fix potential errors in _to_bib_item when parsing the url field

bib_lookup/bib_lookup.py

@@ -788,7 +788,7 @@ def _to_bib_item(
             field_dict = OrderedDict()
             for line in lines[1:-1]:
                 key, *val = line.strip().split("=")  # urls might contain "="
-                val = "".join(val)
+                val = "=".join(val)
                 if key.strip().lower() in BIB_FIELDS:
                     # field_dict[key.strip()] = val.strip(", ")
                     field_dict[key.strip()] = val

sample-files/large_database.bib

@@ -5900,3 +5900,11 @@ @inproceedings{kiyasseh2021clocs
           year = {2021},
   organization = {{PMLR}}
 }
+
+@inproceedings{dosovitskiy2021_vit,
+      title = {{An Image is Worth 16x16 Words: Transformers for Image Recognition at Scale}},
+     author = {Alexey Dosovitskiy and Lucas Beyer and Alexander Kolesnikov and Dirk Weissenborn and Xiaohua Zhai and Thomas Unterthiner and Mostafa Dehghani and Matthias Minderer and Georg Heigold and Sylvain Gelly and Jakob Uszkoreit and Neil Houlsby},
+  booktitle = {International Conference on Learning Representations},
+       year = {2021},
+        url = {https://openreview.net/forum?id=YicbFdNTTy}
+}

test/test_io.py

@@ -50,7 +50,12 @@ def test_io_from_file():
     _OUTPUT_FILE_1.unlink()
 
     bib_items = bl.read_bib_file(_LARGE_DATABASE_FILE, cache=True)
-    assert len(bib_items) == len(bl) == 608
+    assert len(bib_items) == len(bl) == 609
+    special_item = [
+        item for item in bib_items if item.identifier == "dosovitskiy2021_vit"
+    ][0]
+    # make sure that "=" is not escaped in the url field after reading from file
+    assert special_item.url == "https://openreview.net/forum?id=YicbFdNTTy"
     bl.clear_cache()
     assert len(bl) == 0