Re: [PATCH v2 0/9] diff --color-moved-ws fixes and enhancment

> From: Phillip Wood <phillip.wood@dunelm.org.uk>
> 
> Thanks to Stefan for his feedback on v1. I've updated patches 2 & 8 in
> response to those comments - see the range-diff below for details (the
> patch numbers are off by one in the range diff, I think because the
> first patch is unchanged and so it was used as the merge base by
> --range-diff=<old-head>. For some reason the range-diff also includes
> the notes even though I did not give --notes to format-patch)
> 
> When trying out the new --color-moved-ws=allow-indentation-change I
> was disappointed to discover it did not work if the indentation
> contains a mix of spaces and tabs. This series reworks it so that it
> does.
> 
> 
> Phillip Wood (9):
>    diff: document --no-color-moved
>    Use "whitespace" consistently
>    diff: allow --no-color-moved-ws
>    diff --color-moved-ws: demonstrate false positives
>    diff --color-moved-ws: fix false positives
>    diff --color-moved=zebra: be stricter with color alternation
>    diff --color-moved-ws: optimize allow-indentation-change
>    diff --color-moved-ws: modify allow-indentation-change
>    diff --color-moved-ws: handle blank lines
> 
>   Documentation/diff-options.txt |  15 ++-
>   Documentation/git-cat-file.txt |   8 +-
>   diff.c                         | 219 +++++++++++++++++++++------------
>   t/t4015-diff-whitespace.sh     |  99 ++++++++++++++-
>   4 files changed, 255 insertions(+), 86 deletions(-)
> 
> Range-diff against v1:
> 1:  ae58ae4f29 ! 1:  4939ee371d diff: use whitespace consistently
>      @@ -1,9 +1,10 @@
>       Author: Phillip Wood <phillip.wood@dunelm.org.uk>
>       
>      -    diff: use whitespace consistently
>      +    Use "whitespace" consistently
>       
>      -    Most of the documentation uses 'whitespace' rather than 'white space'
>      -    or 'white spaces' convert to latter two to the former for consistency.
>      +    Most of the messages and documentation use 'whitespace' rather than
>      +    'white space' or 'white spaces' convert to latter two to the former for
>      +    consistency.
>       
>           Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>       
>      @@ -29,6 +30,39 @@
>        	whitespace is the same per line. This is incompatible with the
>        	other modes.
>       
>      + diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
>      + --- a/Documentation/git-cat-file.txt
>      + +++ b/Documentation/git-cat-file.txt
>      +@@
>      + stdin, and the SHA-1, type, and size of each object is printed on stdout. The
>      + output format can be overridden using the optional `<format>` argument. If
>      + either `--textconv` or `--filters` was specified, the input is expected to
>      +-list the object names followed by the path name, separated by a single white
>      +-space, so that the appropriate drivers can be determined.
>      ++list the object names followed by the path name, separated by a single
>      ++whitespace, so that the appropriate drivers can be determined.
>      +
>      + OPTIONS
>      + -------
>      +@@
>      + 	Print object information and contents for each object provided
>      + 	on stdin.  May not be combined with any other options or arguments
>      + 	except `--textconv` or `--filters`, in which case the input lines
>      +-	also need to specify the path, separated by white space.  See the
>      ++	also need to specify the path, separated by whitespace.  See the
>      + 	section `BATCH OUTPUT` below for details.
>      +
>      + --batch-check::
>      + --batch-check=<format>::
>      + 	Print object information for each object provided on stdin.  May
>      + 	not be combined with any other options or arguments except
>      + 	`--textconv` or `--filters`, in which case the input lines also
>      +-	need to specify the path, separated by white space.  See the
>      ++	need to specify the path, separated by whitespace.  See the
>      + 	section `BATCH OUTPUT` below for details.
>      +
>      + --batch-all-objects::
>      +
>        diff --git a/diff.c b/diff.c
>        --- a/diff.c
>        +++ b/diff.c
> 2:  7072bc6211 = 2:  204c7fea9d diff: allow --no-color-moved-ws
> 3:  ce3ad19eea = 3:  542b79b215 diff --color-moved-ws: demonstrate false positives
> 4:  700e0b61e7 = 4:  4ffb5c4122 diff --color-moved-ws: fix false positives
> 5:  9ecd8159a7 = 5:  a3a84f90c5 diff --color-moved=zebra: be stricter with color alternation
> 6:  1b1158b1ca = 6:  f94f2e0bae diff --color-moved-ws: optimize allow-indentation-change
> 7:  d8a362be6a ! 7:  fe8eb9cdbc diff --color-moved-ws: modify allow-indentation-change
>      @@ -17,7 +17,7 @@
>       
>           This commit changes the way the indentation is handled to track the
>           visual size of the indentation rather than the characters in the
>      -    indentation. This has they benefit that any whitespace errors do not
>      +    indentation. This has the benefit that any whitespace errors do not
>           interfer with the move detection (the whitespace errors will still be
>           highlighted according to --ws-error-highlight). During the discussion
>           of this feature there were concerns about the correct detection of
>      @@ -30,7 +30,7 @@
>               they are uncolored.
>       
>           Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>      -    Changes since rfc:
>      +    changes since rfc:
>            - It now replaces the existing implementation rather than adding a new
>              mode.
>            - The indentation deltas are now calculated once for each line and
>      @@ -49,8 +49,8 @@
>        	const char *line;
>        	int len;
>        	int flags;
>      -+	int indent_off;
>      -+	int indent_width;
>      ++	int indent_off;   /* Offset to first non-whitespace character */
>      ++	int indent_width; /* The visual width of the indentation */
>        	enum diff_symbol s;
>        };
>        #define EMITTED_DIFF_SYMBOL_INIT {NULL}
> 8:  1f7e99d45c = 8:  e600f8247c diff --color-moved-ws: handle blank lines
>      
>