[Buildroot] [PATCH v5 06/19] python2: generate reproducible .pyc

[Jérôme Pouiller]

.pyc files contain modification time of .py source. In order to make
build reproducible, we fix modification time of all .py before compiling .pyc
files.

In add, since pycompile rely on modification times to know if a file need to be
recompiled, it is safer to force recompilation of all source files.

This work was sponsored by `BA Robotic Systems'.

Signed-off-by: Jérôme Pouiller <jezz at sysmic.org>
---

Notes:
    v5:
      - Typo in commit log
      - Explain why we pass --force to pycompile
      - Fix indent
    v3:
      - Force compilation instead of removing .pyc

 package/python/python.mk | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/package/python/python.mk b/package/python/python.mk
index cfd5a0a..cbe7c19 100644
--- a/package/python/python.mk
+++ b/package/python/python.mk
@@ -233,10 +233,18 @@ PYTHON_PATH = $(TARGET_DIR)/usr/lib/python$(PYTHON_VERSION_MAJOR)/sysconfigdata/
 $(eval $(autotools-package))
 $(eval $(host-autotools-package))
 
+ifeq ($(BR2_REPRODUCIBLE),y)
+define PYTHON_FIX_TIME
+	find $(TARGET_DIR)/usr/lib/python$(PYTHON_VERSION_MAJOR) -name '*.py' -print0 | \
+		xargs -0 --no-run-if-empty touch -d @$(SOURCE_DATE_EPOCH)
+endef
+PYTHON_TARGET_FINALIZE_HOOKS += PYTHON_FIX_TIME
+endif
+
 define PYTHON_CREATE_PYC_FILES
 	PYTHONPATH="$(PYTHON_PATH)" \
 	$(HOST_DIR)/usr/bin/python$(PYTHON_VERSION_MAJOR) \
-		support/scripts/pycompile.py \
+		support/scripts/pycompile.py $(if $(BR2_REPRODUCIBLE),--force) \
 		$(TARGET_DIR)/usr/lib/python$(PYTHON_VERSION_MAJOR)
 endef
 
-- 
1.9.1