Re: [PATCH] t4202 (log): add failing test for log with subtree

Thomas Rast wrote:

I think you've misunderstood the whole thing. The histories of M^1 and M^2 are completely unrelated: they're from different projects altogether. Considering the /ichi in M^2 a "rename" of the /ichi in M^1 is completely wrong. They have nothing to do with each other. I intentionally named it "ichi" in my orphan branch just to drive my point. I suspect you've got confused because I used an orphan branch to emulate a different project's history. If you want an end-user understanding of the problem, use git subtree:

    $ cd /tmp
    $ git clone gh:artagnon/varlog
    $ cd varlog
    $ git subtree add --prefix=clayoven \
       gh:artagnon/clayoven master
    $ cd clayoven
    $ git log README.md

What do you expect? The same output you would get if you cloned gh:artagnon/clayoven separately and executed 'git log README.md' on it.

Now, clayoven's README.md (the one in HEAD^2) has nothing to do with varlog's README.md (the one in HEAD^1). It's just incidental that both projects have a README.md. I repeat: clayoven and varlog have _nothing_ to do with each other. If I say git log --follow README.md in the above example, I don't even get the HEAD commit. And I wouldn't expect to either.

I will repeat this: --follow has nothing to do with the problem I've specified. And it is not tied to "renaming" (ie. changing the name/path of a file) as you've made it look. If you're still not convinced, I've included a testcase for --follow "following" over a merge commit (include it after the --follow test in the t4202). Try it without the --follow and you'll see what I mean. Neither the filename nor the filepath of ichi has changed in this example.

-- 8< --
test_expect_success '--follow over merge' '
	git checkout -b featurebranch
	echo foodle >>ichi &&
	git add ichi &&
	test_tick &&
	git commit -m "add a line to the end of ichi" &&
	echo moodle >unrelated &&
	git add unrelated &&
	test_tick &&
	git commit -m quux &&
	git checkout master &&
	mv ichi ichi.bak &&
	echo gooble >ichi &&
	cat ichi.bak >>ichi &&
	git add ichi &&
	test_tick &&
	git commit -m "add a line to the beginning of ichi" &&
	git merge featurebranch &&
	git log --follow --oneline ichi >actual &&
	cat >expect <<-\EOF &&
	df26551 add a line to the beginning of ichi
	882d8d9 add a line to the end of ichi
	2fbe8c0 third
	f7dab8e second
	3a2fdcb initial
	EOF
	test_cmp expect actual
'