv_variable='contains } brace'],
+                  [], [stdout])
+AT_CHECK([grep 'ac_cv_nothing.*{' config.cache], [], [ignore])
+AT_CHECK([grep 'my_cv_variable.*contains } brace' config.cache], [], [ignore])
+AT_CHECK_CONFIGURE([-C], [], [stdout])
+AT_CHECK([grep 'nothing.*{' stdout], [], [ignore])
+AT_CHECK([grep 'some other variable.*contains } brace' stdout], [], [ignore])
+rm -f config.cache
+
+# Diagnose common side-effects that are errors in COMMANDS-TO-SET-IT:
+sed 's/^# FOO/AC_DEFINE([some-define], [1], [oooh.])/' configure.ac > t
+mv -f t configure.ac
+AT_CHECK_AUTOCONF([], [], [], [stderr])
+AT_CHECK([grep 'suspicious.*AC_DEFINE' stderr], [], [ignore])
+
+sed 's/^AC_DEFINE.*/AC_SUBST([some_substitution], [oooh.])/' configure.ac > t
+mv -f t configure.ac
+AT_CHECK_AUTOCONF([], [], [], [stderr])
+AT_CHECK([grep 'suspicious.*AC_SUBST' stderr], [], [ignore])
+
+# Ensure the examples from the manual work as intended.
+# Taken from autoconf.texi:Caching Results
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_DEFUN([AC_SHELL_TRUE],
+[AC_CACHE_CHECK([whether true(1) works], [my_cv_shell_true_works],
+                [my_cv_shell_true_works=no
+                 (true) 2>/dev/null && my_cv_shell_true_works=yes
+                 if test "x$my_cv_shell_true_works" = xyes; then
+                   AC_DEFINE([TRUE_WORKS], [1],
+                             [Define if `true(1)' works properly.])
+                 fi])
+])
+AC_SHELL_TRUE
+]])
+AT_CHECK_AUTOCONF([-Werror], [1], [], [stderr])
+AT_CHECK([grep 'suspicious.*AC_DEFINE' stderr], [], [ignore])
+
+# Taken from autoconf.texi:Caching Results
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_DEFUN([AC_SHELL_TRUE],
+[AC_CACHE_CHECK([whether true(1) works], [my_cv_shell_true_works],
+                [my_cv_shell_true_works=no
+                 (true) 2>/dev/null && my_cv_shell_true_works=yes])
+ if test "x$my_cv_shell_true_works" = xyes; then
+   AC_DEFINE([TRUE_WORKS], [1],
+             [Define if `true(1)' works properly.])
+ fi
+])
+AC_SHELL_TRUE
+AC_OUTPUT
+]])
+AT_CHECK_AUTOCONF([-Werror])
+AT_CHECK_CONFIGURE([-C], [], [stdout])
+AT_CHECK([grep my_cv_shell_true_works config.cache], [], [ignore])
+AT_CHECK([grep 'true.*works.*yes' stdout], [], [ignore])
+
+AT_CHECK_CONFIGURE([--config-cache], [], [stdout])
+AT_CHECK([grep 'true.*works.*cached.*yes' stdout], [], [ignore])
+
+# config.status only pays attention to the cache file with --recheck.
+AT_CHECK([./config.status], [], [stdout])
+AT_CHECK([grep cache stdout], [1])
+AT_CHECK([./config.status --recheck], [], [stdout])
+AT_CHECK([grep cache stdout], [0], [ignore])
+
+# By default, configure uses no cache file, neither loading nor updating it.
+: > a-stamp-file
+AT_CHECK_CONFIGURE([], [], [stdout])
+AT_CHECK([grep cache stdout], [1])
+AT_CHECK([LC_ALL=C ls -t config.cache a-stamp-file | sed 1q | grep 
config.cache], [1])
+
+# config.site can specify a site-wide cache, accumulating information.
+AT_DATA([config.site],
+[[cache_file=sitecache
+]])
+AT_DATA([sitecache],
+[[my_cv_some_preset_cache_var=yes
+]])
+CONFIG_SITE=config.site
+export CONFIG_SITE
+AT_CHECK_CONFIGURE
+AT_CHECK([grep my_cv_some_preset_cache_var sitecache], [], [ignore])
+AT_CHECK([grep my_cv_shell_true_works sitecache], [], [ignore])
+AT_CHECK_CONFIGURE([], [], [stdout])
+AT_CHECK([grep 'whether true.*works.*cached' stdout], [], [ignore])
+
+AT_CLEANUP
+
+
+## --------------- ##
+## AC_CACHE_LOAD.  ##
+## --------------- ##
+
+# Test AC_CACHE_LOAD.
+
+AT_SETUP([AC_CACHE_LOAD])
+
+AT_DATA([configure.ac],
+[[AC_INIT
+$some_test_code
+AC_CACHE_LOAD
+AC_MSG_NOTICE([some_cv_variable is $some_cv_variable])
+AC_OUTPUT
+]])
+AT_CHECK_AUTOCONF
+AS_UNSET([some_test_code])
+AT_DATA([new-cache],
+[[some_cv_variable=value-from-new-cache
+]])
+AT_CHECK_CONFIGURE([some_test_code='eval cache_file=new-cache'], [], [stdout])
+AT_CHECK([grep 'some_cv_variable.*value-from-new-cache' stdout], [], [ignore])
+
 AT_CLEANUP
 
 
diff --git a/tests/torture.at b/tests/torture.at
index 82994af..6909c54 100644
--- a/tests/torture.at
+++ b/tests/torture.at
@@ -1433,6 +1433,11 @@ AT_CHECK([cd builddir && ../configure $configure_options 
--silent], 0, [])
 AT_CHECK([cd builddir && ./config.status --recheck], 0, [stdout])
 AT_CHECK([grep 'creating \./config.status' stdout], 0, [ignore])
 
+# --cache-file is adjusted for subdirectories, so the cache is shared.
+AT_CHECK([cd builddir && ../configure $configure_options --config-cache],
+        [], [stdout])
+AT_CHECK([grep 'loading .*\.\./config.cache' stdout], [], [ignore])
+
 # Make sure we can run autoreconf on a subdirectory
 rm -f configure configure.in
 AT_CHECK([autoreconf inner], [], [], [ignore])