Re: A case where diff.colorMoved=plain is more sensible than diff.colorMoved=zebra & others

> Let's ignore how bad this patch is for git.git, and just focus on how
> diff.colorMoved treats it:
> 
>      diff --git a/builtin/add.c b/builtin/add.c
>      index f65c172299..d1155322ef 100644
>      --- a/builtin/add.c
>      +++ b/builtin/add.c
>      @@ -6,5 +6,3 @@
>       #include "cache.h"
>      -#include "config.h"
>       #include "builtin.h"
>      -#include "lockfile.h"
>       #include "dir.h"
>      diff --git a/builtin/am.c b/builtin/am.c
>      index 8f27f3375b..eded15aa8a 100644
>      --- a/builtin/am.c
>      +++ b/builtin/am.c
>      @@ -6,3 +6,2 @@
>       #include "cache.h"
>      -#include "config.h"
>       #include "builtin.h"
>      diff --git a/builtin/blame.c b/builtin/blame.c
>      index 06a7163ffe..44a754f190 100644
>      --- a/builtin/blame.c
>      +++ b/builtin/blame.c
>      @@ -8,3 +8,2 @@
>       #include "cache.h"
>      -#include "config.h"
>       #include "color.h"
>      diff --git a/cache.h b/cache.h
>      index ca36b44ee0..ea8d60b94a 100644
>      --- a/cache.h
>      +++ b/cache.h
>      @@ -4,2 +4,4 @@
>       #include "git-compat-util.h"
>      +#include "config.h"
>      +#include "new.h"
>       #include "strbuf.h"
> 
> This is a common thing that's useful to have highlighted, e.g. we move
> includes of config.h to some common file, so I want to se all the
> deleted config.h lines as moved into the cache.h line, and then the
> "lockfile.h" I removed while I was at it plain remove, and the new
> "new.h" plain added.
> 
> Exactly that is what you get with diff.colorMoved=plain, but the default
> of diff.colorMoved=zebra gets confused by this and highlights no moves
> at all, same or "blocks" and "dimmed-zebra".
> 
> So at first I thought this had something to do with the many->one
> detection, but it seems to be simpler, we just don't detect a move of
> 1-line with anything but plain, e.g. this works as expected in all modes
> and detects the many->one:
> 
>      diff --git a/builtin/add.c b/builtin/add.c
>      index f65c172299..f4fda75890 100644
>      --- a/builtin/add.c
>      +++ b/builtin/add.c
>      @@ -5,4 +5,2 @@
>        */
>      -#include "cache.h"
>      -#include "config.h"
>       #include "builtin.h"
>      diff --git a/builtin/branch.c b/builtin/branch.c
>      index 0c55f7f065..52e39924d3 100644
>      --- a/builtin/branch.c
>      +++ b/builtin/branch.c
>      @@ -7,4 +7,2 @@
> 
>      -#include "cache.h"
>      -#include "config.h"
>       #include "color.h"
>      diff --git a/cache.h b/cache.h
>      index ca36b44ee0..d4146dbf8a 100644
>      --- a/cache.h
>      +++ b/cache.h
>      @@ -3,2 +3,4 @@
> 
>      +#include "cache.h"
>      +#include "config.h"
>       #include "git-compat-util.h"
> 
> So is there some "must be at least two consecutive lines" condition for
> not-plain, or is something else going on here?