Template.has() should be passed ignore_empty=False by default.

**Breaking change**; closes #51.

CHANGELOG

@@ -1,5 +1,8 @@
 v0.4 (unreleased):
 
+- Template.has() is now passed 'ignore_empty=False' by default instead of True.
+  This fixes a bug when adding parameters to templates with empty fields, and
+  is a breaking change if you rely on the default behavior.
 - The 'matches' argument of Wikicode's filter methods now accepts a function
   (taking one argument, a Node, and returning a bool) in addition to a regex.
 - Wikicode.matches() now accepts a tuple of strings/Wikicode objects instead of

docs/changelog.rst

@@ -7,6 +7,10 @@ v0.4
 Unreleased
 (`changes <https://github.com/earwig/mwparserfromhell/compare/v0.3.2...develop>`__):
 
+- :py:meth:`.Template.has` is now passed *ignore_empty=False* by default
+  instead of *True*. This fixes a bug when adding parameters to templates with
+  empty fields, **and is a breaking change if you rely on the default
+  behavior.**
 - The *matches* argument of :py:class:`Wikicode's <.Wikicode>`
   :py:meth:`.filter` methods now accepts a function (taking one argument, a
   :py:class:`.Node`, and returning a bool) in addition to a regex.

mwparserfromhell/nodes/template.py

@@ -174,7 +174,7 @@ class Template(Node):
     def name(self, value):
         self._name = parse_anything(value)
 
-    def has(self, name, ignore_empty=True):
+    def has(self, name, ignore_empty=False):
         """Return ``True`` if any parameter in the template is named *name*.
 
         With *ignore_empty*, ``False`` will be returned even if the template
@@ -190,7 +190,7 @@ class Template(Node):
                 return True
         return False
 
-    has_param = lambda self, name, ignore_empty=True: \
+    has_param = lambda self, name, ignore_empty=False: \
                 self.has(name, ignore_empty)
     has_param.__doc__ = "Alias for :py:meth:`has`."
 

tests/test_template.py

@@ -123,15 +123,15 @@ class TestTemplate(TreeEqualityTestCase):
         node3 = Template(wraptext("foo"),
                          [pgenh("1", "a"), pgens("b", "c"), pgens("1", "d")])
         node4 = Template(wraptext("foo"), [pgenh("1", "a"), pgens("b", " ")])
-        self.assertFalse(node1.has("foobar"))
-        self.assertTrue(node2.has(1))
-        self.assertTrue(node2.has("abc"))
-        self.assertFalse(node2.has("def"))
-        self.assertTrue(node3.has("1"))
-        self.assertTrue(node3.has(" b "))
-        self.assertFalse(node4.has("b"))
-        self.assertTrue(node3.has("b", False))
+        self.assertFalse(node1.has("foobar", False))
+        self.assertTrue(node2.has(1, False))
+        self.assertTrue(node2.has("abc", False))
+        self.assertFalse(node2.has("def", False))
+        self.assertTrue(node3.has("1", False))
+        self.assertTrue(node3.has(" b ", False))
         self.assertTrue(node4.has("b", False))
+        self.assertTrue(node3.has("b", True))
+        self.assertFalse(node4.has("b", True))
 
     def test_get(self):
         """test Template.get()"""
@@ -223,6 +223,7 @@ class TestTemplate(TreeEqualityTestCase):
                                           pgenh("1", "c"), pgenh("2", "d")])
         node40 = Template(wraptext("a"), [pgens("b", "c"), pgens("d", "e"),
                                           pgens("f", "g")])
+        node41 = Template(wraptext("a"), [pgenh("1", "")])
 
         node1.add("e", "f", showkey=True)
         node2.add(2, "g", showkey=False)
@@ -266,6 +267,7 @@ class TestTemplate(TreeEqualityTestCase):
         node38.add("1", "e")
         node39.add("1", "e")
         node40.add("d", "h", before="b")
+        node41.add(1, "b")
 
         self.assertEqual("{{a|b=c|d|e=f}}", node1)
         self.assertEqual("{{a|b=c|d|g}}", node2)
@@ -312,6 +314,7 @@ class TestTemplate(TreeEqualityTestCase):
         self.assertEqual("{{a|1=e|x=y|2=d}}", node38)
         self.assertEqual("{{a|x=y|e|d}}", node39)
         self.assertEqual("{{a|b=c|d=h|f=g}}", node40)
+        self.assertEqual("{{a|b}}", node41)
 
     def test_remove(self):
         """test Template.remove()"""