bitbake.conf: Account for older versions of bitbake

Older versions of bitbake (prior to 1.42) don't expose the BB_UNIHASH
variable which is being used by sstate. For compatibility with these
older versions of bitbake, set BB_UNIHASH to BB_TASKHASH (which is the
value it should be for non-hash equivalent aware signature generators).
if bitbake hasn't already set it.

[YOCTO #13314]

(From OE-Core rev: ca38b2f88f640579703486645b0c4d9ecef78e47)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 7f8b043cc4..b4e8990473 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -898,3 +898,9 @@ BB_SIGNATURE_EXCLUDE_FLAGS ?= "doc deps depends \
 
 MLPREFIX ??= ""
 MULTILIB_VARIANTS ??= ""
+
+# Older versions of bitbake (< 1.42) don't set BB_UNIHASH. For compatibility with these
+# versions, set BB_UNIHASH equivalent to BB_TASKHASH if unspecified, which is
+# what it would be anyway if the signature generator (e.g. OEEquivHash) doesn't
+# support unihashes.
+BB_UNIHASH ?= "${BB_TASKHASH}"