From 588916a66405880aa9ff55cefa7df92abe0af6fc Mon Sep 17 00:00:00 2001
From: Hrishi Shinde <hrishi.shinde.20@gmail.com>
Date: Thu, 16 Apr 2026 17:40:35 -0500
Subject: [PATCH 1/2] GH-49719: [C++] Rename vendored date header guards

Prefix all header guards in the vendored date library with
ARROW_VENDORED_ to avoid collisions when a project also uses
the real date library. Update update.sh to apply the same
rewrite automatically on future re-vendoring.
---
 cpp/src/arrow/vendored/datetime/date.h       | 6 +++---
 cpp/src/arrow/vendored/datetime/ios.h        | 6 +++---
 cpp/src/arrow/vendored/datetime/tz.h         | 6 +++---
 cpp/src/arrow/vendored/datetime/tz_private.h | 6 +++---
 cpp/src/arrow/vendored/datetime/update.sh    | 6 ++++++
 5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/cpp/src/arrow/vendored/datetime/date.h b/cpp/src/arrow/vendored/datetime/date.h
index 1b06182a6da..5e0ff852462 100644
--- a/cpp/src/arrow/vendored/datetime/date.h
+++ b/cpp/src/arrow/vendored/datetime/date.h
@@ -1,5 +1,5 @@
-#ifndef DATE_H
-#define DATE_H
+#ifndef ARROW_VENDORED_DATE_H
+#define ARROW_VENDORED_DATE_H
 
 // The MIT License (MIT)
 //
@@ -8242,4 +8242,4 @@ operator<<(std::basic_ostream<CharT, Traits>& os,
 # pragma GCC diagnostic pop
 #endif
 
-#endif  // DATE_H
+#endif  // ARROW_VENDORED_DATE_H
diff --git a/cpp/src/arrow/vendored/datetime/ios.h b/cpp/src/arrow/vendored/datetime/ios.h
index d018e799a83..ee341fd7784 100644
--- a/cpp/src/arrow/vendored/datetime/ios.h
+++ b/cpp/src/arrow/vendored/datetime/ios.h
@@ -24,8 +24,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#ifndef ios_hpp
-#define ios_hpp
+#ifndef ARROW_VENDORED_ios_hpp
+#define ARROW_VENDORED_ios_hpp
 
 #if __APPLE__
 # include <TargetConditionals.h>
@@ -47,4 +47,4 @@
 #else   // !__APPLE__
 # define TARGET_OS_IPHONE 0
 #endif  // !__APPLE__
-#endif // ios_hpp
+#endif // ARROW_VENDORED_ios_hpp
diff --git a/cpp/src/arrow/vendored/datetime/tz.h b/cpp/src/arrow/vendored/datetime/tz.h
index 61ab3df106d..151a67fe904 100644
--- a/cpp/src/arrow/vendored/datetime/tz.h
+++ b/cpp/src/arrow/vendored/datetime/tz.h
@@ -1,5 +1,5 @@
-#ifndef TZ_H
-#define TZ_H
+#ifndef ARROW_VENDORED_TZ_H
+#define ARROW_VENDORED_TZ_H
 
 // The MIT License (MIT)
 //
@@ -2805,4 +2805,4 @@ to_gps_time(const tai_time<Duration>& t)
 
 }  // namespace arrow_vendored::date
 
-#endif  // TZ_H
+#endif  // ARROW_VENDORED_TZ_H
diff --git a/cpp/src/arrow/vendored/datetime/tz_private.h b/cpp/src/arrow/vendored/datetime/tz_private.h
index 1d7f8589711..39059a1a4ae 100644
--- a/cpp/src/arrow/vendored/datetime/tz_private.h
+++ b/cpp/src/arrow/vendored/datetime/tz_private.h
@@ -1,5 +1,5 @@
-#ifndef TZ_PRIVATE_H
-#define TZ_PRIVATE_H
+#ifndef ARROW_VENDORED_TZ_PRIVATE_H
+#define ARROW_VENDORED_TZ_PRIVATE_H
 
 // The MIT License (MIT)
 //
@@ -312,4 +312,4 @@ struct transition
 #include "tz.h"
 #endif
 
-#endif  // TZ_PRIVATE_H
+#endif  // ARROW_VENDORED_TZ_PRIVATE_H
diff --git a/cpp/src/arrow/vendored/datetime/update.sh b/cpp/src/arrow/vendored/datetime/update.sh
index b4580c04260..b65ae4901d7 100755
--- a/cpp/src/arrow/vendored/datetime/update.sh
+++ b/cpp/src/arrow/vendored/datetime/update.sh
@@ -46,6 +46,12 @@ sed -i.bak -E \
     -e 's/namespace date/namespace arrow_vendored::date/g' \
     -e 's,include "date/,include ",g' \
     *.{cpp,h,mm}
+sed -i.bak -E \
+    -e 's/(#ifndef |#define |#endif.*\/\/ )(DATE_H)/\1ARROW_VENDORED_\2/g' \
+    -e 's/(#ifndef |#define |#endif.*\/\/ )(ios_hpp)/\1ARROW_VENDORED_\2/g' \
+    -e 's/(#ifndef |#define |#endif.*\/\/ )(TZ_H)/\1ARROW_VENDORED_\2/g' \
+    -e 's/(#ifndef |#define |#endif.*\/\/ )(TZ_PRIVATE_H)/\1ARROW_VENDORED_\2/g' \
+    *.h
 sed -i.bak -E \
     -e "s/changeset [0-9a-f]+/changeset ${commit_id}/g" \
     README.md

From 645181c4b5a4574dae6a9618706f9376b588e685 Mon Sep 17 00:00:00 2001
From: Hrishi Shinde <hrishi.shinde.20@gmail.com>
Date: Thu, 16 Apr 2026 20:53:05 -0500
Subject: [PATCH 2/2] stricter regex and unify sed commands

---
 cpp/src/arrow/vendored/datetime/update.sh | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/cpp/src/arrow/vendored/datetime/update.sh b/cpp/src/arrow/vendored/datetime/update.sh
index b65ae4901d7..7ee60fc7af3 100755
--- a/cpp/src/arrow/vendored/datetime/update.sh
+++ b/cpp/src/arrow/vendored/datetime/update.sh
@@ -47,10 +47,7 @@ sed -i.bak -E \
     -e 's,include "date/,include ",g' \
     *.{cpp,h,mm}
 sed -i.bak -E \
-    -e 's/(#ifndef |#define |#endif.*\/\/ )(DATE_H)/\1ARROW_VENDORED_\2/g' \
-    -e 's/(#ifndef |#define |#endif.*\/\/ )(ios_hpp)/\1ARROW_VENDORED_\2/g' \
-    -e 's/(#ifndef |#define |#endif.*\/\/ )(TZ_H)/\1ARROW_VENDORED_\2/g' \
-    -e 's/(#ifndef |#define |#endif.*\/\/ )(TZ_PRIVATE_H)/\1ARROW_VENDORED_\2/g' \
+    -e 's/(#ifndef |#define |#endif *\/\/ )(DATE_H|ios_hpp|TZ_H|TZ_PRIVATE_H)/\1ARROW_VENDORED_\2/g' \
     *.h
 sed -i.bak -E \
     -e "s/changeset [0-9a-f]+/changeset ${commit_id}/g" \