branch: mark missing tracking branch as gone

If a branch has been set to track a upstream, but the upstream branch
is missing, the tracking info is silently ignored in the output of
some commands such as "git branch -vv" and "git status", as if there
were no such tracking settings.

Junio suggested missing upstream should be reported [1], such as:

    $ git branch -v -v
      master    e67ac84 initial
    * topic     3fc0f2a [topicbase: gone] topic

    $ git status
    # On branch topic
    # Your branch is based on 'topicbase', but the upstream is gone.
    #   (use "git branch --unset-upstream" to fixup)
    ...

    $ git status -b -s
    ## topic...topicbase [gone]
    ...

In order to do like that, we need to distinguish these three cases
(i.e. no tracking, with configured but no longer valid tracking, and
with tracking) in function stat_tracking_info(). So the refactored
function stat_tracking_info() has three return values: -1 (with "gone"
base), 0 (no base), and 1 (with base).

[1]: http://thread.gmane.org/gmane.comp.version-control.git/231830/focus=232288

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
status: always show tracking branch even no change

In order to see what the current branch is tracking, one way is using
"git branch -v -v", but branches other than the current are also
reported. Another way is using "git status", such as:

    $ git status
    # On branch master
    # Your branch is ahead of 'origin/master' by 1 commit.
    ...

But this will not work if there is no change between the current
branch and its upstream. Always report upstream tracking info
even if there is no difference, so that "git status" is consistent
for checking tracking info for current branch. E.g.

    $ git status
    # On branch feature1
    # Your branch is identical to 'github/feature1'.
    ...

    $ git status -bs
    ## feature1...github/feature1
    ...

    $ git checkout feature1
    Already on 'feature1'
    Your branch is identical to 'github/feature1'.
    ...

Also add some test cases in t6040.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
create_delta_index: simplify condition always evaluating to true

The code sequence  ' (1u << i) < hsize && i < 31 ' is a multi step
process, whose first step requires that 'i' is already less that 31,
otherwise the result (1u << i)  is undefined (and  'undef_val < hsize'
can therefore be assumed to be 'false'), and so the later test  i < 31
can always be optimized away as dead code ('i' is already less than 31,
or the short circuit 'and' applies).

So we need to get rid of that code. One way would be to exchange the
order of the conditions, so the expression 'i < 31 && (1u << i) < hsize'
would remove that optimized unstable code already.

However when checking the previous lines in that function, we can deduce
that 'hsize' must always be smaller than (1u<<31), since 506049c7df2c6
(fix >4GiB source delta assertion failure), because 'entries' is
capped at an upper bound of 0xfffffffeU, so 'hsize' contains a maximum
value of 0x3fffffff, which is smaller than (1u<<31), so the value of
'i' will never be larger than 31 and we can remove that condition
entirely.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Acked-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
move setup_alternate_shallow and write_shallow_commits to shallow.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
shallow: only add shallow graft points to new shallow file

for_each_commit_graft() goes through all graft points and shallow
boudaries are just one special kind of grafting. If $GIT_DIR/shallow
and $GIT_DIR/info/grafts are both present, write_shallow_commits may
catch both sets, accidentally turning some graft points to shallow
boundaries. Don't do that.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
shallow: add setup_temporary_shallow()

This function is like setup_alternate_shallow() except that it does
not lock $GIT_DIR/shallow. It's supposed to be used when a program
generates temporary shallow for for use by another program, then throw
the shallow file away.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
upload-pack: delegate rev walking in shallow fetch to pack-objects

upload-pack has a special rev walking code for shallow recipients. It
works almost like the similar code in pack-objects except:

1. in upload-pack, graft points could be added for deepening

2. also when the repository is deepened, the shallow point will be
   moved further away from the tip, but the old shallow point will be
   marked as edge to produce more efficient packs. See 6523078 (make
   shallow repository deepening more network efficient - 2009-09-03)

pass the file to pack-objects via --shallow-file. This will override
$GIT_DIR/shallow and give pack-objects the exact repository shape that
upload-pack has.

mark edge commits by revision command arguments. Even if old shallow
points are passed as "--not" revisions as in this patch, they will not
be picked up by mark_edges_uninteresting() because this function looks
up to parents for edges, while in this case the edge is the children,
in the opposite direction. This will be fixed in the next patch when
all given uninteresting commits are marked as edges.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
list-objects: reduce one argument in mark_edges_uninteresting

mark_edges_uninteresting() is always called with this form

  mark_edges_uninteresting(revs->commits, revs, ...);

Remove the first argument and let mark_edges_uninteresting figure that
out by itself. It helps answer the question "are this commit list and
revs related in any way?" when looking at mark_edges_uninteresting
implementation.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
list-objects: mark more commits as edges in mark_edges_uninteresting

The purpose of edge commits is to let pack-objects know what objects
it can use as base, but does not need to include in the thin pack
because the other side is supposed to already have them. So far we
mark uninteresting parents of interesting commits as edges. But even
an unrelated uninteresting commit (that the other side has) may become
a good base for pack-objects and help produce more efficient packs.

This is especially true for shallow clone, when the client issues a
fetch with a depth smaller or equal to the number of commits the
server is ahead of the client. For example, in this commit history the
client has up to "A" and the server has up to "B":

    -------A---B
     have--^   ^
              /
       want--+

If depth 1 is requested, the commit list to send to the client
includes only B. The way m_e_u is working, it checks if parent commits
of B are uninteresting, if so mark them as edges. Due to shallow
effect, commit B is grafted to have no parents and the revision walker
never sees A as the parent of B. In fact it marks no edges at all in
this simple case and sends everything B has to the client even if it
could have excluded what A and also the client already have. In a
slightly different case where A is not a direct parent of B (iow there
are commits in between A and B), marking A as an edge can still save
some because B may still have stuff from the far ancestor A.

There is another case from the previous patch, when we deepen a ref
from C->E to A->E:

    ---A---B   C---D---E
     want--^   ^       ^
       shallow-+      /
          have-------+

In this case we need to send A and B to the client, and C (i.e. the
current shallow point that the client informs the server) is a very
good base because it's closet to A and B. Normal m_e_u won't recognize
C as an edge because it only looks back to parents (i.e. A<-B) not the
opposite way B->C even if C is already marked as uninteresting commit
by the previous patch.

This patch includes all uninteresting commits from command line as
edges and lets pack-objects decide what's best to do. The upside is we
have better chance of producing better packs in certain cases. The
downside is we may need to process some extra objects on the server
side.

For the shallow case on git.git, when the client is 5 commits behind
and does "fetch --depth=3", the result pack is 99.26 KiB instead of
4.92 MiB.

Reported-and-analyzed-by: Matthijs Kooijman <matthijs@stdin.nl>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rebase -i: fix cases ignoring core.commentchar

180bad3d (rebase -i: respect core.commentchar, 2013-02-11) updated
"rebase -i" to honor core.commentchar but missed one instance of
hard-coded '#' comment character in skip_unnecessary_picks().

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rebase -i: fix core.commentchar regression

9a46c25bdbf79744 (rebase: interactive: fix short SHA-1 collision,
2013-08-12) added transform_todo_ids() which assumes incorrectly that
the comment character is always '#', however, this has not been the case
since 180bad3d10fe3a7f (rebase -i: respect core.commentchar, 2013-02-11)
patched rebase -i to respect core.commentchar. Fix this regression.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
bash prompt: test the prompt with newline in repository path

Newlines in the path to a git repository were not an issue for the
git-specific bash prompt before commit efaa0c1532 (bash prompt:
combine 'git rev-parse' executions in the main code path, 2013-06-17),
because the path returned by 'git rev-parse --git-dir' was directly
stored in a variable, and this variable was later always accessed
inside double quotes.

Newlines are not an issue after commit efaa0c1532 either, but it's
more subtle.  Since efaa0c1532 we use the following single 'git
rev-parse' execution to query various info about the repository:

  git rev-parse --git-dir --is-inside-git-dir \
          --is-bare-repository --is-inside-work-tree

The results to these queries are separated by a newline character in
the output, e.g.:

  /home/szeder/src/git/.git
  false
  false
  true

A newline in the path to the git repository could potentially break
the parsing of these results and ultimately the bash prompt, unless
the parsing is done right.  Commit efaa0c1532 got it right, as I
consciously started parsing 'git rev-parse's output from the end,
where each record is a single line containing either 'true' or 'false'
or, after e3e0b9378b (bash prompt: combine 'git rev-parse' for
detached head, 2013-06-24), the abbreviated commit object name, and
all what remains at the beginning is the path to the git repository,
no matter how many lines it is.

This subtlety really warrants its own test, especially since I didn't
explain it in the log message or in an in-code comment back then, so
add a test to excercise the prompt with newline characters in the path
to the repository.  Guard this test with the FUNNYNAMES prerequisite,
because not all filesystems support newlines in filenames.  Note that
'git rev-parse --git-dir' prints '.git' or '.' when at the top of the
worktree or the repository, respectively, and only prints the full
path to the repository when in a subdirectory, hence the need for
changing into a subdir in the test.

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jx/branch-vv-always-compare-with-upstream' into pu

* jx/branch-vv-always-compare-with-upstream:
  status: always show tracking branch even no change
  branch: mark missing tracking branch as gone
  branch: not report invalid tracking branch
Merge branch 'es/rebase-i-no-abbrev' into pu

* es/rebase-i-no-abbrev:
  rebase -i: fix core.commentchar regression
Merge branch 'es/rebase-i-respect-core-commentchar' into pu

* es/rebase-i-respect-core-commentchar:
  rebase -i: fix cases ignoring core.commentchar
Merge branch 'nd/fetch-into-shallow' into pu

* nd/fetch-into-shallow:
  list-objects: mark more commits as edges in mark_edges_uninteresting
  list-objects: reduce one argument in mark_edges_uninteresting
  upload-pack: delegate rev walking in shallow fetch to pack-objects
  shallow: add setup_temporary_shallow()
  shallow: only add shallow graft points to new shallow file
  move setup_alternate_shallow and write_shallow_commits to shallow.c
Merge branch 'sb/diff-delta-remove-needless-comparison' into pu

* sb/diff-delta-remove-needless-comparison:
  create_delta_index: simplify condition always evaluating to true
Merge branch 'sg/bash-prompt-lf-in-cwd-test' into pu

* sg/bash-prompt-lf-in-cwd-test:
  bash prompt: test the prompt with newline in repository path