Merge branch 'jc/sha1-name-more'

Teaches the object name parser things like a "git describe" output
is always a commit object, "A" in "git log A" must be a committish,
and "A" and "B" in "git log A...B" both must be committish, etc., to
prolong the lifetime of abbreviated object names.

* jc/sha1-name-more: (27 commits)
  t1512: match the "other" object names
  t1512: ignore whitespaces in wc -l output
  rev-parse --disambiguate=<prefix>
  rev-parse: A and B in "rev-parse A..B" refer to committish
  reset: the command takes committish
  commit-tree: the command wants a tree and commits
  apply: --build-fake-ancestor expects blobs
  sha1_name.c: add support for disambiguating other types
  revision.c: the "log" family, except for "show", takes committish
  revision.c: allow handle_revision_arg() to take other flags
  sha1_name.c: introduce get_sha1_committish()
  sha1_name.c: teach lookup context to get_sha1_with_context()
  sha1_name.c: many short names can only be committish
  sha1_name.c: get_sha1_1() takes lookup flags
  sha1_name.c: get_describe_name() by definition groks only commits
  sha1_name.c: teach get_short_sha1() a commit-only option
  sha1_name.c: allow get_short_sha1() to take other flags
  get_sha1(): fix error status regression
  sha1_name.c: restructure disambiguation of short names
  sha1_name.c: correct misnamed "canonical" and "res"
  ...

commit.c

@@ -68,7 +68,7 @@ struct commit *lookup_commit_reference_by_name(const char *name)
 	unsigned char sha1[20];
 	struct commit *commit;
 
-	if (get_sha1(name, sha1))
+	if (get_sha1_committish(name, sha1))
 		return NULL;
 	commit = lookup_commit_reference(sha1);
 	if (!commit || parse_commit(commit))