wrap() should omit an empty line as output

docs/history.rst

@@ -2,7 +2,8 @@
 History
 =======
 
-0.9.2 *2026-10-02*
+0.9.2 *2026-10-04*
+  * **Bugfix** `wrap()`_ should omit an empty line as output, like `textwrap.wrap()`_ `PR #291`_.
   * **Bugfix** `clip()`_ when using non-default argument, ``tabsize=0``, `PR #288`_.
   * **Bugfix** regional-indicator pairs (flags) when corrected for terminals that show lone regional
     indicators as narrow (xterm, wezterm, VTE, and others) in `wcstwidth()`_ and `width()`_, `PR
@@ -316,6 +317,7 @@ https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c::
 .. _`PR #281`: https://github.com/jquast/wcwidth/pull/281
 .. _`PR #284`: https://github.com/jquast/wcwidth/pull/284
 .. _`PR #288`: https://github.com/jquast/wcwidth/pull/288
+.. _`PR #291`: https://github.com/jquast/wcwidth/pull/291
 .. _`Issue #101`: https://github.com/jquast/wcwidth/issues/101
 .. _`Issue #155`: https://github.com/jquast/wcwidth/issues/155
 .. _`Issue #211`: https://github.com/jquast/wcwidth/issues/211

libwcwidth/src/textwrap.c

@@ -806,6 +806,16 @@ _wrap_chunks(chunklist_t *chunks, const wcwidth_wrap_opts_t *opts, lines_t *line
                     lc.len = rstrip_len(lc.data, lc.len);
                     if (lc.data != NULL)
                         lc.data[lc.len] = '\0';
+                    if (lc.len == 0) {
+                        /*
+                         * The line held only whitespace, which dropping has now emptied.  Skip
+                         * it and leave `first` unchanged so initial_indent still applies to the
+                         * first line with content, as stdlib textwrap and wcwidth.textwrap do.
+                         */
+                        sbuf_free(&lc);
+                        cl_free(&cur);
+                        continue;
+                    }
                 }
                 sbuf_t fl;
                 sbuf_init(&fl);

libwcwidth/tests/test_textwrap.c

@@ -289,6 +289,26 @@ TEST(wrap_max_lines_placeholder)
     free(out);
 }
 
+TEST(wrap_drops_leading_whitespace_only_line)
+{
+    char *out;
+    size_t len;
+    wcwidth_wrap_opts_t o = WCWIDTH_WRAP_OPTS_DEFAULT;
+    const char *exp[] = {"h", "e", "l", "l", "o"};
+    const char *exp_ws[] = {" ", "h", "e", "l", "l", "o"};
+
+    o.width = 1;
+    ASSERT_EQ(0, wcwidth_wrap_u8(" hello", 6, &o, &out, &len));
+    check_lines(out, len, exp, 5);
+    free(out);
+
+    o.width = 1;
+    o.drop_whitespace = false;
+    ASSERT_EQ(0, wcwidth_wrap_u8(" hello", 6, &o, &out, &len));
+    check_lines(out, len, exp_ws, 6);
+    free(out);
+}
+
 int
 main(void)
 {
@@ -301,5 +321,6 @@ main(void)
     RUN_TEST(wrap_tabsize_zero);
     RUN_TEST(wrap_lone_continuation_bytes);
     RUN_TEST(wrap_max_lines_placeholder);
+    RUN_TEST(wrap_drops_leading_whitespace_only_line);
     return test_summary();
 }

tests/test_textwrap.py

@@ -678,3 +678,10 @@ def test_wrap_unterminated_osc():
 def test_wrap_virama_conjunct_known_limitation(text):
     """Known limitation: wrap() breaks mid-conjunct on Tamil, Kannada and Sinhala text."""
     assert [wcwidth.width(line) for line in wrap(text * 4, width=4)] == [3, 4, 3]
+
+
+@pytest.mark.parametrize('text', [' hello', '  hello', '    hello'])
+def test_wrap_drops_leading_whitespace_only_lines(text):
+    """Discard all-whitespace first lines rather than emitting empty lines."""
+    assert wrap(text, width=1) == list('hello')
+    assert wrap(text, width=1, drop_whitespace=False) == list(text)

wcwidth/textwrap.py

@@ -353,6 +353,8 @@ def _wrap_chunks(self, chunks: list[str]) -> list[str]:  # pylint: disable=too-m
                     # (matches CPython #140627 fix behavior)
                     if self.drop_whitespace:
                         line_content = line_content.rstrip()
+                        if not line_content:
+                            continue
                     lines.append(indent + line_content)
                     is_first_line = False
                 else: