We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
"\n" isn't mangled appropriately
    => (mangle "\n")
    'hyx_XUnX'
    => (unmangle (mangle "\n"))
    Traceback (most recent call last):
    …
    ValueError: invalid literal for int() with base 16: 'n'


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `hy/lex/__init__.py`
Content:
```
1 # Copyright 2018 the authors.
2 # This file is part of Hy, which is free software licensed under the Expat
3 # license. See the LICENSE.
4 
5 from __future__ import unicode_literals
6 
7 import re
8 import sys
9 import unicodedata
10 
11 from hy._compat import str_type, isidentifier, UCS4
12 from hy.lex.exceptions import PrematureEndOfInput, LexException  # NOQA
13 from hy.models import HyExpression, HySymbol
14 
15 try:
16     from io import StringIO
17 except ImportError:
18     from StringIO import StringIO
19 
20 
21 def hy_parse(source):
22     """Parse a Hy source string.
23 
24     Parameters
25     ----------
26     source: string
27         Source code to parse.
28 
29     Returns
30     -------
31     out : instance of `types.CodeType`
32     """
33     source = re.sub(r'\A#!.*', '', source)
34     return HyExpression([HySymbol("do")] + tokenize(source + "\n"))
35 
36 
37 def tokenize(buf):
38     """
39     Tokenize a Lisp file or string buffer into internal Hy objects.
40     """
41     from hy.lex.lexer import lexer
42     from hy.lex.parser import parser
43     from rply.errors import LexingError
44     try:
45         return parser.parse(lexer.lex(buf))
46     except LexingError as e:
47         pos = e.getsourcepos()
48         raise LexException("Could not identify the next token.",
49                            pos.lineno, pos.colno, buf)
50     except LexException as e:
51         if e.source is None:
52             e.source = buf
53         raise
54 
55 
56 mangle_delim = 'X'
57 
58 
59 def mangle(s):
60     """Stringify the argument and convert it to a valid Python identifier
61     according to Hy's mangling rules."""
62     def unicode_char_to_hex(uchr):
63         # Covert a unicode char to hex string, without prefix
64         return uchr.encode('unicode-escape').decode('utf-8').lstrip('\\U').lstrip('\\u').lstrip('0')
65 
66     assert s
67 
68     s = str_type(s)
69     s = s.replace("-", "_")
70     s2 = s.lstrip('_')
71     leading_underscores = '_' * (len(s) - len(s2))
72     s = s2
73 
74     if s.endswith("?"):
75         s = 'is_' + s[:-1]
76     if not isidentifier(leading_underscores + s):
77         # Replace illegal characters with their Unicode character
78         # names, or hexadecimal if they don't have one.
79         s = 'hyx_' + ''.join(
80             c
81                if c != mangle_delim and isidentifier('S' + c)
82                  # We prepend the "S" because some characters aren't
83                  # allowed at the start of an identifier.
84                else '{0}{1}{0}'.format(mangle_delim,
85                    unicodedata.name(c, '').lower().replace('-', 'H').replace(' ', '_')
86                    or 'U{}'.format(unicode_char_to_hex(c)))
87             for c in unicode_to_ucs4iter(s))
88 
89     s = leading_underscores + s
90     assert isidentifier(s)
91     return s
92 
93 
94 def unmangle(s):
95     """Stringify the argument and try to convert it to a pretty unmangled
96     form. This may not round-trip, because different Hy symbol names can
97     mangle to the same Python identifier."""
98 
99     s = str_type(s)
100 
101     s2 = s.lstrip('_')
102     leading_underscores = len(s) - len(s2)
103     s = s2
104 
105     if s.startswith('hyx_'):
106         s = re.sub('{0}(U)?([_a-z0-9H]+?){0}'.format(mangle_delim),
107             lambda mo:
108                chr(int(mo.group(2), base=16))
109                if mo.group(1)
110                else unicodedata.lookup(
111                    mo.group(2).replace('_', ' ').replace('H', '-').upper()),
112             s[len('hyx_'):])
113     if s.startswith('is_'):
114         s = s[len("is_"):] + "?"
115     s = s.replace('_', '-')
116 
117     return '-' * leading_underscores + s
118 
119 
120 def unicode_to_ucs4iter(ustr):
121     # Covert a unicode string to an iterable object,
122     # elements in the object are single USC-4 unicode characters
123     if UCS4:
124         return ustr
125     ucs4_list = list(ustr)
126     for i, u in enumerate(ucs4_list):
127         if 0xD7FF < ord(u) < 0xDC00:
128             ucs4_list[i] += ucs4_list[i + 1]
129             del ucs4_list[i + 1]
130     return ucs4_list
131 
132 
133 def read(from_file=sys.stdin, eof=""):
134     """Read from input and returns a tokenized string.
135 
136     Can take a given input buffer to read from, and a single byte as EOF
137     (defaults to an empty string).
138     """
139     buff = ""
140     while True:
141         inn = str(from_file.readline())
142         if inn == eof:
143             raise EOFError("Reached end of file")
144         buff += inn
145         try:
146             parsed = next(iter(tokenize(buff)), None)
147         except (PrematureEndOfInput, IndexError):
148             pass
149         else:
150             break
151     return parsed
152 
153 
154 def read_str(input):
155     return read(StringIO(str_type(input)))
156
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/hy/lex/__init__.py b/hy/lex/__init__.py
--- a/hy/lex/__init__.py
+++ b/hy/lex/__init__.py
@@ -61,7 +61,10 @@
     according to Hy's mangling rules."""
     def unicode_char_to_hex(uchr):
         # Covert a unicode char to hex string, without prefix
-        return uchr.encode('unicode-escape').decode('utf-8').lstrip('\\U').lstrip('\\u').lstrip('0')
+        if len(uchr) == 1 and ord(uchr) < 128:
+            return format(ord(uchr), 'x')
+        return (uchr.encode('unicode-escape').decode('utf-8')
+            .lstrip('\\U').lstrip('\\u').lstrip('\\x').lstrip('0'))
 
     assert s

{"golden_diff": "diff --git a/hy/lex/__init__.py b/hy/lex/__init__.py\n--- a/hy/lex/__init__.py\n+++ b/hy/lex/__init__.py\n@@ -61,7 +61,10 @@\n     according to Hy's mangling rules.\"\"\"\n     def unicode_char_to_hex(uchr):\n         # Covert a unicode char to hex string, without prefix\n-        return uchr.encode('unicode-escape').decode('utf-8').lstrip('\\\\U').lstrip('\\\\u').lstrip('0')\n+        if len(uchr) == 1 and ord(uchr) < 128:\n+            return format(ord(uchr), 'x')\n+        return (uchr.encode('unicode-escape').decode('utf-8')\n+            .lstrip('\\\\U').lstrip('\\\\u').lstrip('\\\\x').lstrip('0'))\n \n     assert s\n", "issue": "\"\\n\" isn't mangled appropriately\n    => (mangle \"\\n\")\r\n    'hyx_XUnX'\r\n    => (unmangle (mangle \"\\n\"))\r\n    Traceback (most recent call last):\r\n    \u2026\r\n    ValueError: invalid literal for int() with base 16: 'n'\r\n\n", "before_files": [{"content": "# Copyright 2018 the authors.\n# This file is part of Hy, which is free software licensed under the Expat\n# license. See the LICENSE.\n\nfrom __future__ import unicode_literals\n\nimport re\nimport sys\nimport unicodedata\n\nfrom hy._compat import str_type, isidentifier, UCS4\nfrom hy.lex.exceptions import PrematureEndOfInput, LexException  # NOQA\nfrom hy.models import HyExpression, HySymbol\n\ntry:\n    from io import StringIO\nexcept ImportError:\n    from StringIO import StringIO\n\n\ndef hy_parse(source):\n    \"\"\"Parse a Hy source string.\n\n    Parameters\n    ----------\n    source: string\n        Source code to parse.\n\n    Returns\n    -------\n    out : instance of `types.CodeType`\n    \"\"\"\n    source = re.sub(r'\\A#!.*', '', source)\n    return HyExpression([HySymbol(\"do\")] + tokenize(source + \"\\n\"))\n\n\ndef tokenize(buf):\n    \"\"\"\n    Tokenize a Lisp file or string buffer into internal Hy objects.\n    \"\"\"\n    from hy.lex.lexer import lexer\n    from hy.lex.parser import parser\n    from rply.errors import LexingError\n    try:\n        return parser.parse(lexer.lex(buf))\n    except LexingError as e:\n        pos = e.getsourcepos()\n        raise LexException(\"Could not identify the next token.\",\n                           pos.lineno, pos.colno, buf)\n    except LexException as e:\n        if e.source is None:\n            e.source = buf\n        raise\n\n\nmangle_delim = 'X'\n\n\ndef mangle(s):\n    \"\"\"Stringify the argument and convert it to a valid Python identifier\n    according to Hy's mangling rules.\"\"\"\n    def unicode_char_to_hex(uchr):\n        # Covert a unicode char to hex string, without prefix\n        return uchr.encode('unicode-escape').decode('utf-8').lstrip('\\\\U').lstrip('\\\\u').lstrip('0')\n\n    assert s\n\n    s = str_type(s)\n    s = s.replace(\"-\", \"_\")\n    s2 = s.lstrip('_')\n    leading_underscores = '_' * (len(s) - len(s2))\n    s = s2\n\n    if s.endswith(\"?\"):\n        s = 'is_' + s[:-1]\n    if not isidentifier(leading_underscores + s):\n        # Replace illegal characters with their Unicode character\n        # names, or hexadecimal if they don't have one.\n        s = 'hyx_' + ''.join(\n            c\n               if c != mangle_delim and isidentifier('S' + c)\n                 # We prepend the \"S\" because some characters aren't\n                 # allowed at the start of an identifier.\n               else '{0}{1}{0}'.format(mangle_delim,\n                   unicodedata.name(c, '').lower().replace('-', 'H').replace(' ', '_')\n                   or 'U{}'.format(unicode_char_to_hex(c)))\n            for c in unicode_to_ucs4iter(s))\n\n    s = leading_underscores + s\n    assert isidentifier(s)\n    return s\n\n\ndef unmangle(s):\n    \"\"\"Stringify the argument and try to convert it to a pretty unmangled\n    form. This may not round-trip, because different Hy symbol names can\n    mangle to the same Python identifier.\"\"\"\n\n    s = str_type(s)\n\n    s2 = s.lstrip('_')\n    leading_underscores = len(s) - len(s2)\n    s = s2\n\n    if s.startswith('hyx_'):\n        s = re.sub('{0}(U)?([_a-z0-9H]+?){0}'.format(mangle_delim),\n            lambda mo:\n               chr(int(mo.group(2), base=16))\n               if mo.group(1)\n               else unicodedata.lookup(\n                   mo.group(2).replace('_', ' ').replace('H', '-').upper()),\n            s[len('hyx_'):])\n    if s.startswith('is_'):\n        s = s[len(\"is_\"):] + \"?\"\n    s = s.replace('_', '-')\n\n    return '-' * leading_underscores + s\n\n\ndef unicode_to_ucs4iter(ustr):\n    # Covert a unicode string to an iterable object,\n    # elements in the object are single USC-4 unicode characters\n    if UCS4:\n        return ustr\n    ucs4_list = list(ustr)\n    for i, u in enumerate(ucs4_list):\n        if 0xD7FF < ord(u) < 0xDC00:\n            ucs4_list[i] += ucs4_list[i + 1]\n            del ucs4_list[i + 1]\n    return ucs4_list\n\n\ndef read(from_file=sys.stdin, eof=\"\"):\n    \"\"\"Read from input and returns a tokenized string.\n\n    Can take a given input buffer to read from, and a single byte as EOF\n    (defaults to an empty string).\n    \"\"\"\n    buff = \"\"\n    while True:\n        inn = str(from_file.readline())\n        if inn == eof:\n            raise EOFError(\"Reached end of file\")\n        buff += inn\n        try:\n            parsed = next(iter(tokenize(buff)), None)\n        except (PrematureEndOfInput, IndexError):\n            pass\n        else:\n            break\n    return parsed\n\n\ndef read_str(input):\n    return read(StringIO(str_type(input)))\n", "path": "hy/lex/__init__.py"}], "after_files": [{"content": "# Copyright 2018 the authors.\n# This file is part of Hy, which is free software licensed under the Expat\n# license. See the LICENSE.\n\nfrom __future__ import unicode_literals\n\nimport re\nimport sys\nimport unicodedata\n\nfrom hy._compat import str_type, isidentifier, UCS4\nfrom hy.lex.exceptions import PrematureEndOfInput, LexException  # NOQA\nfrom hy.models import HyExpression, HySymbol\n\ntry:\n    from io import StringIO\nexcept ImportError:\n    from StringIO import StringIO\n\n\ndef hy_parse(source):\n    \"\"\"Parse a Hy source string.\n\n    Parameters\n    ----------\n    source: string\n        Source code to parse.\n\n    Returns\n    -------\n    out : instance of `types.CodeType`\n    \"\"\"\n    source = re.sub(r'\\A#!.*', '', source)\n    return HyExpression([HySymbol(\"do\")] + tokenize(source + \"\\n\"))\n\n\ndef tokenize(buf):\n    \"\"\"\n    Tokenize a Lisp file or string buffer into internal Hy objects.\n    \"\"\"\n    from hy.lex.lexer import lexer\n    from hy.lex.parser import parser\n    from rply.errors import LexingError\n    try:\n        return parser.parse(lexer.lex(buf))\n    except LexingError as e:\n        pos = e.getsourcepos()\n        raise LexException(\"Could not identify the next token.\",\n                           pos.lineno, pos.colno, buf)\n    except LexException as e:\n        if e.source is None:\n            e.source = buf\n        raise\n\n\nmangle_delim = 'X'\n\n\ndef mangle(s):\n    \"\"\"Stringify the argument and convert it to a valid Python identifier\n    according to Hy's mangling rules.\"\"\"\n    def unicode_char_to_hex(uchr):\n        # Covert a unicode char to hex string, without prefix\n        if len(uchr) == 1 and ord(uchr) < 128:\n            return format(ord(uchr), 'x')\n        return (uchr.encode('unicode-escape').decode('utf-8')\n            .lstrip('\\\\U').lstrip('\\\\u').lstrip('\\\\x').lstrip('0'))\n\n    assert s\n\n    s = str_type(s)\n    s = s.replace(\"-\", \"_\")\n    s2 = s.lstrip('_')\n    leading_underscores = '_' * (len(s) - len(s2))\n    s = s2\n\n    if s.endswith(\"?\"):\n        s = 'is_' + s[:-1]\n    if not isidentifier(leading_underscores + s):\n        # Replace illegal characters with their Unicode character\n        # names, or hexadecimal if they don't have one.\n        s = 'hyx_' + ''.join(\n            c\n               if c != mangle_delim and isidentifier('S' + c)\n                 # We prepend the \"S\" because some characters aren't\n                 # allowed at the start of an identifier.\n               else '{0}{1}{0}'.format(mangle_delim,\n                   unicodedata.name(c, '').lower().replace('-', 'H').replace(' ', '_')\n                   or 'U{}'.format(unicode_char_to_hex(c)))\n            for c in unicode_to_ucs4iter(s))\n\n    s = leading_underscores + s\n    assert isidentifier(s)\n    return s\n\n\ndef unmangle(s):\n    \"\"\"Stringify the argument and try to convert it to a pretty unmangled\n    form. This may not round-trip, because different Hy symbol names can\n    mangle to the same Python identifier.\"\"\"\n\n    s = str_type(s)\n\n    s2 = s.lstrip('_')\n    leading_underscores = len(s) - len(s2)\n    s = s2\n\n    if s.startswith('hyx_'):\n        s = re.sub('{0}(U)?([_a-z0-9H]+?){0}'.format(mangle_delim),\n            lambda mo:\n               chr(int(mo.group(2), base=16))\n               if mo.group(1)\n               else unicodedata.lookup(\n                   mo.group(2).replace('_', ' ').replace('H', '-').upper()),\n            s[len('hyx_'):])\n    if s.startswith('is_'):\n        s = s[len(\"is_\"):] + \"?\"\n    s = s.replace('_', '-')\n\n    return '-' * leading_underscores + s\n\n\ndef unicode_to_ucs4iter(ustr):\n    # Covert a unicode string to an iterable object,\n    # elements in the object are single USC-4 unicode characters\n    if UCS4:\n        return ustr\n    ucs4_list = list(ustr)\n    for i, u in enumerate(ucs4_list):\n        if 0xD7FF < ord(u) < 0xDC00:\n            ucs4_list[i] += ucs4_list[i + 1]\n            del ucs4_list[i + 1]\n    return ucs4_list\n\n\ndef read(from_file=sys.stdin, eof=\"\"):\n    \"\"\"Read from input and returns a tokenized string.\n\n    Can take a given input buffer to read from, and a single byte as EOF\n    (defaults to an empty string).\n    \"\"\"\n    buff = \"\"\n    while True:\n        inn = str(from_file.readline())\n        if inn == eof:\n            raise EOFError(\"Reached end of file\")\n        buff += inn\n        try:\n            parsed = next(iter(tokenize(buff)), None)\n        except (PrematureEndOfInput, IndexError):\n            pass\n        else:\n            break\n    return parsed\n\n\ndef read_str(input):\n    return read(StringIO(str_type(input)))\n", "path": "hy/lex/__init__.py"}]}