If you have these three gitattributes file:
(in $GIT_DIR/info/attributes)
a* foo !bar -baz
(in .gitattributes)
abc foo bar baz
(in t/.gitattributes)
ab* merge=filfre
abc -foo -bar
*.c frotz
the attributes given to path t/abc are computed as follows:
1. By examining t/.gitattributes (which is in the same directory
as the path in question), Git finds that the first line
matches. merge attribute is set. It also finds that the
second line matches, and attributes foo and bar are unset.
2. Then it examines .gitattributes (which is in the parent
directory), and finds that the first line matches, but
t/.gitattributes file already decided how merge, foo and bar
attributes should be given to this path, so it leaves foo and
bar unset. Attribute baz is set.
3. Finally it examines $GIT_DIR/info/attributes. This file is
used to override the in-tree settings. The first line is a
match, and foo is set, bar is reverted to unspecified state,
and baz is unset.
As the result, the attributes assignment to t/abc becomes:
foo set to true
bar unspecified
baz set to false
merge set to string value "filfre"
frotz unspecified
