data: Add Metadata.report_links() method.

This is just a variant of get_links() that eats TypeError.
Higher-level reporting code often wants it.

conservancy_beancount/data.py

@@ -252,6 +252,19 @@ class Metadata(MutableMapping[MetaKey, MetaValue]):
                 key, type(value).__name__,
             ))
 
+    def report_links(self, key: MetaKey) -> Sequence[str]:
+        """Return a sequence of link strings under the named metadata key
+
+        get_links raises a TypeError if the metadata is not a string.
+        This method simply returns the empty sequence.
+        Validation code (like in the plugin) usually uses get_links()
+        while reporting code uses report_links().
+        """
+        try:
+            return self.get_links(key)
+        except TypeError:
+            return ()
+
     @overload
     def first_link(self, key: MetaKey, default: None=None) -> Optional[str]: ...
 

conservancy_beancount/reports/core.py

@@ -335,15 +335,10 @@ class RelatedPostings(Sequence[data.Posting]):
     def __len__(self) -> int:
         return len(self._postings)
 
-    def _all_meta_links(self, key: MetaKey) -> Iterator[str]:
-        for post in self:
-            try:
-                yield from post.meta.get_links(key)
-            except TypeError:
-                pass
-
     def all_meta_links(self, key: MetaKey) -> Iterator[str]:
-        return filters.iter_unique(self._all_meta_links(key))
+        return filters.iter_unique(
+            link for post in self for link in post.meta.report_links(key)
+        )
 
     @overload
     def first_meta_links(self, key: MetaKey, default: str='') -> Iterator[str]: ...

tests/test_data_metadata.py

@@ -28,6 +28,15 @@ def simple_txn(index=None, key=None):
     ])
 SIMPLE_TXN_METAKEYS = frozenset(['filename', 'lineno', 'note'])
 
+LINK_STRINGS = [
+    '',
+    'link',
+    '  link',
+    'link  ',
+    'link1  link2',
+    ' link1  link2   link3    ',
+]
+
 def test_metadata_transforms_source():
     source = {'1': 'one'}
     meta = data.Metadata(source)
@@ -36,14 +45,7 @@ def test_metadata_transforms_source():
     del meta['1']
     assert set(source) == {'2'}
 
-@pytest.mark.parametrize('value', [
-    '',
-    'link',
-    '  link',
-    'link  ',
-    'link1  link2',
-    ' link1  link2   link3    ',
-])
+@pytest.mark.parametrize('value', LINK_STRINGS)
 def test_get_links(value):
     meta = data.Metadata({'key': value})
     assert list(meta.get_links('key')) == value.split()
@@ -58,6 +60,20 @@ def test_get_links_bad_type(value):
     with pytest.raises(TypeError):
         meta.get_links('key')
 
+@pytest.mark.parametrize('value', LINK_STRINGS)
+def test_report_links(value):
+    meta = data.Metadata({'key': value})
+    assert list(meta.report_links('key')) == value.split()
+
+def test_report_links_missing():
+    meta = data.Metadata({})
+    assert not meta.report_links('key')
+
+@pytest.mark.parametrize('value', testutil.NON_STRING_METADATA_VALUES)
+def test_report_links_bad_type(value):
+    meta = data.Metadata({'key': value})
+    assert not meta.report_links('key')
+
 def test_first_link_from_txn(simple_txn):
     meta = data.PostingMeta(simple_txn, 0)
     assert meta.first_link('note') == 'txn'