Commit Graph

12399 Commits

Author SHA1 Message Date
Junio C Hamano
53cae9e0f8 Merge branch 'wc/find-commit-with-pattern-on-detached-head'
"git rev-parse ':/substring'" did not consider the history leading
only to HEAD when looking for a commit with the given substring,
when the HEAD is detached.  This has been fixed.

* wc/find-commit-with-pattern-on-detached-head:
  sha1-name.c: for ":/", find detached HEAD commits
2018-07-24 14:50:49 -07:00
Junio C Hamano
8fa8a4f1ec Merge branch 'jt/partial-clone-fsck-connectivity'
Partial clone support of "git clone" has been updated to correctly
validate the objects it receives from the other side.  The server
side has been corrected to send objects that are directly
requested, even if they may match the filtering criteria (e.g. when
doing a "lazy blob" partial clone).

* jt/partial-clone-fsck-connectivity:
  clone: check connectivity even if clone is partial
  upload-pack: send refs' objects despite "filter"
2018-07-24 14:50:47 -07:00
Junio C Hamano
7633ff48ed Merge branch 'bc/send-email-auto-cte'
The content-transfer-encoding of the message "git send-email" sends
out by default was 8bit, which can cause trouble when there is an
overlong line to bust RFC 5322/2822 limit.  A new option 'auto' to
automatically switch to quoted-printable when there is such a line
in the payload has been introduced and is made the default.

* bc/send-email-auto-cte:
  docs: correct RFC specifying email line length
  send-email: automatically determine transfer-encoding
  send-email: accept long lines with suitable transfer encoding
  send-email: add an auto option for transfer encoding
2018-07-24 14:50:47 -07:00
Junio C Hamano
88df0fa659 Merge branch 'jt/connectivity-check-after-unshallow'
"git fetch" failed to correctly validate the set of objects it
received when making a shallow history deeper, which has been
corrected.

* jt/connectivity-check-after-unshallow:
  fetch-pack: write shallow, then check connectivity
  fetch-pack: implement ref-in-want
  fetch-pack: put shallow info in output parameter
  fetch: refactor to make function args narrower
  fetch: refactor fetch_refs into two functions
  fetch: refactor the population of peer ref OIDs
  upload-pack: test negotiation with changing repository
  upload-pack: implement ref-in-want
  test-pkt-line: add unpack-sideband subcommand
2018-07-24 14:50:44 -07:00
Junio C Hamano
0ce5a698c6 Merge branch 'en/rebase-consistency'
"git rebase" behaved slightly differently depending on which one of
the three backends gets used; this has been documented and an
effort to make them more uniform has begun.

* en/rebase-consistency:
  git-rebase: make --allow-empty-message the default
  t3401: add directory rename testcases for rebase and am
  git-rebase.txt: document behavioral differences between modes
  directory-rename-detection.txt: technical docs on abilities and limitations
  git-rebase.txt: address confusion between --no-ff vs --force-rebase
  git-rebase: error out when incompatible options passed
  t3422: new testcases for checking when incompatible options passed
  git-rebase.sh: update help messages a bit
  git-rebase.txt: document incompatible options
2018-07-24 14:50:43 -07:00
Brandon Williams
f351b0aba4 pack-protocol: mention and point to docs for protocol v2
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-24 12:59:51 -07:00
Eric Sunshine
ee6cbf712e format-patch: allow --interdiff to apply to a lone-patch
When submitting a revised version of a patch or series, it can be
helpful (to reviewers) to include a summary of changes since the
previous attempt in the form of an interdiff, typically in the cover
letter. However, it is occasionally useful, despite making for a noisy
read, to insert an interdiff into the commentary section of the lone
patch of a 1-patch series.

Therefore, extend "git format-patch --interdiff=<prev>" to insert an
interdiff into the commentary section of a lone patch rather than
requiring a cover letter. The interdiff is indented to avoid confusing
git-am and human readers into considering it part of the patch proper.

Implementation note: Generating an interdiff for insertion into the
commentary section of a patch which itself is currently being generated
requires invoking the diffing machinery recursively. However, the
machinery does not (presently) support this since it uses global state.
Consequently, we need to take care to stash away the state of the
in-progress operation while generating the interdiff, and restore it
after.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-23 12:50:06 -07:00
Eric Sunshine
126facf821 format-patch: add --interdiff option to embed diff in cover letter
When submitting a revised version of a patch series, it can be helpful
(to reviewers) to include a summary of changes since the previous
attempt in the form of an interdiff, however, doing so involves manually
copy/pasting the diff into the cover letter.

Add an --interdiff option to automate this process. The argument to
--interdiff specifies the tip of the previous attempt against which to
generate the interdiff. For example:

    git format-patch --cover-letter --interdiff=v1 -3 v2

The previous attempt and the patch series being formatted must share a
common base.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-23 12:50:06 -07:00
Stefan Beller
1e83b9bfdd Documentation/git-interpret-trailers: explain possible values
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 15:23:59 -07:00
Derrick Stolee
c4d25228eb config: create core.multiPackIndex setting
The core.multiPackIndex config setting controls the multi-pack-
index (MIDX) feature. If false, the setting will disable all reads
from the multi-pack-index file.

Read this config setting in the new prepare_multi_pack_index_one()
which is called during prepare_packed_git(). This check is run once
per repository.

Add comparison commands in t5319-multi-pack-index.sh to check
typical Git behavior remains the same as the config setting is turned
on and off. This currently includes 'git rev-list' and 'git log'
commands to trigger several object database reads. Currently, these
would only catch an error in the prepare_multi_pack_index_one(), but
with later commits will catch errors in object lookups, abbreviations,
and approximate object counts.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee
662148c435 midx: write object offsets
The final pair of chunks for the multi-pack-index file stores the object
offsets. We default to using 32-bit offsets as in the pack-index version
1 format, but if there exists an offset larger than 32-bits, we use a
trick similar to the pack-index version 2 format by storing all offsets
at least 2^31 in a 64-bit table; we use the 32-bit table to point into
that 64-bit table as necessary.

We only store these 64-bit offsets if necessary, so create a test that
manipulates a version 2 pack-index to fake a large offset. This allows
us to test that the large offset table is created, but the data does not
match the actual packfile offsets. The multi-pack-index offset does match
the (corrupted) pack-index offset, so a future feature will compare these
offsets during a 'verify' step.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee
d7cacf29cc midx: write object id fanout chunk
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee
0d5b3a5ef7 midx: write object ids in a chunk
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee
32f3c541e3 multi-pack-index: write pack names in chunk
The multi-pack-index needs to track which packfiles it indexes. Store
these in our first required chunk. Since filenames are not well
structured, add padding to keep good alignment in later chunks.

Modify the 'git multi-pack-index read' subcommand to output the
existence of the pack-file name chunk. Modify t5319-multi-pack-index.sh
to reflect this new output and the new expected number of chunks.

Defense in depth: A pattern we are using in the multi-pack-index feature
is to verify the data as we write it. We want to ensure we never write
invalid data to the multi-pack-index. There are many checks that verify
that the values we are writing fit the format definitions. This mainly
helps developers while working on the feature, but it can also identify
issues that only appear when dealing with very large data sets. These
large sets are hard to encode into test cases.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee
a340773026 multi-pack-index: add 'write' verb
In anticipation of writing multi-pack-indexes, add a skeleton
'git multi-pack-index write' subcommand and send the options to a
write_midx_file() method. Also create a skeleton test script that
tests the 'write' subcommand.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee
6a257f03ba multi-pack-index: add builtin
This new 'git multi-pack-index' builtin will be the plumbing access
for writing, reading, and checking multi-pack-index files. The
initial implementation is a no-op.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:26 -07:00
Stefan Beller
626c0b5d39 diff.c: offer config option to control ws handling in move detection
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-19 12:02:54 -07:00
Stefan Beller
ca1f4ae4df diff.c: add white space mode to move detection that allows indent changes
The option of --color-moved has proven to be useful as observed on the
mailing list. However when refactoring sometimes the indentation changes,
for example when partitioning a functions into smaller helper functions
the code usually mostly moved around except for a decrease in indentation.

To just review the moved code ignoring the change in indentation, a mode
to ignore spaces in the move detection as implemented in a previous patch
would be enough.  However the whole move coloring as motivated in commit
2e2d5ac (diff.c: color moved lines differently, 2017-06-30), brought
up the notion of the reviewer being able to trust the move of a "block".

As there are languages such as python, which depend on proper relative
indentation for the control flow of the program, ignoring any white space
change in a block would not uphold the promises of 2e2d5ac that allows
reviewers to pay less attention to the inside of a block, as inside
the reviewer wants to assume the same program flow.

This new mode of white space ignorance will take this into account and will
only allow the same white space changes per line in each block. This patch
even allows only for the same change at the beginning of the lines.

As this is a white space mode, it is made exclusive to other white space
modes in the move detection.

This patch brings some challenges, related to the detection of blocks.
We need a wide net to catch the possible moved lines, but then need to
narrow down to check if the blocks are still intact. Consider this
example (ignoring block sizes):

 - A
 - B
 - C
 +    A
 +    B
 +    C

At the beginning of a block when checking if there is a counterpart
for A, we have to ignore all space changes. However at the following
lines we have to check if the indent change stayed the same.

Checking if the indentation change did stay the same, is done by computing
the indentation change by the difference in line length, and then assume
the change is only in the beginning of the longer line, the common tail
is the same. That is why the test contains lines like:

 - <TAB> A
 ...
 + A <TAB>
 ...

As the first line starting a block is caught using a compare function that
ignores white spaces unlike the rest of the block, where the white space
delta is taken into account for the comparison, we also have to think about
the following situation:

 - A
 - B
 -   A
 -   B
 +    A
 +    B
 +      A
 +      B

When checking if the first A (both in the + and - lines) is a start of
a block, we have to check all 'A' and record all the white space deltas
such that we can find the example above to be just one block that is
indented.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-19 12:02:54 -07:00
Jeff King
da4398d6a0 add core.usereplacerefs config option
We can already disable replace refs using a command line
option or environment variable, but those are awkward to
apply universally. Let's add a config option to do the same
thing.

That raises the question of why one might want to do so
universally. The answer is that replace refs violate the
immutability of objects. For instance, if you wanted to
cache the diff between commit XYZ and its parent, then in
theory that never changes; the hash XYZ represents the total
state. But replace refs violate that; pushing up a new ref
may create a completely new diff.

The obvious "if it hurts, don't do it" answer is not to
create replace refs if you're doing this kind of caching.
But for a site hosting arbitrary repositories, they may want
to allow users to share replace refs with each other, but
not actually respect them on the site (because the caching
is more important than the replace feature).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18 15:45:27 -07:00
Junio C Hamano
b7bd9486b0 Third batch for 2.19 cycle
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18 12:24:17 -07:00
Junio C Hamano
18f2717578 Merge branch 'ms/core-icase-doc'
Clarify that setting core.ignoreCase to deviate from reality would
not turn a case-incapable filesystem into a case-capable one.

* ms/core-icase-doc:
  Documentation: declare "core.ignoreCase" as internal variable
2018-07-18 12:20:35 -07:00
Junio C Hamano
06994ae065 Merge branch 'ds/commit-graph'
Docfix.

* ds/commit-graph:
  commit-graph: fix documentation inconsistencies
2018-07-18 12:20:34 -07:00
Junio C Hamano
3c5b6ee92e Merge branch 'tz/exclude-doc-smallfixes'
Doc updates.

* tz/exclude-doc-smallfixes:
  dir.c: fix typos in core.excludesfile comment
  gitignore.txt: clarify default core.excludesfile path
2018-07-18 12:20:34 -07:00
Junio C Hamano
2f826b060c Merge branch 'js/rebase-recreate-merge'
Docfix.

* js/rebase-recreate-merge:
  rebase: fix documentation formatting
2018-07-18 12:20:33 -07:00
Junio C Hamano
d18602f412 Merge branch 'jk/branch-l-0-deprecation'
The "-l" option in "git branch -l" is an unfortunate short-hand for
"--create-reflog", but many users, both old and new, somehow expect
it to be something else, perhaps "--list".  This step warns when "-l"
is used as a short-hand for "--create-reflog" and warns about the
future repurposing of the it when it is used.

* jk/branch-l-0-deprecation:
  branch: deprecate "-l" option
  t: switch "branch -l" to "branch --create-reflog"
  t3200: unset core.logallrefupdates when testing reflog creation
2018-07-18 12:20:31 -07:00
Junio C Hamano
d036d667b7 Merge branch 'tb/grep-column'
"git grep" learned the "--column" option that gives not just the
line number but the column number of the hit.

* tb/grep-column:
  contrib/git-jump/git-jump: jump to exact location
  grep.c: add configuration variables to show matched option
  builtin/grep.c: add '--column' option to 'git-grep(1)'
  grep.c: display column number of first match
  grep.[ch]: extend grep_opt to allow showing matched column
  grep.c: expose {,inverted} match column in match_line()
  Documentation/config.txt: camel-case lineNumber for consistency
2018-07-18 12:20:31 -07:00
Junio C Hamano
eb9056358c Merge branch 'vs/typofixes'
Doc fix.

* vs/typofixes:
  Documentation: spelling and grammar fixes
2018-07-18 12:20:31 -07:00
Junio C Hamano
5e6140e76f Merge branch 'bw/protocol-v2'
Doc fix.

* bw/protocol-v2:
  protocol-v2 doc: put HTTP headers after request
2018-07-18 12:20:30 -07:00
Junio C Hamano
a4d4427bc6 Merge branch 'bw/config-refer-to-gitsubmodules-doc'
Docfix.

* bw/config-refer-to-gitsubmodules-doc:
  docs: link to gitsubmodules
2018-07-18 12:20:30 -07:00
Andrei Rybak
dd61cc1c2e Documentation: fix --color option formatting
Add missing colon in two places to fix formatting of options.

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18 11:24:05 -07:00
Henning Schild
1e7adb9756 gpg-interface: introduce new signature format "x509" using gpgsm
This commit allows git to create and check x509 type signatures using
gpgsm.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18 10:02:23 -07:00
Henning Schild
b02f51b196 gpg-interface: introduce new config to select per gpg format program
Supporting multiple signing formats we will have the need to configure a
custom program each. Add a new config value to cater for that.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18 10:02:21 -07:00
Henning Schild
57a8dd75df gpg-interface: add new config to select how to sign a commit
Add "gpg.format" where the user can specify which type of signature to
use for commits. At the moment only "openpgp" is supported and the value is
not even used. This commit prepares for a new types of signatures.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-17 12:14:11 -07:00
Stefan Beller
b3095712f9 diff.c: decouple white space treatment from move detection algorithm
In the original implementation of the move detection logic the choice for
ignoring white space changes is the same for the move detection as it is
for the regular diff.  Some cases came up where different treatment would
have been nice.

Allow the user to specify that white space should be ignored differently
during detection of moved lines than during generation of added and removed
lines. This is done by providing analogs to the --ignore-space-at-eol,
-b, and -w options by introducing the option --color-moved-ws=<modes>
with the modes named "ignore-space-at-eol", "ignore-space-change" and
"ignore-all-space", which is used only during the move detection phase.

As we change the default, we'll adjust the tests.

For now we do not infer any options to treat white spaces in the move
detection from the generic white space options given to diff.
This can be tuned later to reasonable default.

As we plan on adding more white space related options in a later patch,
that interferes with the current white space options, use a flag field
and clamp it down to  XDF_WHITESPACE_FLAGS, as that (a) allows to easily
check at parse time if we give invalid combinations and (b) can reuse
parts of this patch.

By having the white space treatment in its own option, we'll also
make it easier for a later patch to have an config option for
spaces in the move detection.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-17 11:25:31 -07:00
Stefan Beller
51da15eb23 diff.c: add a blocks mode for moved code detection
The new "blocks" mode provides a middle ground between plain and zebra.
It is as intuitive (few colors) as plain, but still has the requirement
for a minimum of lines/characters to count a block as moved.

Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
 (https://public-inbox.org/git/87o9j0uljo.fsf@evledraar.gmail.com/)
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-17 11:25:31 -07:00
Jonathan Nieder
3029970275 gc: do not return error for prior errors in daemonized mode
Some build machines started consistently failing to fetch updated
source using "repo sync", with error

  error: The last gc run reported the following. Please correct the root cause
  and remove /build/.repo/projects/tools/git.git/gc.log.
  Automatic cleanup will not be performed until the file is removed.

  warning: There are too many unreachable loose objects; run 'git prune' to remove them.

The cause takes some time to describe.

In v2.0.0-rc0~145^2 (gc: config option for running --auto in
background, 2014-02-08), "git gc --auto" learned to run in the
background instead of blocking the invoking command.  In this mode, it
closed stderr to avoid interleaving output with any subsequent
commands, causing warnings like the above to be swallowed; v2.6.3~24^2
(gc: save log from daemonized gc --auto and print it next time,
2015-09-19) addressed that by storing any diagnostic output in
.git/gc.log and allowing the next "git gc --auto" run to print it.

To avoid wasteful repeated fruitless gcs, when gc.log is present, the
subsequent "gc --auto" would die after printing its contents.  Most
git commands, such as "git fetch", ignore the exit status from "git gc
--auto" so all is well at this point: the user gets to see the error
message, and the fetch succeeds, without a wasteful additional attempt
at an automatic gc.

External tools like repo[1], though, do care about the exit status
from "git gc --auto".  In non-daemonized mode, the exit status is
straightforward: if there is an error, it is nonzero, but after a
warning like the above, the status is zero.  The daemonized mode, as a
side effect of the other properties provided, offers a very strange
exit code convention:

 - if no housekeeping was required, the exit status is 0

 - the first real run, after forking into the background, returns exit
   status 0 unconditionally.  The parent process has no way to know
   whether gc will succeed.

 - if there is any diagnostic output in gc.log, subsequent runs return
   a nonzero exit status to indicate that gc was not triggered.

There's nothing for the calling program to act on on the basis of that
error.  Use status 0 consistently instead, to indicate that we decided
not to run a gc (just like if no housekeeping was required).  This
way, repo and similar tools can get the benefit of the same behavior
as tools like "git fetch" that ignore the exit status from gc --auto.

Once the period of time described by gc.pruneExpire elapses, the
unreachable loose objects will be removed by "git gc --auto"
automatically.

[1] https://gerrit-review.googlesource.com/c/git-repo/+/10598/

Reported-by: Andrii Dehtiarov <adehtiarov@google.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-17 11:24:36 -07:00
Jonathan Tan
42cc7485a2 negotiator/skipping: skip commits during fetch
Introduce a new negotiation algorithm used during fetch that skips
commits in an effort to find common ancestors faster. The skips grow
similarly to the Fibonacci sequence as the commit walk proceeds further
away from the tips. The skips may cause unnecessary commits to be
included in the packfile, but the negotiation step typically ends more
quickly.

Usage of this algorithm is guarded behind the configuration flag
fetch.negotiationAlgorithm.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-16 14:51:12 -07:00
Derrick Stolee
e0d1bcf825 multi-pack-index: add format details
The multi-pack-index feature generalizes the existing pack-index
feature by indexing objects across multiple pack-files.

Describe the basic file format, using a 12-byte header followed by
a lookup table for a list of "chunks" which will be described later.
The file ends with a footer containing a checksum using the hash
algorithm.

The header allows later versions to create breaking changes by
advancing the version number. We can also change the hash algorithm
using a different version value.

We will add the individual chunk format information as we introduce
the code that writes that information.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-12 13:55:02 -07:00
Derrick Stolee
ceab693d1f multi-pack-index: add design document
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-12 13:55:02 -07:00
William Chargin
6b3351e799 sha1-name.c: for ":/", find detached HEAD commits
This patch broadens the set of commits matched by ":/<pattern>" to
include commits reachable from HEAD but not any named ref. This avoids
surprising behavior when working with a detached HEAD and trying to
refer to a commit that was recently created and only exists within the
detached state.

If multiple worktrees exist, only the current worktree's HEAD is
considered reachable. This is consistent with the existing behavior for
other per-worktree refs: e.g., bisect refs are considered reachable, but
only within the relevant worktree.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: William Chargin <wchargin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-12 12:07:25 -07:00
Johannes Schindelin
caafecfcf1 rebase --rebase-merges: adjust man page for octopus support
Now that we support octopus merges in the `--rebase-merges` mode,
we should give users who actually read the manuals a chance to know
about this fact.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-11 14:52:33 -07:00
Johannes Schindelin
920f22e6bc merge: allow reading the merge commit message from a file
This is consistent with `git commit` which, like `git merge`, supports
passing the commit message via `-m <msg>` and, unlike `git merge` before
this patch, via `-F <file>`.

It is useful to allow this for scripted use, or for the upcoming patch
to allow (re-)creating octopus merges in `git rebase --rebase-merges`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-11 14:47:05 -07:00
Elijah Newren
55f39cf755 merge: fix misleading pre-merge check documentation
builtin/merge.c contains this important requirement for merge strategies:

    ...the index must be in sync with the head commit.  The strategies are
    responsible to ensure this.

However, Documentation/git-merge.txt says:

    ...[merge will] abort if there are any changes registered in the index
    relative to the `HEAD` commit.  (One exception is when the changed
    index entries are in the state that would result from the merge
    already.)

Interestingly, prior to commit c0be8aa06b ("Documentation/git-merge.txt:
Partial rewrite of How Merge Works", 2008-07-19),
Documentation/git-merge.txt said much more:

    ...the index file must match the tree of `HEAD` commit...
    [NOTE]
    This is a bit of a lie.  In certain special cases [explained
    in detail]...
    Otherwise, merge will refuse to do any harm to your repository
    (that is...your working tree...and index are left intact).

So, this suggests that the exceptions existed because there were special
cases where it would case no harm, and potentially be slightly more
convenient for the user.  While the current text in git-merge.txt does
list a condition under which it would be safe to proceed despite the index
not matching HEAD, it does not match what is actually implemented, in
three different ways:

    * The exception is written to describe what unpack-trees allows.  Not
      all merge strategies allow such an exception, though, making this
      description misleading.  'ours' and 'octopus' merges have strictly
      enforced index==HEAD for a while, and the commit previous to this
      one made 'recursive' do so as well.

    * If someone did a three-way content merge on a specific file using
      versions from the relevant commits and staged it prior to running
      merge, then that path would technically satisfy the exception listed
      in git-merge.txt.  unpack-trees.c would still error out on the path,
      though, because it defers the three-way content merge logic to other
      parts of the code (resolve, octopus, or recursive) and has no way of
      checking whether the index entry from before the merge will match
      the end result of the merge.

    * The exception as implemented in unpack-trees actually only checked
      that the index matched the MERGE_HEAD version of the file and that
      HEAD matched the merge base.  Assuming no renames, that would indeed
      provide cases where the index matches the end result we'd get from a
      merge.  But renames means unpack-trees is checking that it instead
      matches something other than what the final result will be, risking
      either erroring out when we shouldn't need to, or not erroring out
      when we should and overwriting the user's staged changes.

In addition to the wording behind this exception being misleading, it is
also somewhat surprising to see how many times the code for the special
cases were wrong or the check to make sure the index matched head was
forgotten altogether:

* Prior to commit ee6566e8d7 ("[PATCH] Rewrite read-tree", 2005-09-05),
  there were many cases where an unclean index entry was allowed (look for
  merged_entry_allow_dirty()); it appears that in those cases, the merge
  would have simply overwritten staged changes with the result of the
  merge.  Thus, the merge result would have been correct, but the user's
  uncommitted changes could be thrown away without warning.

* Prior to commit 160252f816 ("git-merge-ours: make sure our index
  matches HEAD", 2005-11-03), the 'ours' merge strategy did not check
  whether the index matched HEAD.  If it didn't, the resulting merge
  would include all the staged changes, and thus wasn't really an 'ours'
  strategy.

* Prior to commit 3ec62ad9ff ("merge-octopus: abort if index does not
  match HEAD", 2016-04-09), 'octopus' merges did not check whether the
  index matched HEAD, also resulting in any staged changes from before
  the commit silently being folded into the resulting merge.  commit
  a6ee883b8e ("t6044: new merge testcases for when index doesn't match
  HEAD", 2016-04-09) was also added at the same time to try to test to
  make sure all strategies did the necessary checking for the requirement
  that the index match HEAD.  Sadly, it didn't catch all the cases, as
  evidenced by the remainder of this list...

* Prior to commit 65170c07d4 ("merge-recursive: avoid incorporating
  uncommitted changes in a merge", 2017-12-21), merge-recursive simply
  relied on unpack_trees() to do the necessary check, but in one special
  case it avoided calling unpack_trees() entirely and accidentally ended
  up silently including any staged changes from before the merge in the
  resulting merge commit.

* The commit immediately before this one in this series noted that the
  exceptions were written in a way that assumed no renames, making it
  unsafe for merge-recursive to use.  merge-recursive was modified to
  use its own check to enforce that index==HEAD.

This history makes it very tempting to go into builtin/merge.c and replace
the comment that strategies must enforce that index matches HEAD with code
that just enforces it.  At this point, that would only affect the
'resolve' strategy; all other strategies have each been modified to
manually enforce it.  (However, note that index==HEAD is not strictly
enforced for fast-forward merges, as those are not considered a merge
strategy and they trigger in builtin/merge.c before the section in the
code where the relevant comment is found.)

But, even if we don't take the step of just fixing these problems by
enforcing index==HEAD for all strategies, we at least need to update this
misleading documentation in git-merge.txt.  For now, just modify the claim
in Documentation/git-merge.txt to fix the error.  The precise details
around combination of merges strategies and special cases probably is not
relevant to most users, so simply state that exceptions may exist but are
narrow and vary depending upon which merge strategy is in use.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-11 09:38:36 -07:00
Taylor Blau
9d8db06eb4 grep.c: teach 'git grep --only-matching'
Teach 'git grep --only-matching', a new option to only print the
matching part(s) of a line.

For instance, a line containing the following (taken from README.md:27):

  (`man gitcvs-migration` or `git help cvs-migration` if git is

Is printed as follows:

  $ git grep --line-number --column --only-matching -e git -- \
    README.md | grep ":27"
  README.md:27:7:git
  README.md:27:16:git
  README.md:27:38:git

The patch works mostly as one would expect, with the exception of a few
considerations that are worth mentioning here.

Like GNU grep, this patch ignores --only-matching when --invert (-v) is
given. There is a sensible answer here, but parity with the behavior of
other tools is preferred.

Because a line might contain more than one match, there are special
considerations pertaining to when to print line headers, newlines, and
how to increment the match column offset. The line header and newlines
are handled as a special case within the main loop to avoid polluting
the surrounding code with conditionals that have large blocks.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09 14:15:28 -07:00
Jonathan Tan
a0c9016abd upload-pack: send refs' objects despite "filter"
A filter line in a request to upload-pack filters out objects regardless
of whether they are directly referenced by a "want" line or not. This
means that cloning with "--filter=blob:none" (or another filter that
excludes blobs) from a repository with at least one ref pointing to a
blob (for example, the Git repository itself) results in output like the
following:

    error: missing object referenced by 'refs/tags/junio-gpg-pub'

and if that particular blob is not referenced by a fetched tree, the
resulting clone fails fsck because there is no object from the remote to
vouch that the missing object is a promisor object.

Update both the protocol and the upload-pack implementation to include
all explicitly specified "want" objects in the packfile regardless of
the filter specification.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09 12:37:38 -07:00
brian m. carlson
e67a228cd8 send-email: automatically determine transfer-encoding
git send-email, when invoked without a --transfer-encoding option, sends
8bit data without a MIME version or a transfer encoding.  This has
several downsides.

First, unless the transfer encoding is specified, it defaults to 7bit,
meaning that non-ASCII data isn't allowed.  Second, if lines longer than
998 bytes are used, we will send an message that is invalid according to
RFC 5322.  The --validate option, which is the default, catches this
issue, but it isn't clear to many people how to resolve this.

To solve these issues, default the transfer encoding to "auto", so that
we explicitly specify 8bit encoding when lines don't exceed 998 bytes
and quoted-printable otherwise.  This means that we now always emit
Content-Transfer-Encoding and MIME-Version headers, so remove the
conditionals from this portion of the code.

It is unlikely that the unconditional inclusion of these two headers
will affect the deliverability of messages in anything but a positive
way, since MIME is already widespread and well understood by most email
programs.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09 10:55:12 -07:00
brian m. carlson
fa29f36d99 docs: correct RFC specifying email line length
The git send-email documentation specifies RFC 2821 (the SMTP RFC) as
providing line length limits, but the specification that restricts line
length to 998 octets is RFC 2822 (the email message format RFC).  Since
RFC 2822 has been obsoleted by RFC 5322, update the text to refer to RFC
5322 instead of RFC 2821.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09 10:55:12 -07:00
brian m. carlson
f2d06fb13f send-email: accept long lines with suitable transfer encoding
With --validate (which is the default), we warn about lines exceeding
998 characters due to the limits specified in RFC 5322.  However, if
we're using a suitable transfer encoding (quoted-printable or base64),
we're guaranteed not to have lines exceeding 76 characters, so there's
no need to fail in this case.  The auto transfer encoding handles this
specific case, so accept it as well.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09 10:55:12 -07:00
brian m. carlson
7a36987fff send-email: add an auto option for transfer encoding
For most patches, using a transfer encoding of 8bit provides good
compatibility with most servers and makes it as easy as possible to view
patches.  However, there are some patches for which 8bit is not a valid
encoding: RFC 5322 specifies that a message must not have lines
exceeding 998 octets.

Add a transfer encoding value, auto, which indicates that a patch should
use 8bit where allowed and quoted-printable otherwise.  Choose
quoted-printable instead of base64, since base64-encoded plain text is
treated as suspicious by some spam filters.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-09 10:55:12 -07:00
Jonathan Tan
3390e42adb fetch-pack: support negotiation tip whitelist
During negotiation, fetch-pack eventually reports as "have" lines all
commits reachable from all refs. Allow the user to restrict the commits
sent in this way by providing a whitelist of tips; only the tips
themselves and their ancestors will be sent.

Both globs and single objects are supported.

This feature is only supported for protocols that support connect or
stateless-connect (such as HTTP with protocol v2).

This will speed up negotiation when the repository has multiple
relatively independent branches (for example, when a repository
interacts with multiple repositories, such as with linux-next [1] and
torvalds/linux [2]), and the user knows which local branch is likely to
have commits in common with the upstream branch they are fetching.

[1] https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next/
[2] https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-03 15:00:41 -07:00