Better error messages in SVG backend for Keywords metadata

oscargus · oscargus · commit 0b0f279cbae7 · 2022-06-15T10:55:56.000+02:00
diff --git a/lib/matplotlib/backends/backend_svg.py b/lib/matplotlib/backends/backend_svg.py
@@ -376,14 +376,14 @@ def _write_metadata(self, metadata):
                     elif isinstance(d, (datetime.datetime, datetime.date)):
                         dates.append(d.isoformat())
                     else:
-                        raise ValueError(
+                        raise TypeError(
                             'Invalid type for Date metadata. '
                             'Expected iterable of str, date, or datetime, '
                             'not {!r}.'.format(type(d)))
             else:
-                raise ValueError('Invalid type for Date metadata. '
-                                 'Expected str, date, datetime, or iterable '
-                                 'of the same, not {!r}.'.format(type(date)))
+                raise TypeError('Invalid type for Date metadata. '
+                                'Expected str, date, datetime, or iterable '
+                                'of the same, not {!r}.'.format(type(date)))
             metadata['Date'] = '/'.join(dates)
         elif 'Date' not in metadata:
             # Do not add `Date` if the user explicitly set `Date` to `None`
@@ -444,14 +444,23 @@ def ensure_metadata(mid):
         if keywords is not None:
             if isinstance(keywords, str):
                 keywords = [keywords]
-
-            mid = ensure_metadata(mid)
-            writer.start('dc:subject')
-            writer.start('rdf:Bag')
-            for keyword in keywords:
-                writer.element('rdf:li', text=keyword)
-            writer.end('rdf:Bag')
-            writer.end('dc:subject')
+            if np.iterable(keywords):
+                mid = ensure_metadata(mid)
+                writer.start('dc:subject')
+                writer.start('rdf:Bag')
+                for keyword in keywords:
+                    if isinstance(keyword, str):
+                        writer.element('rdf:li', text=keyword)
+                    else:
+                        raise TypeError('Invalid type for Keywords metadata. '
+                                        'Expected iterable of str'
+                                        ', not {!r}.'.format(type(keyword)))
+                writer.end('rdf:Bag')
+                writer.end('dc:subject')
+            else:
+                raise TypeError('Invalid type for Keywords metadata. '
+                                'Expected str or iterable '
+                                'of str, not {!r}.'.format(type(keywords)))
 
         if mid is not None:
             writer.close(mid)
diff --git a/lib/matplotlib/tests/test_backend_svg.py b/lib/matplotlib/tests/test_backend_svg.py
@@ -469,3 +469,29 @@ def test_svg_metadata():
     values = [node.text for node in
               rdf.findall(f'./{CCNS}Work/{DCNS}subject/{RDFNS}Bag/{RDFNS}li')]
     assert values == metadata['Keywords']
+
+
+@pytest.mark.parametrize('metadata,error,message', [
+    ({'Date': 1}, TypeError, "Invalid type for Date metadata. Expected str"),
+    ({'Date': [1]}, TypeError,
+     "Invalid type for Date metadata. Expected iterable"),
+    ({'Keywords': 1}, TypeError,
+     "Invalid type for Keywords metadata. Expected str"),
+    ({'Keywords': [1]}, TypeError,
+     "Invalid type for Keywords metadata. Expected iterable"),
+    ({'Foo': 'Bar'}, ValueError, "Unknown metadata key"),
+    ])
+def test_svg_incorrect_metadata(metadata, error, message):
+    with pytest.raises(error, match=message), BytesIO() as fd:
+        fig, ax = plt.subplots()
+        fig.savefig(fd, format='svg', metadata=metadata)
+
+
+def test_svg_escape():
+    fig, ax = plt.subplots()
+    fig.text(0.5, 0.5, "<\'\"&>", gid="<\'\"&>")
+    ax.set_axis_off()
+    with BytesIO() as fd:
+        fig.savefig(fd, format='svg')
+        buf = fd.getvalue().decode()
+        assert '&lt;&apos;&quot;&amp;&gt;"' in buf
