[OE-core] [PATCH] classes/reproducible_build: Move SDE deploy to another directory

[Joshua Watt]

The deployment of the source date epoch file had a race condition where
any task attempting to read from the file would race with creation of
the sstate archive for the do_deploy_source_date_epoch task. The
creation of the sstate archive requires moving the directory to a
temporary location, then moving it back. This means that the file
disappears for a short period of time, which will cause a failure if any
other task is running and trying to open the file to get the current
source date epoch.

The solution is to copy the source date epoch file to a separate
directory when deploying so the file never disappears. When the file is
restored from sstate, it is moved to the correct location after being
extracted.

[YOCTO #13501]

Signed-off-by: Joshua Watt <JPEWhacker at gmail.com>
---
 meta/classes/reproducible_build.bbclass | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/meta/classes/reproducible_build.bbclass b/meta/classes/reproducible_build.bbclass
index 8788ad7145c..4753d458b58 100644
--- a/meta/classes/reproducible_build.bbclass
+++ b/meta/classes/reproducible_build.bbclass
@@ -39,19 +39,23 @@ inherit ${@oe.utils.ifelse(d.getVar('BUILD_REPRODUCIBLE_BINARIES') == '1', 'repr
 
 SDE_DIR ="${WORKDIR}/source-date-epoch"
 SDE_FILE = "${SDE_DIR}/__source_date_epoch.txt"
+SDE_DEPLOYDIR = "${WORKDIR}/deploy-source-date-epoch"
 
 SSTATETASKS += "do_deploy_source_date_epoch"
 
 do_deploy_source_date_epoch () {
     echo "Deploying SDE to ${SDE_DIR}."
+    mkdir -p ${SDE_DEPLOYDIR}
+    cp -p ${SDE_FILE} ${SDE_DEPLOYDIR}/__source_date_epoch.txt
 }
 
 python do_deploy_source_date_epoch_setscene () {
     sstate_setscene(d)
+    os.rename(os.path.join(d.getVar('SDE_DEPLOYDIR'), '__source_date_epoch.txt'), d.getVar('SDE_FILE'))
 }
 
-do_deploy_source_date_epoch[dirs] = "${SDE_DIR}"
-do_deploy_source_date_epoch[sstate-plaindirs] = "${SDE_DIR}"
+do_deploy_source_date_epoch[dirs] = "${SDE_DEPLOYDIR}"
+do_deploy_source_date_epoch[sstate-plaindirs] = "${SDE_DEPLOYDIR}"
 addtask do_deploy_source_date_epoch_setscene
 addtask do_deploy_source_date_epoch before do_configure after do_patch
 
-- 
2.21.0