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: Steve Sakoman <steve@sakoman.com>

diff --git a/meta/classes/reproducible_build.bbclass b/meta/classes/reproducible_build.bbclass
index f06e00d70d7eaf0f8ddc3aa6615d79b549e64c94..43cf9dc89410b3ee4d507337fc72d9daa83499ef 100644 (file)
--- a/meta/classes/reproducible_build.bbclass
+++ b/meta/classes/reproducible_build.bbclass
@@ -91,11 +91,14 @@ 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'))
     if os.path.isfile(epochfile):
         with open(epochfile, 'r') as f:
@@ -113,7 +116,7 @@ def get_source_date_epoch_value(d):
     else:
         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)}"