Merge branch 'ds/commit-graph-lockfile-fix'

Update to ds/generation-numbers topic.

* ds/commit-graph-lockfile-fix:
  commit-graph: fix UX issue when .lock file exists
  commit-graph.txt: update design document
  merge: check config before loading commits
  commit: use generation number in remove_redundant()
  commit: add short-circuit to paint_down_to_common()
  commit: use generation numbers for in_merge_bases()
  ref-filter: use generation number for --contains
  commit-graph: always load commit-graph information
  commit: use generations in paint_down_to_common()
  commit-graph: compute generation numbers
  commit: add generation number to struct commit
  ref-filter: fix outdated comment on in_commit_list

diff --cc builtin/merge.c
Simple merge

diff --cc commit-graph.c
Simple merge

diff --cc commit.c
Simple merge

diff --cc commit.h
index e48f05dffcac2fc780386626701cdc64bd795076,b5afde1ae901d3b90643d8e84a3fbfe997f2ba65..cb943013d06a58f2e0427a33f5ab718df23e730f
--- 1/commit.h
--- 2/commit.h
+++ b/commit.h
@@@ -33,7 -33,7 +36,8 @@@ struct commit 
         */
        struct tree *maybe_tree;
        uint32_t graph_pos;
+       uint32_t generation;
 +      unsigned int index;
  };
  
  extern int save_commit_buffer;

diff --cc object.c
Simple merge

diff --cc ref-filter.c
Simple merge

diff --cc sha1-file.c
Simple merge