Support overriding anchors

In YAML 1.2, anchors can be reused. https://yaml.org/spec/1.2/spec.html#id2786196
yaml · Sep 22, 2021 · 5a5dc9f · 5a5dc9f
1 parent 35f0417
commit 5a5dc9f
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Showing 7 changed files with 6 additions and 21 deletions.
diff --git a/lib/yaml/composer.py b/lib/yaml/composer.py
@@ -70,11 +70,6 @@ def compose_node(self, parent, index):
             return self.anchors[anchor]
         event = self.peek_event()
         anchor = event.anchor
-        if anchor is not None:
-            if anchor in self.anchors:
-                raise ComposerError("found duplicate anchor %r; first occurrence"
-                        % anchor, self.anchors[anchor].start_mark,
-                        "second occurrence", event.start_mark)
         self.descend_resolver(parent, index)
         if self.check_event(ScalarEvent):
             node = self.compose_scalar_node(anchor)

diff --git a/tests/data/duplicate-anchor-1.loader-error b/tests/data/duplicate-anchor-1.loader-error
diff --git a/tests/data/override-anchor-1.code b/tests/data/override-anchor-1.code
@@ -0,0 +1 @@
+(['bar', 'bar', 'baz', 'baz'])
diff --git a/tests/data/override-anchor-1.data b/tests/data/override-anchor-1.data
@@ -0,0 +1,4 @@
+- &foo bar
+- *foo
+- &foo baz
+- *foo
diff --git a/tests/data/override-anchor-2.code b/tests/data/override-anchor-2.code
@@ -0,0 +1 @@
+[1, 2, 3, 4]
diff --git a/tests/data/duplicate-anchor-2.loader-error → tests/data/override-anchor-2.data b/tests/data/duplicate-anchor-2.loader-error → tests/data/override-anchor-2.data
diff --git a/yaml/_yaml.pyx b/yaml/_yaml.pyx
@@ -754,19 +754,6 @@ cdef class CParser:
         elif self.parsed_event.type == YAML_MAPPING_START_EVENT    \
                 and self.parsed_event.data.mapping_start.anchor != NULL:
             anchor = PyUnicode_FromString(self.parsed_event.data.mapping_start.anchor)
-        if anchor is not None:
-            if anchor in self.anchors:
-                mark = Mark(self.stream_name,
-                        self.parsed_event.start_mark.index,
-                        self.parsed_event.start_mark.line,
-                        self.parsed_event.start_mark.column,
-                        None, None)
-                if PY_MAJOR_VERSION < 3:
-                    raise ComposerError("found duplicate anchor; first occurrence",
-                            self.anchors[anchor].start_mark, "second occurrence", mark)
-                else:
-                    raise ComposerError(u"found duplicate anchor; first occurrence",
-                            self.anchors[anchor].start_mark, u"second occurrence", mark)
         self.descend_resolver(parent, index)
         if self.parsed_event.type == YAML_SCALAR_EVENT:
             node = self._compose_scalar_node(anchor)