From 13599d07e83f5bf6b346158071d76153c5752946 Mon Sep 17 00:00:00 2001
From: 72004 <syahra2014@gmail.com>
Date: Sat, 7 Nov 2026 15:05:18 +0500
Subject: [PATCH] fix: handle indefinite Range bound of 0 in normalize

_get_allele_location_pos picked the defined bound of an indefinite Range
with `pos.root[0] or pos.root[1]`, so a bound of 0 (e.g. Range([0, None]))
was treated as missing and val became None, which made normalize() raise
a TypeError. Pick the defined side explicitly instead.
---
 src/ga4gh/vrs/normalize.py  |  2 +-
 tests/test_vrs_normalize.py | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/ga4gh/vrs/normalize.py b/src/ga4gh/vrs/normalize.py
index 9747febd..0ee08b74 100644
--- a/src/ga4gh/vrs/normalize.py
+++ b/src/ga4gh/vrs/normalize.py
@@ -58,7 +58,7 @@ def _get_allele_location_pos(
         if not pos0_is_none and not pos1_is_none:  # definite range
             return None
 
-        val = pos.root[0] or pos.root[1]
+        val = pos.root[1] if pos0_is_none else pos.root[0]
         pos_type = (
             PosType.RANGE_LT_OR_EQUAL if pos0_is_none else PosType.RANGE_GT_OR_EQUAL
         )
diff --git a/tests/test_vrs_normalize.py b/tests/test_vrs_normalize.py
index d6f62545..860c6a7b 100644
--- a/tests/test_vrs_normalize.py
+++ b/tests/test_vrs_normalize.py
@@ -966,6 +966,23 @@ def _bounds_allele(
         "expected_start": [None, 4400],
         "expected_end": [4501, None],
     },
+    # a defined range bound of 0 must not be mistaken for the undefined one
+    {
+        "id": "indefinite-start-range-from-zero",
+        "start": [0, None],
+        "end": 1,
+        "sequence": "T",
+        "expected_start": [0, None],
+        "expected_end": 1,
+    },
+    {
+        "id": "indefinite-end-range-from-zero",
+        "start": [None, 0],
+        "end": [0, None],
+        "sequence": "A",
+        "expected_start": [None, 0],
+        "expected_end": [0, None],
+    },
 ]