From 716e85b42a6a08b3f00fd7cc68f3e05c3dff0e22 Mon Sep 17 00:00:00 2001
From: fan wu <336798967+FanWu-ai@users.noreply.github.com>
Date: Sun, 11 Oct 2026 09:26:21 -0700
Subject: [PATCH] Parse timezone names with multiple slash-separated components

AI assistance: OpenAI Codex was used for investigation, implementation, regression tests, and automated validation.
---
 docs/docs/instantiation.md           |  8 +++++
 src/pendulum/formatting/formatter.py |  2 +-
 tests/datetime/test_from_format.py   | 46 ++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/docs/docs/instantiation.md b/docs/docs/instantiation.md
index a49c6a26c..23aa5bd2c 100644
--- a/docs/docs/instantiation.md
+++ b/docs/docs/instantiation.md
@@ -119,6 +119,14 @@ It also accepts a `tz` keyword argument to specify the timezone:
 '1975-05-21T22:00:00+01:00'
 ```
 
+Use the `z` token to read a timezone name from the input, including names with multiple slashes:
+
+```python
+>>> dt = pendulum.from_format('2024-01-15 America/Argentina/Buenos_Aires', 'YYYY-MM-DD z')
+>>> dt.timezone_name
+'America/Argentina/Buenos_Aires'
+```
+
 The final helper is for working with unix timestamps.
 `from_timestamp()` will create a `DateTime` instance equal to the given timestamp
 and will set the timezone as well or default it to `UTC`.
diff --git a/src/pendulum/formatting/formatter.py b/src/pendulum/formatting/formatter.py
index b09977d0d..600bd3473 100644
--- a/src/pendulum/formatting/formatter.py
+++ b/src/pendulum/formatting/formatter.py
@@ -42,7 +42,7 @@
     "['a-z\u00a0-\u05ff\u0700-\ud7ff\uf900-\ufdcf\ufdf0-\uffef]+"
     r"|[\u0600-\u06FF/]+(\s*?[\u0600-\u06FF]+){1,2}"
 )
-_MATCH_TIMEZONE = "[A-Za-z0-9-+]+(/[A-Za-z0-9-+_]+)?"
+_MATCH_TIMEZONE = "[A-Za-z0-9-+]+(/[A-Za-z0-9-+_]+)*"
 
 
 class Formatter:
diff --git a/tests/datetime/test_from_format.py b/tests/datetime/test_from_format.py
index ecf59632a..362f69c45 100644
--- a/tests/datetime/test_from_format.py
+++ b/tests/datetime/test_from_format.py
@@ -45,6 +45,52 @@ def test_from_format_with_square_bracket_in_timezone():
         )
 
 
+@pytest.mark.parametrize(
+    "zone",
+    [
+        "America/Argentina/Buenos_Aires",
+        "America/Indiana/Indianapolis",
+        "America/Kentucky/Louisville",
+        "America/North_Dakota/New_Salem",
+        "Europe/Paris",
+        "UTC",
+    ],
+)
+@pytest.mark.parametrize("month", [1, 7])
+@pytest.mark.parametrize(
+    "fmt",
+    [
+        "YYYY-MM-DD HH:mm:ss.SSSSSS z",
+        "z YYYY-MM-DD HH:mm:ss.SSSSSS",
+        "z/YYYY-MM-DD HH:mm:ss.SSSSSS",
+    ],
+)
+def test_from_format_with_nested_timezone(zone: str, month: int, fmt: str) -> None:
+    expected = pendulum.datetime(2024, month, 15, 12, 34, 56, 123456, tz=zone)
+
+    actual = pendulum.from_format(expected.format(fmt), fmt, tz="Europe/London")
+
+    assert actual == expected
+    assert actual.timezone_name == zone
+    assert actual.utcoffset() == expected.utcoffset()
+
+
+@pytest.mark.parametrize(
+    "zone",
+    [
+        "America/Argentina/Not_A_City",
+        "America/Argentina/Buenos_Aires/Extra",
+        "America//Argentina/Buenos_Aires",
+        "America/Argentina/Buenos_Aires/",
+        "/America/Argentina/Buenos_Aires",
+        "America/Argentina/Buenos_Aires extra",
+    ],
+)
+def test_from_format_rejects_invalid_nested_timezone(zone: str) -> None:
+    with pytest.raises(ValueError):
+        pendulum.from_format(f"2024-01-15 12:34:56 {zone}", "YYYY-MM-DD HH:mm:ss z")
+
+
 def test_from_format_with_escaped_elements():
     d = pendulum.from_format("1975-05-21T22:32:11+00:00", "YYYY-MM-DD[T]HH:mm:ssZ")
     assert_datetime(d, 1975, 5, 21, 22, 32, 11)