Preserve embedded comment characters in parsed INI values

README.rst

@@ -56,3 +56,8 @@ use ``IniConfig.parse()`` to strip inline comments from values:
 The ``IniConfig()`` constructor preserves inline comments in values for backward
 compatibility. Use ``IniConfig.parse(..., strip_inline_comments=False)`` to
 preserve them when using the parsing method.
+
+When inline comment stripping is enabled, ``#`` and ``;`` start a comment only
+at the beginning of a value or after whitespace. Characters within a value,
+such as the ``#`` in ``https://example.com/#fragment`` or the ``;`` in ``a;b``,
+are preserved. The same rule applies to continuation lines.

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 ; at the beginning of a value
+                or after whitespace starts a comment, including on continuation lines.
             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

@@ -141,20 +141,25 @@ def _parseline(
         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_comments(value)
 
         return key_name, value
     # 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()
+            line = _strip_inline_comments(line)
         return None, line
 
 
+def _strip_inline_comments(value: str) -> str:
+    for index, char in enumerate(value):
+        if char in COMMENTCHARS and (index == 0 or value[index - 1].isspace()):
+            return value[:index].rstrip()
+    return value
+
+
 def iscommentline(line: str) -> bool:
     c = line.lstrip()[:1]
     return c in COMMENTCHARS

testing/test_iniconfig.py

@@ -332,7 +332,7 @@ 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"
 
 
@@ -353,6 +353,40 @@ def test_parse_strips_inline_comments_from_continuations() -> None:
     assert config["section"]["names"] == "Alice\nBob\nCharlie"
 
 
+@pytest.mark.parametrize("continuation", [False, True])
+@pytest.mark.parametrize(
+    ("value", "expected"),
+    [
+        ("http://example.com/#fragment", "http://example.com/#fragment"),
+        ("a#b", "a#b"),
+        ("d;e", "d;e"),
+        ("a#b ; comment", "a#b"),
+        ("d;e # comment", "d;e"),
+        ("value # comment;more", "value"),
+        ("value ; comment#more", "value"),
+        ("value\t# comment", "value"),
+        ("value\u00a0; comment", "value"),
+        ("value#", "value#"),
+        ("value;", "value;"),
+    ],
+)
+def test_parse_inline_comment_boundaries(
+    value: str, expected: str, continuation: bool
+) -> None:
+    if continuation:
+        data = f"[section]\nkey =\n    {value}\n"
+    else:
+        data = f"[section]\nkey = {value}\n"
+    config = IniConfig.parse("test.ini", data=data)
+    assert config["section"]["key"] == expected
+
+
+@pytest.mark.parametrize("value", ["# comment", "; comment"])
+def test_parse_comment_only_value(value: str) -> None:
+    config = IniConfig.parse("test.ini", data=f"[section]\nkey = {value}\n")
+    assert config["section"]["key"] == ""
+
+
 def test_parse_preserves_inline_comments_when_disabled() -> None:
     """Test that IniConfig.parse(strip_inline_comments=False) preserves comments."""
     config = IniConfig.parse(