Re: [BUG] Documentation: git log: --exit-code undocumented?

Junio C Hamano [off-list ref] writes:

David Kastrup [off-list ref] writes:

quoted

I disagree that --exit-code does nothing: it indicates whether the
listed log is empty.  So for example

git log -1 --exit-code a..b > /dev/null

can be used to figure out whether "a" is a proper ancestor of "b" or
not.

Hmph.

    $ git log --exit-code master..maint >/dev/null; echo $?
    0
    $ git log --exit-code maint..master >/dev/null; echo $?
    1

That is a strange way to use --exit-code.  I suspect that if you did
this, you will get 0 from the log between HEAD~..HEAD

    $ git checkout master^0
    $ git commit --allow-empty -m empty
    $ git log --exit-code HEAD~..HEAD

even though HEAD~ is a proper ancestor of HEAD, so it is not giving
us anything useful.  Isn't it a mere artifact that "log" happens to
share the underlying machinery with "diff" that --exit-code shows a
non-zero exit when there is any single commit in the range that has
any change?

Possibly: I haven't checked the underlying code for the details.  At any
rate, it is an option git log accepts for whatever reason.

-- 
David Kastrup