From 9e313b14e684bf7c9a12e989c2330f7533650cda Mon Sep 17 00:00:00 2001
From: Brandon Maier <brandon.maier@gmail.com>
Date: Sun, 23 Jun 2024 16:29:01 -0500
Subject: [PATCH] pylibfdt/meson.build: fix Python library being rebuilt during
 install

User @sharkcz noted that when the '--quiet' flag is removed from
./setup.py, the following can be seen from the `./setup.py install`
stage.

  Running custom install script 'dtc/g/pylibfdt/../setup.py --top-builddir \
    dtc/g/redhat-linux-build install --prefix=/usr/local --root=$DESTDIR'
  running install
  ...
  building '_libfdt' extension
  swigging dtc/g/pylibfdt/../pylibfdt/libfdt.i to \
    dtc/g/pylibfdt/../pylibfdt/libfdt_wrap.c
  swig -python -Idtc/g/pylibfdt/../libfdt -o \
    dtc/g/pylibfdt/../pylibfdt/libfdt_wrap.c dtc/g/pylibfdt/../pylibfdt/libfdt.i
  gcc -fno-strict-overflow -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 \
    -DNDEBUG -fexceptions -fexceptions -fexceptions -fPIC -DPY_SSIZE_T_CLEAN \
    -Idtc/g/pylibfdt/../libfdt -I/usr/include/python3.12 -c \
    dtc/g/pylibfdt/../pylibfdt/libfdt_wrap.c -o \
    build/temp.linux-ppc64le-cpython-312dtc/g/pylibfdt/../pylibfdt/libfdt_wrap.o
  creating build/lib.linux-ppc64le-cpython-312
  gcc -shared build/temp.linux-ppc64le-cpython-312dtc/g/pylibfdt/../pylibfdt/libfdt_wrap.o \
    -Ldtc/g/redhat-linux-build/libfdt -L/usr/lib64 -lfdt -o \
    build/lib.linux-ppc64le-cpython-312/_libfdt.cpython-312-powerpc64le-linux-gnu.so
  copying dtc/g/pylibfdt/../pylibfdt/libfdt.py -> build/lib.linux-ppc64le-cpython-312

Meaning the python library is getting recompiled during the `meson
install` phase. This causes build issues as Meson does not set the
compiler and linker flags during the install phase.

The reason the library is getting rebuilt is during the normal build
with "build_ext", the `--build-lib` flag gets passed which changes the
default output build directory. But there is no equivalent option for
the "install" command. Install instead looks in the default directory
"./build" and so does not find the previously built library.

Since we can't fix the "install" command, drop the --build-lib flag.
This causes setup.py to compile the libraries at
`<meson-build>/build/lib.linux-x86_64-cpython-312/`. We must also then
fix run_tests.sh to find the library build directory as it's
machine-dependent.

Fixes: #135
Signed-off-by: Brandon Maier <brandon.maier@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 pylibfdt/meson.build |  2 +-
 tests/run_tests.sh   | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/pylibfdt/meson.build b/pylibfdt/meson.build
index 978c53f..6157f8d 100644
--- a/pylibfdt/meson.build
+++ b/pylibfdt/meson.build
@@ -6,7 +6,7 @@ pylibfdt = custom_target(
   input: 'libfdt.i',
   depends: libfdt,
   output: '_libfdt.so',
-  command: [setup_py, 'build_ext', '--build-lib=' + meson.current_build_dir()],
+  command: [setup_py, 'build_ext'],
   build_by_default: true,
 )
 
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index c5d6a88..937b128 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -18,7 +18,9 @@ if [ -n "$NO_PYTHON" ]; then
         no_python=false
     fi
 else
-    if [ -f ../pylibfdt/_libfdt.so ] || [ -f ../pylibfdt/_libfdt.cpython-3*.so ]; then
+    if [ -f ../pylibfdt/_libfdt.so ] \
+            || [ -f ../pylibfdt/_libfdt.cpython-3*.so ] \
+            || [ -f ../build/lib.*/_libfdt.cpython-3*.so ]; then
         no_python=false
     else
         no_python=true
@@ -61,6 +63,16 @@ else
     export LD_LIBRARY_PATH="$TEST_LIBDIR"
 fi
 
+# Find the python module that distutils builds under a machine-specific path
+PYLIBFDT_BUILD=$(echo ../build/lib.*)
+if [ -e "$PYLIBFDT_BUILD" ]; then
+    if [ -n "$PYTHONPATH" ]; then
+        export PYTHONPATH="$PYTHONPATH:$PYLIBFDT_BUILD"
+    else
+        export PYTHONPATH="$PYLIBFDT_BUILD"
+    fi
+fi
+
 export QUIET_TEST=1
 STOP_ON_FAIL=0