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>

diff --git a/meta/classes/reproducible_build.bbclass b/meta/classes/reproducible_build.bbclass
index 89f645b8584ee37a049b97f5aee843e51cd8405f..7571c116c82eb01c04f9d8b44c299b47a09b2b19 100644 (file)
--- a/meta/classes/reproducible_build.bbclass
+++ b/meta/classes/reproducible_build.bbclass
@@ -115,11 +115,14 @@ EPOCHTASK = "do_deploy_source_date_epoch"
 do_unpack[postfuncs] += "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:
@@ -137,7 +140,7 @@ 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)}"