Merge branch 'jk/diff-compact-heuristic'

It turns out that the earlier effort to update the heuristics may
want to use a bit more time to mature.  Turn it off by default.

* jk/diff-compact-heuristic:
  diff: disable compaction heuristic for now

Documentation/diff-config.txt

@@ -170,6 +170,11 @@ diff.tool::
 
 include::mergetools-diff.txt[]
 
+diff.compactionHeuristic::
+	Set this option to `true` to enable an experimental heuristic that
+	shifts the hunk boundary in an attempt to make the resulting
+	patch easier to read.
+
 diff.algorithm::
 	Choose a diff algorithm.  The variants are as follows:
 +

Documentation/diff-options.txt

@@ -63,6 +63,13 @@ ifndef::git-format-patch[]
 	Synonym for `-p --raw`.
 endif::git-format-patch[]
 
+--compaction-heuristic::
+--no-compaction-heuristic::
+	These are to help debugging and tuning an experimental
+	heuristic (which is off by default) that shifts the hunk
+	boundary in an attempt to make the resulting patch easier
+	to read.
+
 --minimal::
 	Spend extra time to make sure the smallest possible
 	diff is produced.

diff.c

@@ -26,7 +26,7 @@
 #endif
 
 static int diff_detect_rename_default;
-static int diff_compaction_heuristic = 1;
+static int diff_compaction_heuristic; /* experimental */
 static int diff_rename_limit_default = 400;
 static int diff_suppress_blank_empty;
 static int diff_use_color_default = -1;