fix(parser): support bash-style single-quote splices in values

Author: simoncraf

src/dotenv/parser.py

@@ -23,6 +23,7 @@ def make_regex(string: str, extra_flags: int = 0) -> Pattern[str]:
 _unquoted_key = make_regex(r"([^=\#\s]+)")
 _equal_sign = make_regex(r"(=[^\S\r\n]*)")
 _single_quoted_value = make_regex(r"'((?:\\'|[^'])*)'")
+_single_quote_splice = make_regex('"\'"')
 _double_quoted_value = make_regex(r'"((?:\\"|[^"])*)"')
 _unquoted_value = make_regex(r"([^\r\n]*)")
 _comment = make_regex(r"(?:[^\S\r\n]*#[^\r\n]*)?")
@@ -125,11 +126,23 @@ def parse_unquoted_value(reader: Reader) -> str:
     return re.sub(r"\s+#.*", "", part).rstrip()
 
 
+def parse_single_quoted_value(reader: Reader) -> str:
+    splice_value = '"\'"'
+    value = ""
+    while True:
+        (part,) = reader.read_regex(_single_quoted_value)
+        value += decode_escapes(_single_quote_escapes, part)
+        if reader.peek(len(splice_value)) != splice_value:
+            break
+        reader.read_regex(_single_quote_splice)
+        value += "'"
+    return value
+
+
 def parse_value(reader: Reader) -> str:
     char = reader.peek(1)
     if char == "'":
-        (value,) = reader.read_regex(_single_quoted_value)
-        return decode_escapes(_single_quote_escapes, value)
+        return parse_single_quoted_value(reader)
     elif char == '"':
         (value,) = reader.read_regex(_double_quoted_value)
         return decode_escapes(_double_quote_escapes, value)

tests/test_main.py

@@ -663,6 +663,7 @@ def test_dotenv_values_file(dotenv_path):
         # With quotes
         ({"b": "c"}, 'a="${b}"', True, {"a": "c"}),
         ({"b": "c"}, "a='${b}'", True, {"a": "c"}),
+        ({}, "a='b'\"'\"'c'", True, {"a": "b'c"}),
         # With surrounding text
         ({"b": "c"}, "a=x${b}y", True, {"a": "xcy"}),
         # Self-referential

tests/test_parser.py

@@ -295,6 +295,17 @@
                 )
             ],
         ),
+        (
+            "a='b'\"'\"'c'",
+            [
+                Binding(
+                    key="a",
+                    value="b'c",
+                    original=Original(string="a='b'\"'\"'c'", line=1),
+                    error=False,
+                )
+            ],
+        ),
         (
             "a=à",
             [