[PATCH 4/4] warn only once in case file timestamps are updated

[Felix Moessbauer <felix.moessbauer@siemens.com>]

When creating a reproducible image, file timestamps of too-new files are
updated in a postprocess step. This includes potentially many files.

Previously, a bitbake warning was filed per single file, which
overflooded the terminal. The new implementation simply prints a summary
and gives a hint where the full list can be found.

Suggested-by: Roberto A. Foglietta <roberto.foglietta@gmail.com>
Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
---
 meta/classes/image.bbclass | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index e59767e7..eb546084 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -447,11 +447,14 @@ EOSUDO
     # Set same time-stamps to the newly generated file/folders in the
     # rootfs image for the purpose of reproducible builds.
     if [ -n "${SOURCE_DATE_EPOCH}" ]; then
-        sudo find ${ROOTFSDIR} -newermt \
-            "$(date -d@${SOURCE_DATE_EPOCH} '+%Y-%m-%d %H:%M:%S')" \
-            -printf "%y %p\n" \
-            -exec touch '{}' -h -d@${SOURCE_DATE_EPOCH} ';' > ${DEPLOY_DIR_IMAGE}/files.modified_timestamps && \
-            bbwarn "$(grep ^f ${DEPLOY_DIR_IMAGE}/files.modified_timestamps) \nModified above file timestamps to build image reproducibly"
+        fn="${DEPLOY_DIR_IMAGE}/files.modified_timestamps"
+        if sudo find ${ROOTFSDIR} -newermt "$(date -d@${SOURCE_DATE_EPOCH} '+%Y-%m-%d %H:%M:%S')" \
+            -printf "%y %p\n" -exec touch '{}' -h -d@${SOURCE_DATE_EPOCH} ';' | egrep ^f >"$fn"; then
+            if [ -e "$fn" ]; then
+                bbwarn "modified timestamp (${SOURCE_DATE_EPOCH}) of $(cat "$fn" | wc -l) files for image reproducibly." \
+                       "List of files modified can be found in: .${DEPLOY_DIR_IMAGE}/files.modified_timestamps"
+            fi
+        fi
     fi
 
 }
-- 
2.34.1