DXF: read every ENTITIES section, not only the last (fixes #865) (#869)

crates/io/src/dxf_read.rs

@@ -1603,7 +1603,8 @@ pub fn read(bytes: &[u8]) -> Result<Drawing> {
                     }
                 }
             }
-            "ENTITIES" => entities = parse_entities(&records(&s.tags), &mut d, &mut rx),
+            // A damaged file may split its entities over several ENTITIES sections (#865).
+            "ENTITIES" => entities.extend(parse_entities(&records(&s.tags), &mut d, &mut rx)),
             "OBJECTS" => {
                 for (k, tg) in records(&s.tags) {
                     objs.add(&k, &tg);

crates/io/tests/split_entities_section.rs

@@ -0,0 +1,19 @@
+//! A damaged DXF can split its entities over several ENTITIES sections (with stray header
+//! variables and ENDSECs between them, and no EOF). Every section is read, not just the last
+//! one (#865).
+
+use cadcraft_doc::EntityKind;
+
+#[test]
+fn entities_of_every_entities_section_are_read() {
+    let text = "0\nSECTION\n2\nENTITIES\n\
+                0\nTEXT\n8\n0\n10\n0\n20\n0\n40\n1\n1\nA\n\
+                0\nLINE\n8\n0\n10\n0\n20\n0\n11\n1\n21\n0\n\
+                0\nENDSEC\n9\n$EXTMIN\n10\n0\n20\n0\n0\nENDSEC\n\
+                0\nSECTION\n2\nENTITIES\n0\nLINE\n8\n0\n10\n0\n20\n1\n11\n1\n21\n1\n0\nENDSEC\n\
+                0\nSECTION\n2\nENTITIES\n0\nENDSEC\n";
+    let d = cadcraft_io::read(text.as_bytes(), "t.dxf").unwrap();
+    let lines = d.model.iter().filter(|e| matches!(e.kind, EntityKind::Line(_))).count();
+    let texts = d.model.iter().filter(|e| matches!(e.kind, EntityKind::Text(_))).count();
+    assert_eq!((lines, texts, d.model.len()), (2, 1, 3));
+}