From 298337a973229f59adf6b126b27fb7937640ad16 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Wed, 2 Sep 2026 15:33:27 +0200
Subject: [PATCH 1/2] GH-51138: [Python] Fix ccache efficiency

---
 ci/scripts/python_build.sh |  2 +-
 python/CMakeLists.txt      | 13 ++++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/ci/scripts/python_build.sh b/ci/scripts/python_build.sh
index f8c1af3982dd..50fb37db1f19 100755
--- a/ci/scripts/python_build.sh
+++ b/ci/scripts/python_build.sh
@@ -89,7 +89,7 @@ cp -aL "${source_dir}" "${python_build_dir}"
 pushd "${python_build_dir}"
 # - Cannot use build isolation as we want to use specific dependency versions
 #   (e.g. Numpy, Pandas) on some CI jobs.
-${PYTHON:-python} -m pip install --no-deps --no-build-isolation -vv -C cmake.build-type="${CMAKE_BUILD_TYPE:-Debug}" .
+time ${PYTHON:-python} -m pip install --no-deps --no-build-isolation -vv -C cmake.build-type="${CMAKE_BUILD_TYPE:-Debug}" .
 popd
 
 if [ "${BUILD_DOCS_PYTHON}" == "ON" ]; then
diff --git a/python/CMakeLists.txt b/python/CMakeLists.txt
index 4bea6e7d8d40..40aa62c79898 100644
--- a/python/CMakeLists.txt
+++ b/python/CMakeLists.txt
@@ -130,11 +130,14 @@ if(CCACHE_FOUND
    AND NOT CMAKE_C_COMPILER_LAUNCHER
    AND NOT CMAKE_CXX_COMPILER_LAUNCHER)
   message(STATUS "Using ccache: ${CCACHE_FOUND}")
-  set(CMAKE_C_COMPILER_LAUNCHER ${CCACHE_FOUND})
-  set(CMAKE_CXX_COMPILER_LAUNCHER ${CCACHE_FOUND})
-  # ARROW-3985: let ccache preserve C++ comments, because some of them may be
-  # meaningful to the compiler
-  set(ENV{CCACHE_COMMENTS} "1")
+  # 1. Let ccache preserve C++ comments, because some of them may be
+  #    meaningful to the compiler (ARROW-3985)
+  # 2. Set ccache base_dir to the build output directory as it is typically
+  #    a temporary directory, and would otherwise fail caching because of
+  #    using different paths everytime.
+  set(ccache_command ${CCACHE_FOUND} keep_comments_cpp=true base_dir=${CMAKE_BINARY_DIR})
+  set(CMAKE_C_COMPILER_LAUNCHER ${ccache_command})
+  set(CMAKE_CXX_COMPILER_LAUNCHER ${ccache_command})
 endif()
 
 #

From a1df242910ff6328a6e718fe42a0a668a63c5e13 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <antoine@python.org>
Date: Thu, 3 Sep 2026 10:33:19 +0200
Subject: [PATCH 2/2] Use `cmake -E env` to set ccache configuration options

---
 python/CMakeLists.txt | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/python/CMakeLists.txt b/python/CMakeLists.txt
index 40aa62c79898..8eae91e0ed19 100644
--- a/python/CMakeLists.txt
+++ b/python/CMakeLists.txt
@@ -135,7 +135,11 @@ if(CCACHE_FOUND
   # 2. Set ccache base_dir to the build output directory as it is typically
   #    a temporary directory, and would otherwise fail caching because of
   #    using different paths everytime.
-  set(ccache_command ${CCACHE_FOUND} keep_comments_cpp=true base_dir=${CMAKE_BINARY_DIR})
+  # Also, we use `cmake -E env` to set environment variables as the
+  # `ccache option=value ...` form of passing configuration options
+  # is not supported by ccache < 4.8.
+  set(ccache_command ${CMAKE_COMMAND} -E env CCACHE_COMMENTS=1
+                     CCACHE_BASEDIR=${CMAKE_BINARY_DIR} -- ${CCACHE_FOUND})
   set(CMAKE_C_COMPILER_LAUNCHER ${ccache_command})
   set(CMAKE_CXX_COMPILER_LAUNCHER ${ccache_command})
 endif()