Preserve literal inline comment markers in parsed values

CHANGELOG

@@ -1,3 +1,9 @@
+Unreleased
+==========
+
+* preserve inline ``#`` and ``;`` in values unless preceded by whitespace when
+  using ``IniConfig.parse()``, including continuation lines (regarding #83)
+
 2.3.1
 =====
 

README.rst

@@ -32,7 +32,9 @@ If you have an ini file like this:
         line1
         line2
 
-use ``IniConfig.parse()`` to strip inline comments from values:
+use ``IniConfig.parse()`` to strip inline comments from values. Inline ``#`` and
+``;`` start comments only when preceded by whitespace, so values such as URL
+fragments and semicolon-separated text remain intact:
 
 .. code-block:: pycon
 

src/iniconfig/__init__.py

@@ -139,8 +139,8 @@ def parse(
             data: Optional INI content as string. If None, reads from path.
             encoding: Encoding to use when reading the file (default: utf-8)
             strip_inline_comments: Whether to strip inline comments from values
-                (default: True). When True, comments starting with # or ; are
-                removed from values, matching the behavior for section comments.
+                (default: True). When True, # or ; preceded by whitespace starts
+                a comment. Other occurrences remain part of the value.
             strip_section_whitespace: Whether to strip whitespace from section and key names
                 (default: False). When True, strips Unicode whitespace from section and key names,
                 addressing issue #4. When False, preserves existing behavior for backward compatibility.

src/iniconfig/_parse.py

@@ -138,21 +138,24 @@ def _parseline(
         key_name = name.strip()
 
         # Strip value
-        value = value.strip()
         # Strip inline comments from values if requested (issue #55)
         if strip_inline_comments:
-            for c in COMMENTCHARS:
-                value = value.split(c)[0].rstrip()
+            value = _strip_inline_comment(value)
 
-        return key_name, value
+        return key_name, value.strip()
     # continuation
     else:
-        line = line.strip()
         # Strip inline comments from continuations if requested (issue #55)
         if strip_inline_comments:
-            for c in COMMENTCHARS:
-                line = line.split(c)[0].rstrip()
-        return None, line
+            line = _strip_inline_comment(line)
+        return None, line.strip()
+
+
+def _strip_inline_comment(value: str) -> str:
+    for index, char in enumerate(value):
+        if index and char in COMMENTCHARS and value[index - 1].isspace():
+            return value[:index]
+    return value
 
 
 def iscommentline(line: str) -> bool:

testing/test_iniconfig.py

@@ -316,6 +316,35 @@ def test_iscommentline_true(line: str) -> None:
     assert iscommentline(line)
 
 
+@pytest.mark.parametrize("continuation", [False, True])
+@pytest.mark.parametrize(
+    ("value", "expected"),
+    [
+        ("http://example.org/#fragment", "http://example.org/#fragment"),
+        ("a;b", "a;b"),
+        ("a#b;c", "a#b;c"),
+        ("a#b ; comment", "a#b"),
+        ("a;b # comment", "a;b"),
+        ("a#b;still-value ; comment # later", "a#b;still-value"),
+        ("value\t# comment", "value"),
+        ("value\u00a0; comment", "value"),
+        ("value # comment; later", "value"),
+    ],
+)
+def test_parse_inline_comment_requires_whitespace(
+    value: str, expected: str, continuation: bool
+) -> None:
+    assignment = f"key =\n    {value}" if continuation else f"key = {value}"
+    config = IniConfig.parse("test.ini", data=f"[section]\n{assignment}")
+    assert config["section"]["key"] == expected
+
+
+@pytest.mark.parametrize("value", ["#literal", ";literal"])
+def test_parse_comment_marker_immediately_after_separator(value: str) -> None:
+    config = IniConfig.parse("test.ini", data=f"[section]\nkey={value}")
+    assert config["section"]["key"] == value
+
+
 def test_parse_strips_inline_comments() -> None:
     """Test that IniConfig.parse() strips inline comments from values by default."""
     config = IniConfig.parse(
@@ -332,7 +361,7 @@ def test_parse_strips_inline_comments() -> None:
     )
     assert config["section1"]["name1"] == "value1"
     assert config["section1"]["name2"] == "value2"
-    assert config["section1"]["name3"] == "value3"
+    assert config["section1"]["name3"] == "value3# no space before comment"
     assert config["section1"]["list"] == "a, b, c"