While it makes sense to allow merging unrelated histories of two
projects that started independently into one, in the way "gitk" was
merged to "git" itself aka "the coolest merge ever", such a merge is
still an unusual event. Worse, if somebody creates an independent
history by starting from a tarball of an established project and
sends a pull request to the original project, "git merge" however
happily creates such a merge without any sign of something unusual
is happening.
Teach "git merge" to refuse to create such a merge by default,
unless the user passes a new "--allow-unrelated-histories" option to
tell it that the user is aware that two unrelated projects are
merged.
Because such a "two project merge" is a rare event, a configuration
option to always allow such a merge is not added.
We could add the same option to "git pull" and have it passed
through to underlying "git merge". I do not have a fundamental
opposition against such a feature, but this commit does not do so
and instead leaves it as low-hanging fruit for others, because such
a "two project merge" would be done after fetching the other project
into some location in the working tree of an existing project and
making sure how well they fit together, it is sufficient to allow a
local merge without such an option pass-through from "git pull" to
"git merge". Many tests that are updated by this patch does the
pass-through manually by turning:
git pull something
into its equivalent:
git fetch something &&
git merge --allow-unrelated-histories FETCH_HEAD
If somebody is inclined to add such an option, updated tests in this
change need to be adjusted back to:
git pull --allow-unrelated-histories something
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase [-i] --root $tip" can now be used to rewrite all the
history down to the root.
* cw/rebase-i-root:
t3404: make test 57 work with dash and others
Add tests for rebase -i --root without --onto
rebase -i: support --root without --onto
Test for likely breakages in t3404, including successful reordering of
non-conflicting changes with a new root, correct preservation of commit
message and author in a root commit when it is squashed with the
sentinel, and presence of the sentinel following a conflicting
cherry-pick of a new root.
Remove test_must_fail for git rebase --root without --onto from t3412 as
this case will now be successfully handled by an implicit git rebase -i.
Signed-off-by: Chris Webb <chris@arachsys.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just like
git rebase --onto newbase upstream branch error
displays the usage message, so should clearly
git rebase --onto newbase --root branch error
, but it doesn't. Instead, it ignores both "branch" and "error" and
rebases the current HEAD. This is because we try to match the number
of remainging arguments "$#", which fails to match "1" argument and
matches the "*" that really should have been a "0".
Make sure we display usage information when too many arguments are
given. Also fail-fast in case of similar bugs in the future by
matching on exactly 0 arguments and failing on unknown numbers.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Breaks in a test assertion's && chain can potentially hide
failures from earlier commands in the chain.
Commands intended to fail should be marked with !, test_must_fail, or
test_might_fail. The examples in this patch do not require that.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2182896 (t3412: clean up GIT_EDITOR usage, 2009-01-30) tried to clean up
the script's use of GIT_EDITOR, but it can further be simplified, because
that is how test-lib.sh sets things up already.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace all 'git log --graph' calls for history verification with the
combination of 'git log ...| git name-rev' first introduced by a6c7a27
(rebase -i: correctly remember --root flag across --continue,
2009-01-26). This should be less susceptible to format changes than
the --graph code.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
a6c7a27 (rebase -i: correctly remember --root flag across --continue,
2009-01-26) introduced a more portable GIT_EDITOR usage, but left the
old tests unchanged.
Since we never use the editor (all tests run the rebase script as
proposed by rebase -i), just disable it outright, which simplifies the
tests.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use the newly introduced test_commit() and test_merge() helpers.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some shells have issues with a single-shot environment variable export
when invoking a shell function. This fixes the ones I found that invoke
test_must_fail that way.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
d911d14 (rebase -i: learn to rebase root commit, 2009-01-02) tried to
remember the --root flag across a merge conflict in a broken way.
Introduce a flag file $DOTEST/rebase-root to fix and clarify.
While at it, also make sure $UPSTREAM is always initialized to guard
against existing values in the environment.
[tr: added tests]
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach git-rebase -i a new option --root, which instructs it to rebase
the entire history leading up to <branch>. This is mainly for
symmetry with ordinary git-rebase; it cannot be used to edit the root
commit in-place (it requires --onto <newbase>). Commits that already
exist in <newbase> are skipped.
In the normal mode of operation, this is fairly straightforward. We
run cherry-pick in a loop, and cherry-pick has supported picking the
root commit since f95ebf7 (Allow cherry-picking root commits,
2008-07-04).
In --preserve-merges mode, we track the mapping from old to rewritten
commits and use it to update the parent list of each commit. In this
case, we define 'rebase -i -p --root --onto $onto $branch' to rewrite
the parent list of all root commit(s) on $branch to contain $onto
instead.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach git-rebase a new option --root, which instructs it to rebase the
entire history leading up to <branch>. This option must be used with
--onto <newbase>, and causes commits that already exist in <newbase>
to be skipped. (Normal operation skips commits that already exist in
<upstream> instead.)
One possible use-case is with git-svn: suppose you start hacking
(perhaps offline) on a new project, but later notice you want to
commit this work to SVN. You will have to rebase the entire history,
including the root commit, on a (possibly empty) commit coming from
git-svn, to establish a history connection. This previously had to
be done by cherry-picking the root commit manually.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano
Chris Webb
Martin von Zweigbergk
Jonathan Nieder
Thomas Rast
Johannes Schindelin