annotate COPYING @ 48195:4d5a13253d34

dirstate-v2: Replace the 32-bit `mode` field with two bits

Previously we stored the entire value from `stat_result.st_mode`,
like dirstate-v1 does. However only the executable permission
and type of file (only symbolic links and normal files are supported)
are relevant to Mecurial.

So replace this field with two bits in the existing bitfield byte.
For now the unused space is left as padding, as it will be used
for something else soon.

Differential Revision: https://phab.mercurial-scm.org/D11635

                    GNU GENERAL PUBLIC LICENSE
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