Base export target chache key on the exported target

The cache key for an export target should contain as target name
that of the export target (and its effective configuration) rather
than the exported target. As we computed the repository part of
the cache key for the target included in the key, this was still a
correct cache key except in the case an explicit file reference was
exported (as here, the information that the file was to be taken
rather than the target of the same name got lost). We still fix
this issue by making the implementation match our design (rather
than by including the file-reference bit in the cache key), as the
original design gives the cleaner protocol for target-level caching
as a service.

1 files changed, 7 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f48f24fd..ba7b9a1d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,13 @@ A feature release on top of `1.2.0`, backwards compatible.
 
 ### Fixes
 
+- The cache key used for an export target is now based on the export
+  target itself rather than that of the exported target. The latter
+  could lead to spourious cache hits, but only in the case where
+  an explicit file reference was exported and an regular target
+  with the same name exists. Where the new cache keys overlap with
+  the old ones, they refer to the same configured targets; so no
+  special action is to be taken when updating.
 - Improved protability and update of the bundled dependencies.
 - Various minor improvements and typo fixes in the documentation.
 - Fixed a race condition in an internal cache of `just execute` used for keeping