Don't encode verbatim fields (eg url) (#415)

CHANGELOG.md

@@ -182,4 +182,5 @@ Providing multiple input files will only work in `--modify`/`-m` mode.
 
 - Support filenames with spaces (#416, #428)
 - Do not flatten braces which contain commands (#407, #423)
-- Upgrade dependencies
+- Do not encode special characters in verbatim fields like url (#415)
+- Upgrade dependencies

src/format.ts

@@ -21,6 +21,21 @@ import {
 	wrapText,
 } from "./utils";
 
+/**
+ * The following fields are listed in the BibLaTeX documentation as verbatim (may contain
+ * special characters). Source: Kime et al (2024) The biblatex Package (v3.20).
+ */
+const VERBATIM_FIELDS = [
+	"url",
+	"doi",
+	"eprint",
+	"file",
+	"verba",
+	"verbb",
+	"verbc",
+	"pdf",
+];
+
 export function formatBibtex(
 	ast: RootNode,
 	options: OptionsNormalized,
@@ -207,8 +222,9 @@ export function formatValue(
 			if (nameLowerCase === "url" && encodeUrls) {
 				value = escapeURL(value);
 			}
-			// escape special characters like %
-			if (enableEscape) {
+			// escape special characters like %. Do not do this on the url field, which is a
+			// special bibtex field where special characters are output verbatim.
+			if (!VERBATIM_FIELDS.includes(nameLowerCase) && enableEscape) {
 				value = escapeSpecialCharacters(value);
 			}
 			if (nameLowerCase === "pages") {

test/encode-urls.spec.ts

@@ -2,29 +2,26 @@ import { strictEqual } from "node:assert";
 import { bibtex, bibtexTidy, test } from "./utils";
 
 const input = bibtex`
-
 @inproceedings{Smith2009,
-    author="Caroline JA Smith",
-    year=2009,
-    month=dec,
-    title={{Quantum somethings}},journal={Journal of {B}lah},
-    booktitle={JOURNAL OF SOMETHINGS},
   url={http://example.com/something_with/unusual?characters=faoo#bar}
   }`;
 
-const output = bibtex`
+const expectedUnencoded = bibtex`
+@inproceedings{Smith2009,
+  url           = {http://example.com/something_with/unusual?characters=faoo#bar}
+}
+`;
+
+const expectedEncoded = bibtex`
 @inproceedings{Smith2009,
-  author        = "Caroline JA Smith",
-  year          = 2009,
-  month         = dec,
-  title         = {{Quantum somethings}},
-  journal       = {Journal of {B}lah},
-  booktitle     = {JOURNAL OF SOMETHINGS},
-  url           = {http://example.com/something\%5Fwith/unusual?characters=faoo\#bar}
+  url           = {http://example.com/something\%5Fwith/unusual?characters=faoo#bar}
 }
 `;
 
 test("encode urls", async () => {
-	const tidied = await bibtexTidy(input, { encodeUrls: true });
-	strictEqual(tidied.bibtex, output);
+	const output1 = await bibtexTidy(input, { encodeUrls: false });
+	strictEqual(output1.bibtex, expectedUnencoded);
+
+	const output2 = await bibtexTidy(input, { encodeUrls: true });
+	strictEqual(output2.bibtex, expectedEncoded);
 });