reproducible_build: Work around caching issues

SOURCE_DATE_EPOCH can be expanded early in the parsing process before
the class extensions are applied. This can mean the directory pointed
to for the SDE can be incorrect until later in parsing. Cache the file
name in the cached value and allow it to dynamically update.

This isn't ideal but avoding expansion of the variable likely isn't
possible and I'm not sure how else to handle this. This works around
the issue until a better solution can be found.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 44dc97cd1223e4d2b635669627ec5f796838d42d)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>

diff --git a/meta/classes/reproducible_build.bbclass b/meta/classes/reproducible_build.bbclass
index 1277764faba9591b622c885ec9b329b22115ad86..62655c2a5bcd47cdd72897d0cf2ce3ce45089662 100644 (file)
--- a/meta/classes/reproducible_build.bbclass
+++ b/meta/classes/reproducible_build.bbclass
@@ -90,11 +90,14 @@ python create_source_date_epoch_stamp() {
 }
 
 def get_source_date_epoch_value(d):
-    cached = d.getVar('__CACHED_SOURCE_DATE_EPOCH')
-    if cached:
+    epochfile = d.getVar('SDE_FILE')
+    cached, efile = d.getVar('__CACHED_SOURCE_DATE_EPOCH') or (None, None)
+    if cached and efile == epochfile:
         return cached
 
-    epochfile = d.getVar('SDE_FILE')
+    if cached and epochfile != efile:
+        bb.debug(1, "Epoch file changed from %s to %s" % (efile, epochfile))
+
     source_date_epoch = int(d.getVar('SOURCE_DATE_EPOCH_FALLBACK'))
     try:
         with open(epochfile, 'r') as f:
@@ -112,7 +115,7 @@ def get_source_date_epoch_value(d):
     except FileNotFoundError:
         bb.debug(1, "Cannot find %s. SOURCE_DATE_EPOCH will default to %d" % (epochfile, source_date_epoch))
 
-    d.setVar('__CACHED_SOURCE_DATE_EPOCH', str(source_date_epoch))
+    d.setVar('__CACHED_SOURCE_DATE_EPOCH', (str(source_date_epoch), epochfile))
     return str(source_date_epoch)
 
 export SOURCE_DATE_EPOCH ?= "${@get_source_date_epoch_value(d)}"