Improve the configuration cache accuracy

waflib/Configure.py

@@ -524,7 +524,7 @@ def run_build(self, *k, **kw):
 	Though this function returns *0* by default, the build may set an attribute named *retval* on the
 	build context object to return a particular value. See :py:func:`waflib.Tools.c_config.test_exec_fun` for example.
 
-	This function also provides a limited cache. To use it, provide the following option::
+	This function also features a cache which can be enabled by the following option::
 
 		def options(opt):
 			opt.add_option('--confcache', dest='confcache', default=0,
@@ -535,10 +535,22 @@ def run_build(self, *k, **kw):
 		$ waf configure --confcache
 
 	"""
-	lst = [str(v) for (p, v) in kw.items() if p != 'env']
-	h = Utils.h_list(lst)
+	buf = []
+	for key in sorted(kw.keys()):
+		if key != 'env':
+			v = kw[key]
+			if hasattr(v, '__call__'):
+				buf.append(Utils.h_fun(v))
+			else:
+				buf.append(str(v))
+	h = Utils.h_list(buf)
 	dir = self.bldnode.abspath() + os.sep + (not Utils.is_win32 and '.' or '') + 'conf_check_' + Utils.to_hex(h)
 
+	cachemode = kw.get('confcache', getattr(Options.options, 'confcache', None))
+
+	if not cachemode and os.path.exists(dir):
+		shutil.rmtree(dir)
+
 	try:
 		os.makedirs(dir)
 	except OSError:
@@ -549,7 +561,6 @@ def run_build(self, *k, **kw):
 	except OSError:
 		self.fatal('cannot use the configuration test folder %r' % dir)
 
-	cachemode = getattr(Options.options, 'confcache', None)
 	if cachemode == 1:
 		try:
 			proj = ConfigSet.ConfigSet(os.path.join(dir, 'cache_run_build'))
@@ -589,7 +600,7 @@ def run_build(self, *k, **kw):
 		else:
 			ret = getattr(bld, 'retval', 0)
 	finally:
-		if cachemode == 1:
+		if cachemode:
 			# cache the results each time
 			proj = ConfigSet.ConfigSet()
 			proj['cache_run_build'] = ret

waflib/Tools/c_tests.py

@@ -224,6 +224,7 @@ def check_endianness(self):
 	def check_msg(self):
 		return tmp[0]
 	self.check(fragment=ENDIAN_FRAGMENT, features='c grep_for_endianness',
-		msg='Checking for endianness', define='ENDIANNESS', tmp=tmp, okmsg=check_msg)
+		msg='Checking for endianness', define='ENDIANNESS', tmp=tmp,
+		okmsg=check_msg, confcache=None)
 	return tmp[0]