fetch: add --unshallow for turning shallow repo into complete one

The user can do --depth=2147483647 (*) for restoring complete repo
now. But it's hard to remember. Any other numbers larger than the
longest commit chain in the repository would also do, but some
guessing may be involved. Make easy-to-remember --unshallow an alias
for --depth=2147483647.

Make upload-pack recognize this special number as infinite depth. The
effect is essentially the same as before, except that upload-pack is
more efficient because it does not have to traverse to the bottom
anymore.

The chance of a user actually wanting exactly 2147483647 commits
depth, not infinite, on a repository with a history that long, is
probably too small to consider. The client can learn to add or
subtract one commit to avoid the special treatment when that actually
happens.

(*) This is the largest positive number a 32-bit signed integer can
    contain. JGit and older C Git store depth as "int" so both are OK
    with this number. Dulwich does not support shallow clone.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
upload-pack: fix off-by-one depth calculation in shallow clone

get_shallow_commits() is used to determine the cut points at a given
depth (i.e. the number of commits in a chain that the user likes to
get). However we count current depth up to the commit "commit" but we
do the cutting at its parents (i.e. current depth + 1). This makes
upload-pack always return one commit more than requested. This patch
fixes it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fetch: elaborate --depth action

--depth is explained as deepen, but the way it's applied, it can
shorten the history as well. Keen users may have noticed the
implication by the phrase "the specified number of commits from the
tip of each remote branch". Put "shorten" in the description to make
it clearer.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
clone: do not export and unexport GIT_CONFIG

Earlier, dc87183 (use GIT_CONFIG only in "git config", not other
programs, 2008-06-30) made sure that the environment variable is
never used outside "git config", but "git clone", after creating a
directory for the new repository and until the init_db() function
populates its .git/ directory, exported the variable for no good
reason.  No hook will run from init_db() and more importantly no
hook can run until init_db() finishes creation of the new
repository, so it cannot be used by any invocation of "git config"
by definition.

Stop doing the useless export/unexport.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-cvsimport.txt: cvsps-2 is deprecated

git-cvsimport relies on version 2 of cvsps and does not work with the
new version 3.  Since cvsps 3.x does not currently work as well as
version 2 for incremental import, document this fact.

Specifically, there is no way to make new git-cvsimport that supports
cvsps 3.x and have a seamless transition for existing users since cvsps
3.x needs a time from which to continue importing and git-cvsimport does
not save the time of the last import or import into a specific namespace
so there is no safe way to calculate the time of the last import.

Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t7102 (reset): don't hardcode SHA-1 in expected outputs

Take the expected SHA-1 digest in a variable, and use it instead of
hardcoding when checking the result.

Signed-off-by: Alexey Shumkin <Alex.Crezoff@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t9902: protect test from stray build artifacts

When you have random build artifacts in your build directory, left
behind by running "make" while on another branch, the "git help -a"
command run by __git_list_all_commands in the completion script that
is being tested does not have a way to know that they are not part
of the subcommands this build will ship.  Such extra subcommands may
come from the user's $PATH.  They will interfere with the tests that
expect a certain prefix to uniquely expand to a known completion.

Instrument the completion script and give it a way for us to tell
what (subset of) subcommands we are going to ship.

Also add a test to "git --help <prefix><TAB>" expansion.  It needs
to show not just commands but some selected documentation pages.

Based on an idea by Jeff King.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
ident: do not drop username when reading from /etc/mailname

An earlier conversion from fgets() to strbuf_getline() in the
codepath to read from /etc/mailname to learn the default host-part
of the ident e-mail address forgot that strbuf_getline() stores the
line at the beginning of the buffer just like fgets().

The "username@" the caller has prepared in the strbuf, expecting the
function to append the host-part to it, was lost because of this.

Reported-by: Mihai Rusu <dizzy@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-p4.py: support Python 2.5

Python 2.5 and older do not accept None as the first argument to
translate() and complain with:

   TypeError: expected a character buffer object

As suggested by Pete Wyckoff, let's just replace the call to translate()
with a regex search which should be more clear and more portable.

This allows git-p4 to be used with Python 2.5.

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-p4.py: support Python 2.4

Python 2.4 lacks the following features:

   subprocess.check_call
   struct.pack_into

Take a cue from 460d1026 and provide an implementation of the
CalledProcessError exception.  Then replace the calls to
subproccess.check_call with calls to subprocess.call that check the return
status and raise a CalledProcessError exception if necessary.

The struct.pack_into in t/9802 can be converted into a single struct.pack
call which is available in Python 2.4.

Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Acked-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fetch: run gc --auto after fetching

We generally try to run "gc --auto" after any commands that
might introduce a large number of new objects. An obvious
place to do so is after running "fetch", which may introduce
new loose objects or packs (depending on the size of the
fetch).

While an active developer repository will probably
eventually trigger a "gc --auto" on another action (e.g.,
git-rebase), there are two good reasons why it is nicer to
do it at fetch time:

  1. Read-only repositories which track an upstream (e.g., a
     continuous integration server which fetches and builds,
     but never makes new commits) will accrue loose objects
     and small packs, but never coalesce them into a more
     efficient larger pack.

  2. Fetching is often already perceived to be slow to the
     user, since they have to wait on the network. It's much
     more pleasant to include a potentially slow auto-gc as
     part of the already-long network fetch than in the
     middle of productive work with git-rebase or similar.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fetch-pack: avoid repeatedly re-scanning pack directory

When we look up a sha1 object for reading via parse_object() =>
read_sha1_file() => read_object() callpath, we first check
packfiles, and then loose objects. If we still haven't found it, we
re-scan the list of packfiles in `objects/pack`. This final step
ensures that we can co-exist with a simultaneous repack process
which creates a new pack and then prunes the old object.

This extra re-scan usually does not have a performance impact for
two reasons:

  1. If an object is missing, then typically the re-scan will find a
     new pack, then no more misses will occur.  Or if it truly is
     missing, then our next step is usually to die().

  2. Re-scanning is cheap enough that we do not even notice.

However, these do not always hold. The assumption in (1) is that the
caller is expecting to find the object. This is usually the case,
but the call to `parse_object` in `everything_local` does not follow
this pattern. It is looking to see whether we have objects that the
remote side is advertising, not something we expect to
have. Therefore if we are fetching from a remote which has many refs
pointing to objects we do not have, we may end up re-scanning the
pack directory many times.

Even with this extra re-scanning, the impact is often not noticeable
due to (2); we just readdir() the packs directory and skip any packs
that are already loaded. However, if there are a large number of
packs, even enumerating the directory can be expensive, especially
if we do it repeatedly.

Having this many packs is a good sign the user should run `git gc`,
but it would still be nice to avoid having to scan the directory at
all.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'jk/maint-gc-auto-after-fetch' into jk/gc-auto-after-fetch

* jk/maint-gc-auto-after-fetch:
  fetch-pack: avoid repeatedly re-scanning pack directory
  fetch: run gc --auto after fetching
branch: no detached HEAD check when editing another branch's description

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
INSTALL: git-p4 does not support Python 3

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'nd/fetch-depth-is-broken'

"git fetch --depth" was broken in at least three ways.  The
resulting history was deeper than specified by one commit, it was
unclear how to wipe the shallowness of the repository with the
command, and documentation was misleading.

* nd/fetch-depth-is-broken:
  fetch: elaborate --depth action
  upload-pack: fix off-by-one depth calculation in shallow clone
  fetch: add --unshallow for turning shallow repo into complete one
Merge branch 'jc/no-git-config-in-clone'

We stopped paying attention to $GIT_CONFIG environment that points
at a single configuration file from any command other than "git config"
quite a while ago, but "git clone" internally set, exported, and
then unexported the variable during its operation unnecessarily.

* jc/no-git-config-in-clone:
  clone: do not export and unexport GIT_CONFIG
Merge branch 'as/test-cleanup'

* as/test-cleanup:
  t7102 (reset): don't hardcode SHA-1 in expected outputs
Merge branch 'jc/do-not-let-random-file-interfere-with-completion-tests'

Scripts to test bash completion was inherently flaky as it was
affected by whatever random things the user may have on $PATH.

* jc/do-not-let-random-file-interfere-with-completion-tests:
  t9902: protect test from stray build artifacts
Merge branch 'jk/cvsimport-does-not-work-with-cvsps3'

Warn people that other tools are more recommendable over
cvsimport+cvsps2 combo when doing a one-shot import, and cvsimport
will not work with cvsps3.

* jk/cvsimport-does-not-work-with-cvsps3:
  git-cvsimport.txt: cvsps-2 is deprecated