The internal logic used in "git blame" has been libified to make it
easier to use by cgit.

* js/blame-lib: (29 commits)
  blame: move entry prepend to libgit
  blame: move scoreboard setup to libgit
  blame: move scoreboard-related methods to libgit
  blame: move fake-commit-related methods to libgit
  blame: move origin-related methods to libgit
  blame: move core structures to header
  blame: create entry prepend function
  blame: create scoreboard setup function
  blame: create scoreboard init function
  blame: rework methods that determine 'final' commit
  blame: wrap blame_sort and compare_blame_final
  blame: move progress updates to a scoreboard callback
  blame: make sanity_check use a callback in scoreboard
  blame: move no_whole_file_rename flag to scoreboard
  blame: move xdl_opts flags to scoreboard
  blame: move show_root flag to scoreboard
  blame: move reverse flag to scoreboard
  blame: move contents_from to scoreboard
  blame: move copy/move thresholds to scoreboard
  blame: move stat counters to scoreboard
  ...

Make the "indent" heuristics the default in "diff" and diff.indentHeuristics
configuration variable an escape hatch for those who do no want it.

* mb/diff-default-to-indent-heuristics:
  add--interactive: drop diff.indentHeuristic handling
  diff: enable indent heuristic by default
  diff: have the diff-* builtins configure diff before initializing revisions
  diff: make the indent heuristic part of diff's basic configuration

Conversion from uchar[20] to struct object_id continues.

* bc/object-id: (53 commits)
  object: convert parse_object* to take struct object_id
  tree: convert parse_tree_indirect to struct object_id
  sequencer: convert do_recursive_merge to struct object_id
  diff-lib: convert do_diff_cache to struct object_id
  builtin/ls-tree: convert to struct object_id
  merge: convert checkout_fast_forward to struct object_id
  sequencer: convert fast_forward_to to struct object_id
  builtin/ls-files: convert overlay_tree_on_cache to object_id
  builtin/read-tree: convert to struct object_id
  sha1_name: convert internals of peel_onion to object_id
  upload-pack: convert remaining parse_object callers to object_id
  revision: convert remaining parse_object callers to object_id
  revision: rename add_pending_sha1 to add_pending_oid
  http-push: convert process_ls_object and descendants to object_id
  refs/files-backend: convert many internals to struct object_id
  refs: convert struct ref_update to use struct object_id
  ref-filter: convert some static functions to struct object_id
  Convert struct ref_array_item to struct object_id
  Convert the verify_pack callback to struct object_id
  Convert lookup_tag to struct object_id
  ...

textconv_object is used in places other than blame.c and should be moved
to a more appropriate location.  Other textconv related functions are
located in diff.c so that seems as good a place as any.

Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The feature was included in v2.11 (released 2016-11-29) and we got no
negative feedback. Quite the opposite, all feedback we got was positive.

Turn it on by default. Users who dislike the feature can turn it off
by setting diff.indentHeuristic (which also configures plumbing commands,
see prior patches).

The change to t/t4051-diff-function-context.sh is needed because the
heuristic shifts the changed hunk in the patch.  To get the same result
regardless of the heuristic configuration, we modify the test file
differently:  We insert a completely new line after line 2, instead of
simply duplicating it.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

This heuristic was originally introduced as an experimental feature,
and therefore part of the UI configuration.

But the user often sees diffs generated by plumbing commands like
diff-tree.  Moving the indent heuristic into diff's basic configuration
prepares the way for diff plumbing commands to respect the setting.

The heuristic itself merely makes the diffs more aesthetically
pleasing, without changing their correctness.  Scripts that rely on
the diff plumbing commands should not care whether or not the heuristic
is employed.

Signed-off-by: Marc Branchaud <marcnarc@xiplink.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Convert as many instances of unsigned char [20] as possible.  Update the
callers of notes_cache_get and notes_cache_put to use the new interface.
Among the functions updated are callers of
lookup_commit_reference_gently, which we will soon convert.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: René Genz <liebundartig@freenet.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Conversion from unsigned char [40] to struct object_id continues.

* bc/object-id:
  Documentation: update and rename api-sha1-array.txt
  Rename sha1_array to oid_array
  Convert sha1_array_for_each_unique and for_each_abbrev to object_id
  Convert sha1_array_lookup to take struct object_id
  Convert remaining callers of sha1_array_lookup to object_id
  Make sha1_array_append take a struct object_id *
  sha1-array: convert internal storage for struct sha1_array to object_id
  builtin/pull: convert to struct object_id
  submodule: convert check_for_new_submodule_commits to object_id
  sha1_name: convert disambiguate_hint_fn to take object_id
  sha1_name: convert struct disambiguate_state to object_id
  test-sha1-array: convert most code to struct object_id
  parse-options-cb: convert sha1_array_append caller to struct object_id
  fsck: convert init_skiplist to struct object_id
  builtin/receive-pack: convert portions to struct object_id
  builtin/pull: convert portions to struct object_id
  builtin/diff: convert to struct object_id
  Convert GIT_SHA1_RAWSZ used for allocation to GIT_MAX_RAWSZ
  Convert GIT_SHA1_HEXSZ used for allocation to GIT_MAX_HEXSZ
  Define new hash-size constants for allocating memory

To generate a patch id, we format the diff header into a
fixed-size buffer, and then feed the result to our sha1
computation. The fixed buffer has size '4*PATH_MAX + 20',
which in theory accommodates the four filenames plus some
extra data. Except:

  1. The filenames may not be constrained to PATH_MAX. The
     static value may not be a real limit on the current
     filesystem. Moreover, we may compute patch-ids for
     names stored only in git, without touching the current
     filesystem at all.

  2. The 20 bytes is not nearly enough to cover the
     extra content we put in the buffer.

As a result, the data we feed to the sha1 computation may be
truncated, and it's possible that a commit with a very long
filename could erroneously collide in the patch-id space
with another commit. For instance, if one commit modified
"really-long-filename/foo" and another modified "bar" in the
same directory.

In practice this is unlikely. Because the filenames are
repeated, and because there's a single cutoff at the end of
the buffer, the offending filename would have to be on the
order of four times larger than PATH_MAX.

We could fix this by moving to a strbuf. However, we can
observe that the purpose of formatting this in the first
place is to feed it to git_SHA1_Update(). So instead, let's
just feed each part of the formatted string directly. This
actually ends up more readable, and we can even factor out
some duplicated bits from the various conditional branches.

Technically this may change the output of patch-id for very
long filenames, but it's not worth making an exception for
this in the --stable output. It was a bug, and one that only
affected an unlikely set of paths.  And anyway, the exact
value would have varied from platform to platform depending
on the value of PATH_MAX, so there is no "stable" value.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>