From 4722fb991bde7af77fd59bb5729ca550ab357963 Mon Sep 17 00:00:00 2001
From: Hiroyuki Sato <hiroysato@gmail.com>
Date: Thu, 20 Aug 2026 13:56:24 +0900
Subject: [PATCH 1/2] GH-50917: [C++] Fix shellcheck errors in
 cpp/build-support/*-flatbuffers.sh

---
 .pre-commit-config.yaml                 |  2 ++
 cpp/build-support/update-flatbuffers.sh | 11 ++++++++---
 cpp/build-support/vendor-flatbuffers.sh |  8 ++++----
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 9a38aef88d0f..128d5fbca11e 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -296,7 +296,9 @@ repos:
           ?^cpp/build-support/build-lz4-lib\.sh$|
           ?^cpp/build-support/build-zstd-lib\.sh$|
           ?^cpp/build-support/get-upstream-commit\.sh$|
+          ?^cpp/build-support/update-flatbuffers\.sh$|
           ?^cpp/build-support/update-thrift\.sh$|
+          ?^cpp/build-support/vendor-flatbuffers\.sh$|
           ?^cpp/examples/minimal_build/run\.sh$|
           ?^cpp/examples/tutorial_examples/run\.sh$|
           ?^cpp/src/arrow/flight/sql/odbc/install/mac/postinstall$|
diff --git a/cpp/build-support/update-flatbuffers.sh b/cpp/build-support/update-flatbuffers.sh
index 6738f81a5605..0e6efb757e08 100755
--- a/cpp/build-support/update-flatbuffers.sh
+++ b/cpp/build-support/update-flatbuffers.sh
@@ -24,13 +24,18 @@ set -euo pipefail
 
 CWD="$(cd "$(dirname "${BASH_SOURCE[0]:-$0}")" && pwd)"
 SOURCE_DIR="$CWD/../src"
-PYTHON_SOURCE_DIR="$CWD/../../python"
+#PYTHON_SOURCE_DIR="$CWD/../../python" # Unused ShellCheck (SC2034)
 FORMAT_DIR="$CWD/../../format"
-TOP="$FORMAT_DIR/.."
+#TOP="$FORMAT_DIR/.." # Unused ShellCheck (SC2034)
 FLATC="flatc --cpp --cpp-std c++11 --scoped-enums"
 
 OUT_DIR="$SOURCE_DIR/generated"
-FILES=($(find $FORMAT_DIR -name '*.fbs'))
+# Avoid word splitting (SC2207) while maintaining Bash 3 compatibility.
+# See: https://www.shellcheck.net/wiki/SC2207
+FILES=()
+while IFS= read -r file; do
+  FILES+=("$file")
+done < <(find "$FORMAT_DIR" -name '*.fbs')
 FILES+=("$SOURCE_DIR/arrow/ipc/feather.fbs")
 
 $FLATC -o "$OUT_DIR" "${FILES[@]}"
diff --git a/cpp/build-support/vendor-flatbuffers.sh b/cpp/build-support/vendor-flatbuffers.sh
index 6cbf77b9ca5f..30ebbcedbf28 100755
--- a/cpp/build-support/vendor-flatbuffers.sh
+++ b/cpp/build-support/vendor-flatbuffers.sh
@@ -25,7 +25,7 @@ set -eu
 SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]:-$0}")" && pwd)"
 
 VENDOR_LOCATION=$SOURCE_DIR/../thirdparty/flatbuffers/include/flatbuffers
-mkdir -p $VENDOR_LOCATION
-cp -f $FLATBUFFERS_HOME/include/flatbuffers/base.h $VENDOR_LOCATION
-cp -f $FLATBUFFERS_HOME/include/flatbuffers/flatbuffers.h $VENDOR_LOCATION
-cp -f $FLATBUFFERS_HOME/include/flatbuffers/stl_emulation.h $VENDOR_LOCATION
+mkdir -p "$VENDOR_LOCATION"
+cp -f "$FLATBUFFERS_HOME/include/flatbuffers/base.h" "$VENDOR_LOCATION"
+cp -f "$FLATBUFFERS_HOME/include/flatbuffers/flatbuffers.h" "$VENDOR_LOCATION"
+cp -f "$FLATBUFFERS_HOME/include/flatbuffers/stl_emulation.h" "$VENDOR_LOCATION"

From 3342f4e4bb3ea9e809d00761a8cd6dc44db272c2 Mon Sep 17 00:00:00 2001
From: Hiroyuki Sato <hiroysato@gmail.com>
Date: Thu, 20 Aug 2026 16:42:01 +0900
Subject: [PATCH 2/2] GH-50917: [C++] Remove unused variables

---
 cpp/build-support/update-flatbuffers.sh | 2 --
 1 file changed, 2 deletions(-)

diff --git a/cpp/build-support/update-flatbuffers.sh b/cpp/build-support/update-flatbuffers.sh
index 0e6efb757e08..691d01909147 100755
--- a/cpp/build-support/update-flatbuffers.sh
+++ b/cpp/build-support/update-flatbuffers.sh
@@ -24,9 +24,7 @@ set -euo pipefail
 
 CWD="$(cd "$(dirname "${BASH_SOURCE[0]:-$0}")" && pwd)"
 SOURCE_DIR="$CWD/../src"
-#PYTHON_SOURCE_DIR="$CWD/../../python" # Unused ShellCheck (SC2034)
 FORMAT_DIR="$CWD/../../format"
-#TOP="$FORMAT_DIR/.." # Unused ShellCheck (SC2034)
 FLATC="flatc --cpp --cpp-std c++11 --scoped-enums"
 
 OUT_DIR="$SOURCE_DIR/generated"