Merge branch 'bc/hash-transition-interop-part-1'

SHA-256 transition.

* bc/hash-transition-interop-part-1:
  hex: print objects using the hash algorithm member
  hex: default to the_hash_algo on zero algorithm value
  builtin/pack-objects: avoid using struct object_id for pack hash
  commit-graph: don't store file hashes as struct object_id
  builtin/show-index: set the algorithm for object IDs
  hash: provide per-algorithm null OIDs
  hash: set, copy, and use algo field in struct object_id
  builtin/pack-redundant: avoid casting buffers to struct object_id
  Use the final_oid_fn to finalize hashing of object IDs
  hash: add a function to finalize object IDs
  http-push: set algorithm when reading object ID
  Always use oidread to read into struct object_id
  hash: add an algo member to struct object_id

diff --cc branch.c
Simple merge

diff --cc builtin/checkout.c
Simple merge

diff --cc builtin/grep.c
Simple merge

diff --cc builtin/ls-files.c
Simple merge

diff --cc builtin/pack-objects.c
Simple merge

diff --cc builtin/rebase.c
Simple merge

diff --cc dir.c
Simple merge

diff --cc http-push.c
Simple merge

diff --cc merge-ort.c
Simple merge

diff --cc merge-recursive.c
Simple merge

diff --cc read-cache.c
Simple merge

diff --cc refs.c
Simple merge

diff --cc refs/debug.c
index 001e30651c2c3d5313601c53ca3a783ce78d2c28,2665f943095c93171cc3bf7db80e6e345a9ba681..7db4abccc341b03a3c198633ab7f516bc43c08df
--- 1/refs/debug.c
--- 2/refs/debug.c
+++ b/refs/debug.c
@@@ -243,8 -243,7 +243,8 @@@ static int debug_read_raw_ref(struct re
        struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
        int res = 0;
  
-       oidcpy(oid, &null_oid);
+       oidcpy(oid, null_oid());
 +      errno = 0;
        res = drefs->refs->be->read_raw_ref(drefs->refs, refname, oid, referent,
                                            type);
  

diff --cc sequencer.c
Simple merge

diff --cc submodule.c
Simple merge

diff --cc wt-status.c
Simple merge