Merge branch 'br/blame-ignore' into pu

"git blame" learned to "ignore" commits in the history, whose
effects (as well as their presence) get ignored.

* br/blame-ignore:
  blame: use a fingerprint heuristic to match ignored lines
  blame: optionally track line fingerprints during fill_blame_origin()
  blame: add config options to handle output for ignored lines
  blame: add the ability to ignore commits and their changes
  blame: use a helper function in blame_chunk()
  Move init_skiplist() outside of fsck

Author: gitster

Documentation/blame-options.txt

@@ -110,5 +110,23 @@ commit. And the default value is 40. If there are more than one
 `-C` options given, the <num> argument of the last `-C` will
 take effect.
 
+--ignore-rev <rev>::
+	Ignore changes made by the revision when assigning blame, as if the
+	change never happened.  Lines that were changed or added by an ignored
+	commit will be blamed on the previous commit that changed that line or
+	nearby lines.  This option may be specified multiple times to ignore
+	more than one revision.  If the `blame.markIgnoredLines` config option
+	is set, then lines that were changed by an ignored commit will be
+	marked with a `*` in the blame output.  If the
+	`blame.maskIgnoredUnblamables` config option is set, then those lines that
+	we could not attribute to another revision are outputted as all zeros.
+
+--ignore-revs-file <file>::
+	Ignore revisions listed in `file`, one unabbreviated object name per line.
+	Whitespace and comments beginning with `#` are ignored.  This option may be
+	repeated, and these files will be processed after any files specified with
+	the `blame.ignoreRevsFile` config option.  An empty file name, `""`, will
+	clear the list of revs from previously processed files.
+
 -h::
 	Show help message.

Documentation/config/blame.txt

@@ -19,3 +19,19 @@ blame.showEmail::
 blame.showRoot::
 	Do not treat root commits as boundaries in linkgit:git-blame[1].
 	This option defaults to false.
+
+blame.ignoreRevsFile::
+	Ignore revisions listed in the file, one unabbreviated object name per
+	line, in linkgit:git-blame[1].  Whitespace and comments beginning with
+	`#` are ignored.  This option may be repeated multiple times.  Empty
+	file names will reset the list of ignored revisions.  This option will
+	be handled before the command line option `--ignore-revs-file`.
+
+blame.maskIgnoredUnblamables::
+	Output an object hash of all zeros for lines that were changed by an ignored
+	revision and that we could not attribute to another revision in the output
+	of linkgit:git-blame[1].
+
+blame.markIgnoredLines::
+	Mark lines that were changed by an ignored revision with a '*' in the
+	output of linkgit:git-blame[1].

Documentation/git-blame.txt

@@ -10,6 +10,7 @@ SYNOPSIS
 [verse]
 'git blame' [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-e] [-p] [-w] [--incremental]
 	    [-L <range>] [-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>]
+	    [--ignore-rev <rev>] [--ignore-revs-file <file>]
 	    [--progress] [--abbrev=<n>] [<rev> | --contents <file> | --reverse <rev>..<rev>]
 	    [--] <file>