push: start warning upcoming default change for push.default

In preparation for flipping the default to the "simple" mode from
the "matching" mode that is the historical default, start warning
users when they rely on unconfigured "git push" to default to the
"matching" mode.

Also, advertise for 'simple' where 'current' and 'upstream' are advised.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Simplify print_tool_help()

Eliminate a global variable and File::Find usage by building upon
basename() and glob() instead.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Eliminate global variables

Organize the script so that it has a single main() function which
calls out to dir_diff() and file_diff() functions. This eliminates
"dir-diff"-specific variables that do not need to be calculated when
performing a regular file-diff.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Move option values into a hash

Shorten the "my" declaration for all of the option-specific variables
by wrapping all of them in a hash.  This also gives us a place to
specify default values, should we need them.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Call the temp directory "git-difftool"

The "diffall" name was left over from when this functionality was part of
the "git-diffall" script in contrib/.  Make the naming consistent.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Use symlinks when diffing against the worktree

Teach difftool's --dir-diff mode to use symlinks to represent
files from the working copy, and make it the default behavior
for the non-Windows platforms.

Using symlinks is simpler and safer since we do not need to
worry about copying files back into the worktree.
The old behavior is still available as --no-symlinks.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Handle finding mergetools/ in a path with spaces

Use the original File::Find implementation from bf73fc2 (difftool:
print list of valid tools with '--tool-help', 2012-03-29) so that we
properly handle mergetools/ being located in a path containing
spaces.

One small difference is that we avoid using a global variable by
passing a reference to the list of tools.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Check all return codes from compare()

Handle the case where compare() is unable to read its inputs.
Emit a warning so that the user knows that something went wrong.

We may later want to restructure the code so that we can inhibit
tempdir cleanup when this condition is reached.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Wrap long lines for readability

Keep everything within 80 columns.  Wrap the user-facing messages too.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Handle compare() returning -1

Keep the temporary directory around when compare()
cannot read its input files, which is indicated by -1.

Defer tempdir creation to allow an early exit in setup_dir_diff().
Wrap the rest of the entry points in an exit_cleanup() function
to handle removing temporary files and error reporting.

Print the temporary files' location so that the user can
recover them.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
difftool: Disable --symlinks on cygwin

Symlinks are not ubiquitous on Windows so make --no-symlinks the default.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
test: rename $satisfied to $satisfied_prereq

All other shell variables that are used to globally keep track of
states related to prerequisite have "prereq" somewhere in their
names.  Be consistent and avoid potential name crashes with other
kinds of satisfaction in the future.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
test: allow prerequisite to be evaluated lazily

The test prerequisite mechanism is a useful way to allow some tests
in a test script to be skipped in environments that do not support
certain features (e.g. it is pointless to attempt checking how well
symbolic links are handled by Git on filesystems that do not support
them).  It is OK for commonly used prerequisites to be always tested
during start-up of a test script by having a codeblock that tests a
feature and calls test_set_prereq, but for an uncommon feature,
forcing 90% of scripts to pay the same probing overhead for
prerequisite they do not care about is wasteful.

Introduce a mechanism to probe the prerequiste lazily.  Changes are:

 - test_lazy_prereq () function, which takes the name of the
   prerequisite it probes and the script to probe for it, is
   added.  This only registers the name of the prerequiste that can
   be lazily probed and the script to eval (without running).

 - test_have_prereq() function (which is used by test_expect_success
   and also can be called directly by test scripts) learns to look
   at the list of prerequisites that can be lazily probed, and the
   prerequisites that have already been probed that way.  When asked
   for a prerequiste that can be but haven't been probed, the script
   registered with an earlier call to test_lazy_prereq is evaluated
   and the prerequisite is set.

 - test_run_lazy_prereq_() function is a helper to run the probe
   script with the same kind of sandbox as regular tests, helped by
   Jeff King.

Update the codeblock to probe and set SYMLINKS prerequisite using
the new mechanism as an example.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-lib: provide case insensitivity as a prerequisite

Case insensitivity plays a role in several tests and is tested in several
tests. Therefore, move the test from t003 into the test lib and use the
prerequisite in t0003.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t0050: use the CASE_INSENSITIVE_FS test prereq

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t0050: use the SYMLINKS test prereq

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
test-lib: provide UTF8 behaviour as a prerequisite

UTF8 behaviour of the filesystem (conversion from nfd to nfc)  plays a
role in several tests and is tested in several tests. Therefore, move
the test from t0050 into the test lib and use the prerequisite in t0050.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
remove unnecessary parameter from get_patch_ids()

get_patch_ids() takes an already initialized rev_info and a
prefix. The prefix is used when initalizing a second rev_info. Since
the initialized rev_info already has a prefix and the prefix never
changes, we can use the prefix from the initialized rev_info to
initialize the second rev_info.

Signed-off-by: Martin von Zweigbergk <martin.von.zweigbergk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff: do not use null sha1 as a sentinel value

The diff code represents paths using the diff_filespec
struct. This struct has a sha1 to represent the sha1 of the
content at that path, as well as a sha1_valid member which
indicates whether its sha1 field is actually useful. If
sha1_valid is not true, then the filespec represents a
working tree file (e.g., for the no-index case, or for when
the index is not up-to-date).

The diff_filespec is only used internally, though. At the
interfaces to the diff subsystem, callers feed the sha1
directly, and we create a diff_filespec from it. It's at
that point that we look at the sha1 and decide whether it is
valid or not; callers may pass the null sha1 as a sentinel
value to indicate that it is not.

We should not typically see the null sha1 coming from any
other source (e.g., in the index itself, or from a tree).
However, a corrupt tree might have a null sha1, which would
cause "diff --patch" to accidentally diff the working tree
version of a file instead of treating it as a blob.

This patch extends the edges of the diff interface to accept
a "sha1_valid" flag whenever we accept a sha1, and to use
that flag when creating a filespec. In some cases, this
means passing the flag through several layers, making the
code change larger than would be desirable.

One alternative would be to simply die() upon seeing
corrupted trees with null sha1s. However, this fix more
directly addresses the problem (while bogus sha1s in a tree
are probably a bad thing, it is really the sentinel
confusion sending us down the wrong code path that is what
makes it devastating). And it means that git is more capable
of examining and debugging these corrupted trees. For
example, you can still "diff --raw" such a tree to find out
when the bogus entry was introduced; you just cannot do a
"--patch" diff (just as you could not with any other
corrupted tree, as we do not have any content to diff).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
do not write null sha1s to on-disk index

We should never need to write the null sha1 into an index
entry (short of the 1 in 2^160 chance that somebody actually
has content that hashes to it). If we attempt to do so, it
is much more likely that it is a bug, since we use the null
sha1 as a sentinel value to mean "not valid".

The presence of null sha1s in the index (which can come
from, among other things, "update-index --cacheinfo", or by
reading a corrupted tree) can cause problems for later
readers, because they cannot distinguish the literal null
sha1 from its use a sentinel value.  For example, "git
diff-files" on such an entry would make it appear as if it
is stat-dirty, and until recently, the diff code assumed
such an entry meant that we should be diffing a working tree
file rather than a blob.

Ideally, we would stop such entries from entering even our
in-core index. However, we do sometimes legitimately add
entries with null sha1s in order to represent these sentinel
situations; simply forbidding them in add_index_entry breaks
a lot of the existing code. However, we can at least make
sure that our in-core sentinel representation never makes it
to disk.

To be thorough, we will test an attempt to add both a blob
and a submodule entry. In the former case, we might run into
problems anyway because we will be missing the blob object.
But in the latter case, we do not enforce connectivity
across gitlink entries, making this our only point of
enforcement. The current implementation does not care which
type of entry we are seeing, but testing both cases helps
future-proof the test suite in case that changes.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>