use SYSTEM constant for dependency that uses system toolchain in dumped easyconfig

easybuild/framework/easyconfig/easyconfig.py

@@ -50,7 +50,7 @@
 import easybuild.tools.filetools as filetools
 from easybuild.base import fancylogger
 from easybuild.framework.easyconfig import MANDATORY
-from easybuild.framework.easyconfig.constants import EXTERNAL_MODULE_MARKER
+from easybuild.framework.easyconfig.constants import EASYCONFIG_CONSTANTS, EXTERNAL_MODULE_MARKER
 from easybuild.framework.easyconfig.default import DEFAULT_CONFIG
 from easybuild.framework.easyconfig.format.convert import Dependency
 from easybuild.framework.easyconfig.format.format import DEPENDENCY_PARAMETERS
@@ -1589,7 +1589,7 @@ def _parse_dependency(self, dep, hidden=False, build_only=False):
 
         # (true) boolean value simply indicates that a system toolchain is used
         elif isinstance(tc_spec, bool) and tc_spec:
-            tc = {'name': SYSTEM_TOOLCHAIN_NAME, 'version': ''}
+            tc = EASYCONFIG_CONSTANTS['SYSTEM'][0]
 
         # two-element list/tuple value indicates custom toolchain specification
         elif isinstance(tc_spec, (list, tuple,)):

easybuild/framework/easyconfig/format/one.py

@@ -76,16 +76,19 @@ def dump_dependency(dep, toolchain, toolchain_hierarchy=None):
     else:
         # minimal spec: (name, version)
         tup = (dep['name'], dep['version'])
+        res = None
         if all(dep['toolchain'] != subtoolchain for subtoolchain in toolchain_hierarchy):
             if dep[SYSTEM_TOOLCHAIN_NAME]:
-                tup += (dep['versionsuffix'], True)
+                # use SYSTEM constant to indicate that system toolchain should be used for this dependency
+                res = re.sub(r'\)$', ', SYSTEM)', str(tup + (dep['versionsuffix'],)))
             else:
                 tup += (dep['versionsuffix'], (dep['toolchain']['name'], dep['toolchain']['version']))
 
         elif dep['versionsuffix']:
             tup += (dep['versionsuffix'],)
 
-        res = str(tup)
+        if res is None:
+            res = str(tup)
     return res
 
 

test/framework/easyconfig.py

@@ -2094,6 +2094,42 @@ def test_dump(self):
                 if param in ec:
                     self.assertEqual(ec[param], dumped_ec[param])
 
+        ec_txt = textwrap.dedent("""
+            easyblock = 'EB_toy'
+
+            name = 'foo'
+            version = '0.0.1'
+
+            toolchain = {'name': 'GCC', 'version': '4.6.3'}
+
+            homepage = 'http://foo.com/'
+            description = "foo description"
+
+            sources = [SOURCE_TAR_GZ]
+            source_urls = ["http://example.com"]
+
+            dependencies = [
+                ('toy', '0.0', '', True),
+                ('GCC', '4.9.2', '', SYSTEM),
+            ]
+
+            moduleclass = 'tools'
+        """)
+        test_ec = os.path.join(self.test_prefix, 'test.eb')
+        write_file(test_ec, ec_txt)
+        ec = EasyConfig(test_ec)
+
+        # verify whether SYSTEM constant is used for dependency that uses system toolchain in dumped easyconfig
+        dumped_ec = os.path.join(self.test_prefix, 'dumped.eb')
+        ec.dump(dumped_ec)
+        dumped_ec_txt = read_file(dumped_ec)
+        patterns = [
+            "('toy', '0.0', '', SYSTEM)",
+            "('GCC', '4.9.2', '', SYSTEM)",
+        ]
+        for pattern in patterns:
+            self.assertTrue(pattern in dumped_ec_txt, "Pattern '%s' should be found in: %s" % (pattern, dumped_ec_txt))
+
     def test_toolchain_hierarchy_aware_dump(self):
         """Test that EasyConfig's dump() method is aware of the toolchain hierarchy."""
         test_ecs_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')