Fix resolved values in case of failure

When the value cannot be resolved usually the original value is
returned. However if it contains `%` signs there will be an escape step
and that escaped value is returned.
That makes it impossible to have values which can only later be
resolved, like `cd %(startdir)s` in extensions which would become
`cd %%(startdir)s` on the first resolve-attempt.

easybuild/framework/easyconfig/easyconfig.py

@@ -2026,12 +2026,14 @@ def resolve_template(value, tmpl_dict):
         # '%(name)s' -> '%(name)s'
         # '%%(name)s' -> '%%(name)s'
         if '%' in value:
+            orig_value = value
             value = re.sub(re.compile(r'(%)(?!%*\(\w+\)s)'), r'\1\1', value)
 
             try:
                 value = value % tmpl_dict
             except KeyError:
                 _log.warning("Unable to resolve template value %s with dict %s", value, tmpl_dict)
+                value = orig_value  # Undo "%"-escaping
     else:
         # this block deals with references to objects and returns other references
         # for reading this is ok, but for self['x'] = {}

test/framework/easyconfig.py

@@ -3663,6 +3663,9 @@ def test_resolve_template(self):
             ('%%(name)s', '%(name)s'),
             ('%%%(name)s', '%FooBar'),
             ('%%%%(name)s', '%%(name)s'),
+            # It doesn't matter what is resolved
+            ('%%(invalid)s', '%(invalid)s'),
+            ('%%%%(invalid)s', '%%(invalid)s'),
         )
         for value, expected in values:
             self.assertEqual(resolve_template(value, tmpl_dict), expected)
@@ -3671,6 +3674,10 @@ def test_resolve_template(self):
             expected += ' FooBar'
             self.assertEqual(resolve_template(value, tmpl_dict), expected)
 
+        # On unknown values the value is returned unchanged
+        for value in ('%(invalid)s', '%(name)s %(invalid)s', '%%%(invalid)s', '% %(invalid)s', '%s %(invalid)s'):
+            self.assertEqual(resolve_template(value, tmpl_dict), value)
+
     def test_det_subtoolchain_version(self):
         """Test det_subtoolchain_version function"""
         _, all_tc_classes = search_toolchain('')