Fixes #409: IndexError on empty strong mark on version. (#410)

ChangeLog.rst

@@ -1,3 +1,10 @@
+Unreleased
+==========
+----
+
+* Fixes #409: IndexError on empty strong mark.
+
+
 2024.2.25
 =========
 ----

html2text/__init__.py

@@ -438,6 +438,10 @@ def handle_tag(
             if (
                 start
                 and self.preceding_data
+                # When `self.strong_mark` is set to empty, the next condition
+                # will cause IndexError since it's trying to match the data
+                # with the first character of the `self.strong_mark`.
+                and len(self.strong_mark) > 0
                 and self.preceding_data[-1] == self.strong_mark[0]
             ):
                 strong = " " + self.strong_mark

setup.cfg

@@ -42,10 +42,12 @@ html2text = py.typed
 [flake8]
 max_line_length = 88
 extend-ignore = E203
+extend-exclude = env/
 
 [isort]
 combine_as_imports = True
 profile = black
+extend_skip = env/
 
 [mypy]
 python_version = 3.8

test/test_html2text.py

@@ -240,3 +240,12 @@ def _skip_certain_tags(h2t, tag, attrs, start):
         "some <i>italics</i> too."
     )
     assert ret == "this is a txt and this is a with text and some _italics_ too.\n\n"
+
+
+def test_strong_emptied() -> None:
+    """When strong is being set to empty, it should not mark it."""
+    h = html2text.HTML2Text()
+    h.emphasis_mark = "_"
+    h.strong_mark = ""
+    string = "A <b>B</b> <i>C</i>."
+    assert h.handle(string) == "A B _C_.\n\n"