_artifactcache: Add key parameter to push_needed() method

Contain cache key logic in Element class.

3 files changed, 10 insertions, 7 deletions

diff --git a/buildstream/_artifactcache/artifactcache.py b/buildstream/_artifactcache/artifactcache.py
index 0bbb05255..da6bed5d6 100644
--- a/buildstream/_artifactcache/artifactcache.py
+++ b/buildstream/_artifactcache/artifactcache.py
@@ -238,10 +238,11 @@ class ArtifactCache():
     #
     # Args:
     #     element (Element): The Element to check
+    #     key (str): The cache key to use
     #
     # Returns: False if all the push remotes have the artifact, True otherwise
     #
-    def push_needed(self, element):
+    def push_needed(self, element, key):
         return False
 
     # push():
diff --git a/buildstream/_artifactcache/ostreecache.py b/buildstream/_artifactcache/ostreecache.py
index 6a7ee2a46..4676e43d6 100644
--- a/buildstream/_artifactcache/ostreecache.py
+++ b/buildstream/_artifactcache/ostreecache.py
@@ -189,14 +189,11 @@ class OSTreeCache(ArtifactCache):
     #
     # Args:
     #     element (Element): The Element to check
+    #     key (str): The cache key to use
     #
     # Returns: False if all the push remotes have the artifact, True otherwise
     #
-    def push_needed(self, element):
-        key = element._get_cache_key(strength=_KeyStrength.STRONG)
-
-        if not key:
-            return False
+    def push_needed(self, element, key):
 
         remotes_with_artifact = self.remotes_containing_key(element, key)
 
diff --git a/buildstream/element.py b/buildstream/element.py
index 86bdb248b..433521329 100644
--- a/buildstream/element.py
+++ b/buildstream/element.py
@@ -1160,8 +1160,13 @@ class Element(Plugin):
         if self._tainted():
             return True
 
+        # Use the strong cache key to check whether a remote already has the artifact.
+        # In non-strict mode we want to push updated artifacts even if the
+        # remote already has an artifact with the same weak cache key.
+        key = self._get_cache_key(strength=_KeyStrength.STRONG)
+
         # Skip if every push remote contains this element already.
-        if self.__artifacts.push_needed(self):
+        if self.__artifacts.push_needed(self, key):
             return False
         else:
             return True