From 30249505267d676767777f033f930184d291e282 Mon Sep 17 00:00:00 2001
From: Ryan Kendra <rkendra@umich.edu>
Date: Thu, 5 Dec 2024 17:09:05 -0500
Subject: [PATCH] Fixed span_range omitting dates when frame is 'month', exact
 is True, and start.day is 31 (#1185)

---
 arrow/arrow.py      | 10 ++++++++++
 tests/test_arrow.py | 16 +++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/arrow/arrow.py b/arrow/arrow.py
index 9d1f5e30..8fbc1e76 100644
--- a/arrow/arrow.py
+++ b/arrow/arrow.py
@@ -699,7 +699,17 @@ def span_range(
                 yield r.span(frame, bounds=bounds, exact=exact)
 
         for r in _range:
+            day_is_clipped = False
             floor, ceil = r.span(frame, bounds=bounds, exact=exact)
+            next = ceil.shift(microseconds=+1)
+            if frame == "month" and next.day < start.day:
+                day_is_clipped = True
+            if day_is_clipped and not next._is_last_day_of_month(next):
+                days_to_shift = (
+                    min(start.day, calendar.monthrange(next.year, next.month)[1])
+                    - next.day
+                )
+                ceil = ceil.shift(days=days_to_shift)
             if ceil > end:
                 ceil = end
                 if bounds[1] == ")":
diff --git a/tests/test_arrow.py b/tests/test_arrow.py
index 086f5cf2..caaf9e51 100644
--- a/tests/test_arrow.py
+++ b/tests/test_arrow.py
@@ -1185,7 +1185,7 @@ def test_month(self):
             (arrow.Arrow(2013, 4, 1), arrow.Arrow(2013, 4, 30, 23, 59, 59, 999999)),
         ]
 
-    def test_month_end(self):
+    def test_month_exact(self):
         result = list(
             arrow.Arrow.span_range(
                 "month", datetime(2013, 1, 31), datetime(2014, 1, 31), exact=True
@@ -1207,6 +1207,20 @@ def test_month_end(self):
             (arrow.Arrow(2013, 12, 31), arrow.Arrow(2014, 1, 30, 23, 59, 59, 999999)),
         ]
 
+    def test_month_exact_leap(self):
+        result = list(
+            arrow.Arrow.span_range(
+                "month", datetime(2012, 1, 31), datetime(2012, 5, 31), exact=True
+            )
+        )
+
+        assert result == [
+            (arrow.Arrow(2012, 1, 31), arrow.Arrow(2012, 2, 28, 23, 59, 59, 999999)),
+            (arrow.Arrow(2012, 2, 29), arrow.Arrow(2012, 3, 30, 23, 59, 59, 999999)),
+            (arrow.Arrow(2012, 3, 31), arrow.Arrow(2012, 4, 29, 23, 59, 59, 999999)),
+            (arrow.Arrow(2012, 4, 30), arrow.Arrow(2012, 5, 30, 23, 59, 59, 999999)),
+        ]
+
     def test_week(self):
         result = list(
             arrow.Arrow.span_range("week", datetime(2013, 2, 2), datetime(2013, 2, 28))