classes/native: Propagate dependencies to outhash

Native task outputs are directly run on the build system during the build
after being built. Even if the output of a native recipe doesn't change, a
change in one of its dependencies may cause a change in the output it
generates (e.g. rpm output depends on the output of its dependent zstd
library).

This can cause poor interactions with hash equivalence, since this
recipe's output-changing dependency is "hidden" and downstream tasks only
see that this recipe has the same outhash and therefore is equivalent.
This can result in different output in different cases and issues with
reproducible builds in parcular (e.g. rpm compression changes for the same
content).

To resolve this, unhide the output-changing dependency by adding it's
unihash to this tasks outhash calculation. Unfortunately, we don't know
specifically know which dependencies are output-changing, so we have to
add all of them.

[YOCTO #14685]

(From OE-Core rev: d6c7b9f4f0e61fa6546d3644e27abe3e96f597e2)

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

1 files changed, 31 insertions, 0 deletions

diff --git a/meta/classes/native.bbclass b/meta/classes/native.bbclass
index 76a599bc15..fc7422c5d7 100644
--- a/meta/classes/native.bbclass
+++ b/meta/classes/native.bbclass
@@ -195,3 +195,34 @@ USE_NLS = "no"
 
 RECIPERDEPTASK = "do_populate_sysroot"
 do_populate_sysroot[rdeptask] = "${RECIPERDEPTASK}"
+
+#
+# Native task outputs are directly run on the target (host) system after being
+# built. Even if the output of this recipe doesn't change, a change in one of
+# its dependencies may cause a change in the output it generates (e.g. rpm
+# output depends on the output of its dependent zstd library).
+#
+# This can cause poor interactions with hash equivalence, since this recipes
+# output-changing dependency is "hidden" and downstream task only see that this
+# recipe has the same outhash and therefore is equivalent. This can result in
+# different output in different cases.
+#
+# To resolve this, unhide the output-changing dependency by adding its unihash
+# to this tasks outhash calculation. Unfortunately, don't know specifically
+# know which dependencies are output-changing, so we have to add all of them.
+#
+python native_add_do_populate_sysroot_deps () {
+    current_task = "do_" + d.getVar("BB_CURRENTTASK")
+    if current_task != "do_populate_sysroot":
+        return
+
+    taskdepdata = d.getVar("BB_TASKDEPDATA", False)
+    pn = d.getVar("PN")
+    deps = {
+        dep[0]:dep[6] for dep in taskdepdata.values() if
+            dep[1] == current_task and dep[0] != pn
+    }
+
+    d.setVar("HASHEQUIV_EXTRA_SIGDATA", "\n".join("%s: %s" % (k, deps[k]) for k in sorted(deps.keys())))
+}
+SSTATECREATEFUNCS += "native_add_do_populate_sysroot_deps"