First: in Documentation/diffcore.txt there is an example of broken pair
diffcore-break: For Splitting Up "Complete Rewrites"
----------------------------------------------------
The second transformation in the chain is diffcore-break, and is
controlled by the -B option to the git-diff-* commands. This is
used to detect a filepair that represents "complete rewrite" and
break such filepair into two filepairs that represent delete and
create. E.g. If the input contained this filepair:
------------------------------------------------
:100644 100644 bcd1234... 0123456... M file0
------------------------------------------------
and if it detects that the file "file0" is completely rewritten,
it changes it to:
------------------------------------------------
:100644 000000 bcd1234... 0000000... D file0
:000000 100644 0000000... 0123456... A file0
------------------------------------------------
Shouldn't the last block read for the modern git read:
------------------------------------------------
:100644 000000 bcd1234... 0123456... M99 file0
------------------------------------------------
or is it only for '-B' togehter with '-M' or '-C'?
Second: do you have per chance good examples of broken (and perhaps
merged together) pair, such that it is affected by --diff-filter=B;
with -B<num> or -B<num1>/<num2> parameters needed, if required. COPYING
and Makefile are one good example, but do you have literal files with
similar behavior?
Third: Do "git diff --no-index" (filesystem diff) can show breaking /
use dissimilarity? I couldn't make it work...