pkg: always rebuilt when patches are applied #13030
Description
Description
Any external package that uses patches is recompiled every time a build is triggered. For some packages, this increases build times unnecessarily.
I believe the problem was introduced by this change/line in pkg/pkg.mk. Applying a patch will result in an additional commit, so $(shell git -C $(PKG_BUILDDIR) rev-parse HEAD) != $(PKG_VERSION) will always be true and the repository is always fetched.
A quick test of #11553 showed that it fixes the problem, but I have little knowledge of Makefiles.
Steps to reproduce the issue
Any package that uses patches is affected. For example, pkg/u8g2.
QUIET=0 make -C tests/pkg_u8g2 clean
QUIET=0 make -C tests/pkg_u8g2
Expected results
After a rebuild, the files of u8g2 are not rebuilt.
Actual results
After an initial compilation, files are still rebuild, because the repository is fetched again.
This shows the relevant part where the repository is checked out again.
...
gmake[1]: Entering directory '/Users/basilfx/Desktop/RIOT_knx/RIOT/pkg/u8g2'
Removing .git-downloaded
Removing .git-patched
Removing Makefile
Removing csrc/Makefile
Removing csrc/u8g2_riotos.c
Removing sys/sdl/common/Makefile
Removing sys/utf8/common/Makefile
touch /Users/basilfx/Desktop/RIOT_knx/RIOT/tests/pkg_u8g2/bin/basilfx-taster/.test
From https://github.com/olikraus/u8g2
* branch f08ff974c03e5c848bc5d2ae3fddb6a97897881a -> FETCH_HEAD
Warning: you are leaving 1 commit behind, not connected to
any of your branches:
03ef9955 add RIOT-OS interface.
If you want to keep it by creating a new branch, this may be a good time
to do so with:
git branch <new-branch-name> 03ef9955
HEAD is now at f08ff974 issue #556
git -C /Users/basilfx/Desktop/RIOT_knx/RIOT/tests/pkg_u8g2/bin/pkg/basilfx-taster/u8g2 checkout -f f08ff974c03e5c848bc5d2ae3fddb6a97897881a
HEAD is now at f08ff974 issue #556
git -c user.email=buildsystem@riot -c user.name="RIOT buildsystem" -C /Users/basilfx/Desktop/RIOT_knx/RIOT/tests/pkg_u8g2/bin/pkg/basilfx-taster/u8g2 am --no-gpg-sign --ignore-whitespace --whitespace=nowarn "/Users/basilfx/Desktop/RIOT_knx/RIOT/pkg/u8g2"/patches/*.patch
Applying: add RIOT-OS interface.
touch /Users/basilfx/Desktop/RIOT_knx/RIOT/tests/pkg_u8g2/bin/pkg/basilfx-taster/u8g2/.git-patched
gmake[1]: Leaving directory '/Users/basilfx/Desktop/RIOT_knx/RIOT/pkg/u8g2'
...
Versions
Operating System Environment
-----------------------------
Operating System: Mac OS X 10.15.2
Kernel: Darwin 19.2.0 x86_64 i386
Installed compiler toolchains
-----------------------------
native gcc: Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
arm-none-eabi-gcc: arm-none-eabi-gcc (GNU Tools for Arm Embedded Processors 9-2019-q4-major) 9.2.1 20191025 (release) [ARM/arm-9-branch revision 277599]
avr-gcc: missing
mips-mti-elf-gcc: missing
msp430-gcc: missing
riscv-none-embed-gcc: missing
xtensa-esp32-elf-gcc: missing
xtensa-lx106-elf-gcc: missing
clang: Apple clang version 11.0.0 (clang-1100.0.33.8)
Installed compiler libs
-----------------------
arm-none-eabi-newlib: "3.1.0"
mips-mti-elf-newlib: missing
riscv-none-embed-newlib: missing
xtensa-esp32-elf-newlib: missing
xtensa-lx106-elf-newlib: missing
avr-libc: missing (missing)
Installed development tools
---------------------------
ccache: missing
cmake: missing
cppcheck: missing
doxygen: missing
git: git version 2.24.1
make: GNU Make 4.2.1
openocd: missing
python: Python 2.7.16
python2: Python 2.7.16
python3: Python 3.7.5
flake8: error: /usr/local/opt/python/bin/python3.7: No module named flake8
coccinelle: missing