Allow escaped characters in IEEEtran DOI note

bibtex_linter/ieeetran_rules.py

@@ -11,6 +11,30 @@
 )
 
 
+# LaTeX escapes of special characters that can appear in a DOI, mapped to the character they represent
+_LATEX_ESCAPES = {
+    r"\textasciitilde{}": "~",
+    r"\textasciitilde": "~",
+    r"\~{}": "~",
+    r"\_": "_",
+    r"\#": "#",
+    r"\%": "%",
+    r"\&": "&",
+    r"\$": "$",
+}
+_LATEX_ESCAPE_PATTERN = re.compile("|".join(re.escape(escape) for escape in _LATEX_ESCAPES))
+
+
+def _unescape_latex(text: str) -> str:
+    """
+    Replace the LaTeX escapes of special characters (e.g. `\\_`) in the given text with the characters themselves.
+
+    :param text: The text to unescape
+    :return: The text with all escaped special characters unescaped
+    """
+    return _LATEX_ESCAPE_PATTERN.sub(lambda match: _LATEX_ESCAPES[match.group(0)], text)
+
+
 @linter_rule(entry_type=None)
 def check_url_field(entry: BibTeXEntry) -> List[str]:
     """
@@ -22,8 +46,9 @@ def check_url_field(entry: BibTeXEntry) -> List[str]:
     doi: \\href{https://doi.org/10.xxxx/yyy}{10.xxxx/yyy}
     ```
     Note, that the backslash had to be escaped here and is only meant to be a single one.
-    In the DOI form, the shown DOI must be the same as the DOI in the URL. Since a DOI is persistent, it has no
-    access date.
+    In the DOI form, the shown DOI must be the same as the DOI in the URL. Special characters in the shown DOI may be
+    escaped (e.g. `10.1007/11574620\\_45`), since the shown DOI is typeset as normal text. Since a DOI is persistent,
+    it has no access date.
 
     :param entry: The BibTeXEntry
     :return: A list of string descriptions of rule violations for this entry.
@@ -38,8 +63,10 @@ def check_url_field(entry: BibTeXEntry) -> List[str]:
     if "note" in entry.fields.keys():
         note_content: str = entry.fields["note"]
         online_pattern = r"^\[ONLINE\]\. Available: \\url\{(.+?)\}, Accessed: (\d{4}-\d{2}-\d{2})$"
-        doi_pattern = r"^doi: \\href\{https://doi\.org/(10\.\d{4,9}/\S+)\}\{\1\}$"
-        if not (re.match(online_pattern, note_content) or re.match(doi_pattern, note_content)):
+        doi_pattern = r"^doi: \\href\{https://doi\.org/(10\.\d{4,9}/\S+)\}\{(\S+)\}$"
+        doi_match = re.match(doi_pattern, note_content)
+        is_valid_doi = doi_match is not None and doi_match.group(1) == _unescape_latex(doi_match.group(2))
+        if not (re.match(online_pattern, note_content) or is_valid_doi):
             invariant_violations.append(
                 "Contains a malformed field [note]. "
                 "Make sure the [note] field follows one of the following patterns: "

test/test_verification.py

@@ -118,6 +118,38 @@ def test_doi_note_mismatching_doi(self) -> None:
         )
         self.assertEqual([self.MALFORMED_NOTE], check_url_field(entry))
 
+    def test_doi_note_unescaped_underscore(self) -> None:
+        entry = BibTeXEntry(
+            entry_type="incollection",
+            name="doi_underscore",
+            fields={"note": "doi: \\href{https://doi.org/10.1007/11574620_45}{10.1007/11574620_45}"}
+        )
+        self.assertEqual([], check_url_field(entry))
+
+    def test_doi_note_escaped_special_characters(self) -> None:
+        for url_doi, shown_doi in (
+            ("10.1007/11574620_45", "10.1007/11574620\\_45"),
+            ("10.1007/978-3-642-25073-6_18", "10.1007/978-3-642-25073-6\\_18"),
+            ("10.1234/a#b%c&d$e", "10.1234/a\\#b\\%c\\&d\\$e"),
+            ("10.1234/a~b", "10.1234/a\\textasciitilde{}b"),
+            ("10.1234/a~b", "10.1234/a\\~{}b"),
+        ):
+            with self.subTest(shown_doi=shown_doi):
+                entry = BibTeXEntry(
+                    entry_type="incollection",
+                    name="doi_escaped",
+                    fields={"note": f"doi: \\href{{https://doi.org/{url_doi}}}{{{shown_doi}}}"}
+                )
+                self.assertEqual([], check_url_field(entry))
+
+    def test_doi_note_escaped_mismatching_doi(self) -> None:
+        entry = BibTeXEntry(
+            entry_type="incollection",
+            name="doi_escaped_mismatch",
+            fields={"note": "doi: \\href{https://doi.org/10.1007/11574620_45}{10.1007/11574620\\_46}"}
+        )
+        self.assertEqual([self.MALFORMED_NOTE], check_url_field(entry))
+
     def test_doi_note_with_access_date(self) -> None:
         entry = BibTeXEntry(
             entry_type="article",