Merge branch 'jk/write-packed-refs-via-stdio'

Optimize the code path to write out the packed-refs file, which
especially matters in a repository with a large number of refs.

* jk/write-packed-refs-via-stdio:
  refs: write packed_refs file using stdio
Merge branch 'jk/faster-name-conflicts'

Optimize the check to see if a ref $F can be created by making sure
no existing ref has $F/ as its prefix, which especially matters in
a repository with a large number of existing refs.

* jk/faster-name-conflicts:
  refs: speed up is_refname_available
Merge branch 'js/fsck-tag-validation'

Teach "git fsck" to inspect the contents of annotated tag objects.

* js/fsck-tag-validation:
  Make sure that index-pack --strict checks tag objects
  Add regression tests for stricter tag fsck'ing
  fsck: check tag objects' headers
  Make sure fsck_commit_buffer() does not run out of the buffer
  fsck_object(): allow passing object data separately from the object itself
  Refactor type_from_string() to allow continuing after detecting an error
Merge branch 'jc/hash-object'

"hash-object" learned a new "--literally" option to hash any random
garbage into a loose object, to allow us to create a test data for
mechanisms to catch corrupt objects.

* jc/hash-object:
  hash-object: add --literally option
  hash-object: pass 'write_object' as a flag
  hash-object: reduce file-scope statics
Merge branch 'jc/hash-object-fsck-tag'

Using "hash-object --literally", test one of the new breakages
js/fsck-tag-validation topic teaches "fsck" to catch is caught.

* jc/hash-object-fsck-tag:
  t1450: make sure fsck detects a malformed tagger line
Merge branch 'jk/prune-packed-server-info'

Code cleanup.

* jk/prune-packed-server-info:
  repack: call prune_packed_objects() and update_server_info() directly
  server-info: clean up after writing info/packs
  make update-server-info more robust
  prune-packed: fix minor memory leak
Merge branch 'jc/ignore-sigpipe-while-running-hooks'

pre- and post-receive hooks are no longer required to read all
their inputs.

* jc/ignore-sigpipe-while-running-hooks:
  receive-pack: allow hooks to ignore its standard input stream
Merge branch 'jk/close-stderr-of-credential-cache-deamon'

Plug fd leaks.

* jk/close-stderr-of-credential-cache-deamon:
  credential-cache: close stderr in daemon process
Merge branch 'rs/realloc-array'

Code cleanup.

* rs/realloc-array:
  use REALLOC_ARRAY for changing the allocation size of arrays
  add macro REALLOC_ARRAY
Merge branch 'jk/branch-verbose-merged'

The "--verbose" option no longer breaks "git branch --merged $it".

* jk/branch-verbose-merged:
  branch: clean up commit flags after merge-filter walk
Merge branch 'sb/help-unknown-command-sort-fix'

Code cleanup.

* sb/help-unknown-command-sort-fix:
  help: fix the size passed to qsort
Update draft release notes to 2.2

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'master' into next

* master:
  Update draft release notes to 2.2