About a week ago, I started experimenting to add a new functionality to the 
diff machinery: We want to color moved lines differently! This will aid 
to review patches such as the patch "Move libified code from builtin/apply.c to 
Or a smaller example:

    git show 11979b9

In the original patch series I just used the xdl diff machinery multiple times
to obtain the output for a multi pass algorithm I need for this coloring.
This was one of Junios main concerns (We have to rely on the xdl stuff to 
yield the same output in the two passes).

This brings in another approach:
 * run the xdl stuff only once
 * In case we do not ask for coloring moves, put it out immediately
   (small detour: we do not use fprintf/fputs directly but we channel
   all output through the emit_line_* interface)
 * When asking for coloring moves: buffer all its output for now.
   Feed the line by line into the move detection algorithm.
 * then output it all at once using the information from the move detection
   to recolor moves while outputting.
While viewing the output of 11979b9 again, I notice a small bug in the proposal,
but I'd rather be asking for review of the whole design approach.

Stefan Beller (17):
  diff: move line ending check into emit_hunk_header
  diff: emit_{add, del, context}_line to increase {pre,post}image line
  diff.c: drop tautologous condition in emit_line_0
  diff.c: factor out diff_flush_patch_all_file_pairs
  diff.c: emit_line_0 can handle no color setting
  diff.c: convert fn_out_consume to use emit_line_*
  diff.c: convert builtin_diff to use emit_line_*
  diff.c: convert emit_rewrite_diff to use emit_line_*
  diff.c: convert emit_rewrite_lines to use emit_line_*
  submodule.c: convert show_submodule_summary to use emit_line_fmt
  diff.c: convert emit_binary_diff_body to use emit_line_*
  diff.c: convert show_stats to use emit_line_*
  diff.c: convert word diffing to use emit_line_*
  diff.c: convert diff_flush to use emit_line_*
  diff.c: convert diff_summary to use emit_line_*
  diff: buffer output in emit_line_0
  diff.c: color moved lines differently

 Documentation/config.txt               |  12 +-
 Documentation/diff-options.txt         |   7 +
 contrib/completion/git-completion.bash |   2 +
 diff.c                                 | 666 +++++++++++++++++++++++----------
 diff.h                                 |  35 +-
 submodule.c                            |  42 +--
 submodule.h                            |   3 +-
 t/t4015-diff-whitespace.sh             | 229 ++++++++++++
 8 files changed, 760 insertions(+), 236 deletions(-)


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