fix: fix a bug in EOL handling

A non-NL character acting as EOL and seen by captureTo would cause a crash in
some cases.

lib/saxes.js

@@ -803,7 +803,7 @@ class SaxesParser {
    * @private
    *
    * @param {number[]} chars An array of codepoints. Encountering a character in
-   * the array ends the capture.
+   * the array ends the capture. (``chars`` may safely contain ``NL``.)
    *
    * @return {number} The character code that made the capture end, or ``EOC``
    * if we hit the end of the chunk. The return value cannot be NL_LIKE: NL is
@@ -813,22 +813,17 @@ class SaxesParser {
     let { i: start } = this;
     const { chunk } = this;
     while (true) {
-      let c = this.getCode();
-      switch (c) {
-      case NL_LIKE:
-        this.text += `${chunk.slice(start, this.prevI)}\n`;
-        start = this.i;
-        c = NL;
-        break;
-      case EOC:
-        this.text += chunk.slice(start);
-        return EOC;
-      default:
+      const c = this.getCode();
+      const isNLLike = c === NL_LIKE;
+      const final = isNLLike ? NL : c;
+      if (final === EOC || chars.includes(final)) {
+        this.text += chunk.slice(start, this.prevI);
+        return final;
       }
 
-      if (chars.includes(c)) {
-        this.text += chunk.slice(start, this.prevI);
-        return c;
+      if (isNLLike) {
+        this.text += `${chunk.slice(start, this.prevI)}\n`;
+        start = this.i;
       }
     }
   }
@@ -838,7 +833,8 @@ class SaxesParser {
    *
    * @private
    *
-   * @param {number} char The codepoint that ends the capture.
+   * @param {number} char The codepoint that ends the capture. **NOTE ``char``
+   * MAY NOT CONTAIN ``NL``.** Passing ``NL`` will result in buggy behavior.
    *
    * @return {boolean} ``true`` if we ran into the character. Otherwise, we ran
    * into the end of the current chunk.
@@ -1486,7 +1482,7 @@ class SaxesParser {
   /** @private */
   sPIRest() {
     const c = this.captureWhileNameCheck("piTarget");
-    if ((c === QUESTION || isS(c))) {
+    if (c === QUESTION || isS(c)) {
       this.piIsXMLDecl = this.piTarget === "xml";
       if (this.piIsXMLDecl && !this.xmlDeclPossible) {
         this.fail("an XML declaration must be at the start of the document.");

test/eol-handling.js

@@ -58,6 +58,242 @@ describe("eol handling", () => {
     });
   });
 
+  // The comprehensive test is meant to have EOL in all possible contexts.
+  describe("comprehensive", () => {
+    const nl = `\
+<?xml
+version
+=
+"1.0"
+encoding
+=
+"utf-8"
+standalone
+=
+"no"
+?>
+<!DOCTYPE
+root
+[
+<!--
+I'm a test.
+-->
+<?
+I'm a test.
+?>
+<!NOTATION
+not1
+SYSTEM
+"]>"
+>
+]>
+<!--
+-->
+<?fnord
+?>
+<moo
+a
+=
+"12
+        3"
+b
+=
+"
+z
+"
+>
+abc
+&#xD;
+
+<!--
+-->
+<?fnord
+?>
+<abc
+a
+=
+"bc"
+/>
+</moo
+>
+`;
+    const xmlDeclEnd = nl.indexOf("?>");
+
+    const expect = [
+      ["text", "\n"],
+      ["doctype", `
+root
+[
+<!--
+I'm a test.
+-->
+<?
+I'm a test.
+?>
+<!NOTATION
+not1
+SYSTEM
+"]>"
+>
+]`],
+      ["text", "\n"],
+      ["comment", "\n"],
+      ["text", "\n"],
+      ["processinginstruction", { target: "fnord", body: "" }],
+      ["text", "\n"],
+      ["opentagstart", { name: "moo", attributes: {} }],
+      ["opentag", {
+        name: "moo",
+        attributes: {
+          a: "12\n        3",
+          b: "\nz\n",
+        },
+        isSelfClosing: false,
+      }],
+      ["text", `
+abc
+\r
+
+`],
+      ["comment", "\n"],
+      ["text", "\n"],
+      ["processinginstruction", { target: "fnord", body: "" }],
+      ["text", "\n"],
+      ["opentagstart", { name: "abc", attributes: {} }],
+      ["opentag", {
+        name: "abc",
+        attributes: {
+          a: "bc",
+        },
+        isSelfClosing: true,
+      }],
+      ["closetag", {
+        name: "abc",
+        attributes: {
+          a: "bc",
+        },
+        isSelfClosing: true,
+      }],
+      ["text", "\n"],
+      ["closetag", {
+        name: "moo",
+        attributes: {
+          a: "12\n        3",
+          b: "\nz\n",
+        },
+        isSelfClosing: false,
+      }],
+      ["text", "\n"],
+    ];
+
+    describe("nl", () => {
+      test({
+        name: "one chunk",
+        xml: nl,
+        expect,
+      });
+
+      test({
+        name: "char-by-char",
+        expect,
+        fn(parser) {
+          for (const x of nl) {
+            parser.write(x);
+          }
+          parser.close();
+        },
+      });
+    });
+
+    describe("cr", () => {
+      const cr = nl.replace(/\n/g, "\r");
+
+      test({
+        name: "one chunk",
+        xml: cr,
+        expect,
+      });
+
+      test({
+        name: "char-by-char",
+        expect,
+        fn(parser) {
+          for (const x of cr) {
+            parser.write(x);
+          }
+          parser.close();
+        },
+      });
+    });
+
+    describe("crnl", () => {
+      const crnl = nl.replace(/\n/g, "\r\n");
+
+      test({
+        name: "one chunk",
+        xml: crnl,
+        expect,
+      });
+
+      test({
+        name: "char-by-char",
+        expect,
+        fn(parser) {
+          for (const x of crnl) {
+            parser.write(x);
+          }
+          parser.close();
+        },
+      });
+    });
+
+    describe("nel", () => {
+      // We have to switch the EOL characters after the XML declaration.
+      const nel = nl.slice(0, xmlDeclEnd).replace("1.0", "1.1") +
+            nl.slice(xmlDeclEnd).replace(/\n/g, "\u0085");
+
+      test({
+        name: "one chunk",
+        xml: nel,
+        expect,
+      });
+
+      test({
+        name: "char-by-char",
+        expect,
+        fn(parser) {
+          for (const x of nel) {
+            parser.write(x);
+          }
+          parser.close();
+        },
+      });
+    });
+
+    describe("ls", () => {
+      // We have to switch the EOL characters after the XML declaration.
+      const ls = nl.slice(0, xmlDeclEnd).replace("1.0", "1.1") +
+            nl.slice(xmlDeclEnd).replace(/\n/g, "\u2028");
+
+      test({
+        name: "one chunk",
+        xml: ls,
+        expect,
+      });
+
+      test({
+        name: "char-by-char",
+        expect,
+        fn(parser) {
+          for (const x of ls) {
+            parser.write(x);
+          }
+          parser.close();
+        },
+      });
+    });
+  });
+
   describe("bad start", () => {
     const xml = `
 <?xml version="1.0" encoding="utf-8"?><doc/>`;