unsupported cache-to must not fail compose build

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
compose-spec · Mar 1, 2022 · 60939c6 · 60939c6
1 parent 1d52804
commit 60939c6
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/build.md b/build.md
@@ -161,7 +161,7 @@ args:
 
 Cache location syntax MUST follow the global format `[NAME|type=TYPE[,KEY=VALUE]]`. Simple `NAME` is actually a shortcut notation for `type=registry,ref=NAME`.
 
-Compose Builder implementations MAY support custom types, the compose specification defineds canonical types which MUST be supported:
+Compose Builder implementations MAY support custom types, the Compose Specification defines canonical types which MUST be supported:
 
 - `registry` to retrieve build cache from an OCI image set by key `ref`
 
@@ -191,6 +191,8 @@ build:
 
 Cache target is defined using the same `type=TYPE[,KEY=VALUE]` syntax defined by [`cache_from`](#cache_from). 
 
+Unsupported cache target MUST be ignored and not prevent user for building image.
+
 ### extra_hosts
 
 `extra_hosts` adds hostname mappings at build-time. Use the same syntax as [extra_hosts](spec.md#extra_hosts).