Commit Graph

57339 Commits

Author SHA1 Message Date
Johannes Schindelin
2c8bd8471a checkout -p: handle new files correctly
The original patch selection code was written for `git add -p`, and the
fundamental unit on which it works is a hunk.

We hacked around that to handle deletions back in 24ab81ae4d
(add-interactive: handle deletion of empty files, 2009-10-27). But `git
add -p` would never see a new file, since we only consider the set of
tracked files in the index.

However, since the same machinery was used for `git checkout -p` &
friends, we can see new files.

Handle this case specifically, adding a new prompt for it that is
modeled after the `deleted file` case.

This also fixes the problem where added _empty_ files could not be
staged via `git checkout -p`.

Reported-by: Merlin Büge <toni@bluenox07.de>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-27 14:50:20 -07:00
Johannes Schindelin
b2627cc3d4 ci: include the built-in git add -i in the linux-gcc job
This job runs the test suite twice, once in regular mode, and once with
a whole slew of `GIT_TEST_*` variables set.

Now that the built-in version of `git add --interactive` is
feature-complete, let's also throw `GIT_TEST_ADD_I_USE_BUILTIN` into
that fray.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
12acdf573a built-in add -p: handle Escape sequences more efficiently
When `interactive.singlekey = true`, we react immediately to keystrokes,
even to Escape sequences (e.g. when pressing a cursor key).

The problem with Escape sequences is that we do not really know when
they are done, and as a heuristic we poll standard input for half a
second to make sure that we got all of it.

While waiting half a second is not asking for a whole lot, it can become
quite annoying over time, therefore with this patch, we read the
terminal capabilities (if available) and extract known Escape sequences
from there, then stop polling immediately when we detected that the user
pressed a key that generated such a known sequence.

This recapitulates the remaining part of b5cc003253 (add -i: ignore
terminal escape sequences, 2011-05-17).

Note: We do *not* query the terminal capabilities directly. That would
either require a lot of platform-specific code, or it would require
linking to a library such as ncurses.

Linking to a library in the built-ins is something we try very hard to
avoid (we even kicked the libcurl dependency to a non-built-in remote
helper, just to shave off a tiny fraction of a second from Git's startup
time). And the platform-specific code would be a maintenance nightmare.

Even worse: in Git for Windows' case, we would need to query MSYS2
pseudo terminals, which `git.exe` simply cannot do (because it is
intentionally *not* an MSYS2 program).

To address this, we simply spawn `infocmp -L -1` and parse its output
(which works even in Git for Windows, because that helper is included in
the end-user facing installations).

This is done only once, as in the Perl version, but it is done only when
the first Escape sequence is encountered, not upon startup of `git add
-i`; This saves on startup time, yet makes reacting to the first Escape
sequence slightly more sluggish. But it allows us to keep the
terminal-related code encapsulated in the `compat/terminal.c` file.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
e118f06396 built-in add -p: handle Escape sequences in interactive.singlekey mode
This recapitulates part of b5cc003253 (add -i: ignore terminal escape
sequences, 2011-05-17):

    add -i: ignore terminal escape sequences

    On the author's terminal, the up-arrow input sequence is ^[[A, and
    thus fat-fingering an up-arrow into 'git checkout -p' is quite
    dangerous: git-add--interactive.perl will ignore the ^[ and [
    characters and happily treat A as "discard everything".

    As a band-aid fix, use Term::Cap to get all terminal capabilities.
    Then use the heuristic that any capability value that starts with ^[
    (i.e., \e in perl) must be a key input sequence.  Finally, given an
    input that starts with ^[, read more characters until we have read a
    full escape sequence, then return that to the caller.  We use a
    timeout of 0.5 seconds on the subsequent reads to avoid getting stuck
    if the user actually input a lone ^[.

    Since none of the currently recognized keys start with ^[, the net
    result is that the sequence as a whole will be ignored and the help
    displayed.

Note that we leave part for later which uses "Term::Cap to get all
terminal capabilities", for several reasons:

1. it is actually not really necessary, as the timeout of 0.5 seconds
   should be plenty sufficient to catch Escape sequences,

2. it is cleaner to keep the change to special-case Escape sequences
   separate from the change that reads all terminal capabilities to
   speed things up, and

3. in practice, relying on the terminal capabilities is a bit overrated,
   as the information could be incomplete, or plain wrong. For example,
   in this developer's tmux sessions, the terminal capabilities claim
   that the "cursor up" sequence is ^[M, but the actual sequence
   produced by the "cursor up" key is ^[[A.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
04f816b125 built-in add -p: respect the interactive.singlekey config setting
The Perl version of `git add -p` supports this config setting to allow
users to input commands via single characters (as opposed to having to
press the <Enter> key afterwards).

This is an opt-in feature because it requires Perl packages
(Term::ReadKey and Term::Cap, where it tries to handle an absence of the
latter package gracefully) to work. Note that at least on Ubuntu, that
Perl package is not installed by default (it needs to be installed via
`sudo apt-get install libterm-readkey-perl`), so this feature is
probably not used a whole lot.

In C, we obviously do not have these packages available, but we just
introduced `read_single_keystroke()` that is similar to what
Term::ReadKey provides, and we use that here.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
a5e46e6b01 terminal: add a new function to read a single keystroke
Typically, input on the command-line is line-based. It is actually not
really easy to get single characters (or better put: keystrokes).

We provide two implementations here:

- One that handles `/dev/tty` based systems as well as native Windows.
  The former uses the `tcsetattr()` function to put the terminal into
  "raw mode", which allows us to read individual keystrokes, one by one.
  The latter uses `stty.exe` to do the same, falling back to direct
  Win32 Console access.

  Thanks to the refactoring leading up to this commit, this is a single
  function, with the platform-specific details hidden away in
  conditionally-compiled code blocks.

- A fall-back which simply punts and reads back an entire line.

Note that the function writes the keystroke into an `strbuf` rather than
a `char`, in preparation for reading Escape sequences (e.g. when the
user hit an arrow key). This is also required for UTF-8 sequences in
case the keystroke corresponds to a non-ASCII letter.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
9ea416cb51 terminal: accommodate Git for Windows' default terminal
Git for Windows' Git Bash runs in MinTTY by default, which does not have
a Win32 Console instance, but uses MSYS2 pseudo terminals instead.

This is a problem, as Git for Windows does not want to use the MSYS2
emulation layer for Git itself, and therefore has no direct way to
interact with that pseudo terminal.

As a workaround, use the `stty` utility (which is included in Git for
Windows, and which *is* an MSYS2 program, so it knows how to deal with
the pseudo terminal).

Note: If Git runs in a regular CMD or PowerShell window, there *is* a
regular Win32 Console to work with. This is not a problem for the MSYS2
`stty`: it copes with this scenario just fine.

Also note that we introduce support for more bits than would be
necessary for a mere `disable_echo()` here, in preparation for the
upcoming `enable_non_canonical()` function.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
94ac3c31f7 terminal: make the code of disable_echo() reusable
We are about to introduce the function `enable_non_canonical()`, which
shares almost the complete code with `disable_echo()`.

Let's prepare for that, by refactoring out that shared code.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:17 -08:00
Johannes Schindelin
08b1ea4c39 built-in add -p: handle diff.algorithm
The Perl version of `git add -p` reads the config setting
`diff.algorithm` and if set, uses it to generate the diff using the
specified algorithm.

This patch ports that functionality to the C version.

Note: just like `git-add--interactive.perl`, we do _not_ respect this
config setting in `git add -i`'s `diff` command, but _only_ in the
`patch` command.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:16 -08:00
Johannes Schindelin
180f48df69 built-in add -p: support interactive.diffFilter
The Perl version supports post-processing the colored diff (that is
generated in addition to the uncolored diff, intended to offer a
prettier user experience) by a command configured via that config
setting, and now the built-in version does that, too.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:16 -08:00
Johannes Schindelin
1e4ffc765d t3701: adjust difffilter test
In 42f7d45428 (add--interactive: detect bogus diffFilter output,
2018-03-03), we added a test case that verifies that the diffFilter
feature complains appropriately when the output is too short.

In preparation for the upcoming change where the built-in `add -p` is
taught to respect that setting, let's adjust that test a little. The
problem is that `echo too-short` is configured as diffFilter, and it
does not read the `stdin`. When calling it through `pipe_command()`, it
is therefore possible that we try to feed the `diff` to it while it is
no longer listening, and we receive a `SIGPIPE`.

The Perl code apparently handles this in a way similar to an
end-of-file, but taking a step back, we realize that a diffFilter that
does not even _look_ at its standard input is very unrealistic. The
entire point of this feature is to transform the diff, not to ignore it
altogether.

So let's modify the test case to reflect that insight: instead of
printing some bogus text, let's use a diffFilter that deletes the first
line of the diff instead.

This still tests for the same thing, but it does not confuse the
built-in `add -p` with that `SIGPIPE`.

Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 12:06:16 -08:00
Johannes Schindelin
c480eeb574 commit --interactive: make it work with the built-in add -i
The built-in `git add -i` machinery obviously has its `the_repository`
structure initialized at the point where `cmd_commit()` calls it, and
therefore does not look at the environment variable `GIT_INDEX_FILE`.

But when being called from `commit --interactive`, it has to, because
the index was already locked in that case, and we want to ask the
interactive add machinery to work on the `index.lock` file instead of
the `index` file.

Technically, we could teach `run_add_i()`, or for that matter
`run_add_p()`, to look specifically at that environment variable, but
the entire idea of passing in a parameter of type `struct repository *`
is to allow working on multiple repositories (and their index files)
independently.

So let's instead override the `index_file` field of that structure
temporarily.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:22 -08:00
Johannes Schindelin
cee6cb7300 built-in add -p: implement the "worktree" patch modes
This is a straight-forward port of 2f0896ec3a (restore: support
--patch, 2019-04-25) which added support for `git restore -p`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:22 -08:00
Johannes Schindelin
52628f94fc built-in add -p: implement the "checkout" patch modes
This patch teaches the built-in `git add -p` machinery all the tricks it
needs to know in order to act as the work horse for `git checkout -p`.

Apart from the minor changes (slightly reworded messages, different
`diff` and `apply --check` invocations), it requires a new function to
actually apply the changes, as `git checkout -p` is a bit special in
that respect: when the desired changes do not apply to the index, but
apply to the work tree, Git does not fail straight away, but asks the
user whether to apply the changes to the worktree at least.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:22 -08:00
Johannes Schindelin
6610e4628a built-in stash: use the built-in git add -p if so configured
The scripted version of `git stash` called directly into the Perl script
`git-add--interactive.perl`, and this was faithfully converted to C.

However, we have a much better way to do this now: call the internal API
directly, which will now incidentally also respect the
`add.interactive.useBuiltin` setting. Let's just do this.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:21 -08:00
Johannes Schindelin
90a6bb98d1 legacy stash -p: respect the add.interactive.usebuiltin setting
As `git add` traditionally did not expose the `--patch=<mode>` modes via
command-line options, the scripted version of `git stash` had to call
`git add--interactive` directly.

But this prevents the built-in `add -p` from kicking in, as
`add--interactive` is the scripted version (which does not have a
"fall-back" to the built-in version).

So let's introduce support for internal switch for `git add` that the
scripted `git stash` can use to call the appropriate backend (scripted
or built-in, depending on `add.interactive.useBuiltin`).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:21 -08:00
Johannes Schindelin
36bae1dc0e built-in add -p: implement the "stash" and "reset" patch modes
The `git stash` and `git reset` commands support a `--patch` option, and
both simply hand off to `git add -p` to perform that work. Let's teach
the built-in version of that command to be able to perform that work, too.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:21 -08:00
Johannes Schindelin
d2a233cb8b built-in add -p: prepare for patch modes other than "stage"
The Perl script backing `git add -p` is used not only for that command,
but also for `git stash -p`, `git reset -p` and `git checkout -p`.

In preparation for teaching the C version of `git add -p` to support
also the latter commands, let's abstract away what is "stage" specific
into a dedicated data structure describing the differences between the
patch modes.

Finally, please note that the Perl version tries to make sure that the
diffs are only generated for the modified files. This is not actually
necessary, as the calls to Git's diff machinery already perform that
work, and perform it well. This makes it unnecessary to port the
`FILTER` field of the `%patch_modes` struct, as well as the
`get_diff_reference()` function.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-21 16:06:21 -08:00
Johannes Schindelin
2e4083198d built-in add -p: show helpful hint when nothing can be staged
This patch will make `git add -p` show "No changes." or "Only binary
files changed." in that case.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
54d9d9b2ee built-in add -p: only show the applicable parts of the help text
When displaying the only hunk in a file's diff, the prompt already
excludes the commands to navigate to the previous/next hunk.

Let's also let the `?` command show only the help lines corresponding to
the commands that are displayed in the prompt.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
ade246efed built-in add -p: implement the 'q' ("quit") command
This command is actually very similar to the 'd' ("do not stage this
hunk or any of the later hunks in the file") command: it just does
something on top, namely leave the loop and return a value indicating
that we're quittin'.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
d6cf873340 built-in add -p: implement the '/' ("search regex") command
This patch implements the hunk searching feature in the C version of
`git add -p`.

A test is added to verify that this behavior matches the one of the Perl
version of `git add -p`.

Note that this involves a change of behavior: the Perl version uses (of
course) the Perl flavor of regular expressions, while this patch uses
the regcomp()/regexec(), i.e. POSIX extended regular expressions. In
practice, this behavior change is unlikely to matter.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
9254bdfb4f built-in add -p: implement the 'g' ("goto") command
With this patch, it is now possible to see a summary of the available
hunks and to navigate between them (by number).

A test is added to verify that this behavior matches the one of the Perl
version of `git add -p`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
bcdd297b78 built-in add -p: implement hunk editing
Just like `git add --edit` allows the user to edit the diff before it is
being applied to the index, this feature allows the user to edit the
diff *hunk*.

Naturally, it gets a bit more complicated here because the result has
to play well with the remaining hunks of the overall diff. Therefore,
we have to do a loop in which we let the user edit the hunk, then test
whether the result would work, and if not, drop the edits and let the
user decide whether to try editing the hunk again.

Note: in contrast to the Perl version, we use the same diff
"coalescing" (i.e. merging overlapping hunks into a single one) also for
the check after editing, and we introduce a new flag for that purpose
that asks the `reassemble_patch()` function to pretend that all hunks
were selected for use.

This allows us to continue to run `git apply` *without* the
`--allow-overlap` option (unlike the Perl version), and it also fixes
two known breakages in `t3701-add-interactive.sh` (which we cannot mark
as resolved so far because the Perl script version is still the default
and continues to have those breakages).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
b38dd9e715 strbuf: add a helper function to call the editor "on an strbuf"
This helper supports the scenario where Git has a populated `strbuf` and
wants to let the user edit it interactively.

In `git add -p`, we will use this to allow interactive hunk editing: the
diff hunks are already in memory, but we need to write them out to a
file so that an editor can be launched, then read everything back once
the user is done editing.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
11f2c0dae8 built-in add -p: coalesce hunks after splitting them
This is considered "the right thing to do", according to 933e44d3a0
("add -p": work-around an old laziness that does not coalesce hunks,
2011-04-06).

Note: we cannot simply modify the hunks while merging them; Once we
implement hunk editing, we will call `reassemble_patch()` whenever a
hunk is edited, therefore we must not modify the hunks (because the user
might e.g. hit `K` and change their mind whether to stage the previous
hunk).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
510aeca199 built-in add -p: implement the hunk splitting feature
If this developer's workflow is any indication, then this is *the* most
useful feature of Git's interactive `add `command.

Note: once again, this is not a verbatim conversion from the Perl code
to C: the `hunk_splittable()` function, for example, essentially did all
the work of splitting the hunk, just to find out whether more than one
hunk would have been the result (and then tossed that result into the
trash). In C we instead count the number of resulting hunks (without
actually doing the work of splitting, but just counting the transitions
from non-context lines to context lines), and store that information
with the hunk, and we do that *while* parsing the diff in the first
place.

Another deviation: the built-in `git add -p` was designed with a single
strbuf holding the diff (and another one holding the colored diff, if
that one was asked for) in mind, and hunks essentially store just the
start and end offsets pointing into that strbuf. As a consequence, when
we split hunks, we now use a special mode where the hunk header is
generated dynamically, and only the rest of the hunk is stored using
such start/end offsets. This way, we also avoid the frequent
formatting/re-parsing of the hunk header of the Perl version.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
0ecd9d27fc built-in add -p: show different prompts for mode changes and deletions
Just like the Perl version, we now helpfully ask the user whether they
want to stage a mode change, or a deletion.

Note that we define the prompts in an array, in preparation for a later
patch that changes those prompts to yet different versions for `git
reset -p`, `git stash -p` and `git checkout -p` (which all call the `git
add -p` machinery to do the actual work).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
5906d5de77 built-in app -p: allow selecting a mode change as a "hunk"
This imitates the way the Perl version treats mode changes: it offers
the mode change up for the user to decide, as if it was a diff hunk.

In contrast to the Perl version, we make use of the fact that the mode
line is the first hunk, and explicitly strip out that line from the diff
header if that "hunk" was not selected to be applied, and skipping that
hunk while coalescing the diff. The Perl version plays some kind of diff
line lego instead.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:14 -08:00
Johannes Schindelin
47dc4fd5eb built-in add -p: handle deleted empty files
This addresses the same problem as 24ab81ae4d (add-interactive: handle
deletion of empty files, 2009-10-27), although in a different way: we
not only stick the "deleted file" line into its own pseudo hunk, but
also the entire remainder (if any) of the same diff.

That way, we do not have to play any funny games with regards to
coalescing the diff after the user selected what (possibly pseudo-)hunks
to stage.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
80399aec5a built-in add -p: support multi-file diffs
For simplicity, the initial implementation in C handled only a single
modified file. Now it handles an arbitrary number of files.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
7584dd3c66 built-in add -p: offer a helpful error message when hunk navigation failed
... just like the Perl version currently does...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
12c24cf850 built-in add -p: color the prompt and the help text
... just like the Perl version ;-)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
25ea47af49 built-in add -p: adjust hunk headers as needed
When skipping a hunk that adds a different number of lines than it
removes, we need to adjust the subsequent hunk headers of non-skipped
hunks: in pathological cases, the context is not enough to determine
precisely where the patch should be applied.

This problem was identified in 23fea4c240 (t3701: add failing test for
pathological context lines, 2018-03-01) and fixed in the Perl version in
fecc6f3a68 (add -p: adjust offsets of subsequent hunks when one is
skipped, 2018-03-01).

And this patch fixes it in the C version of `git add -p`.

In contrast to the Perl version, we try to keep the extra text on the
hunk header (which typically contains the signature of the function
whose code is changed in the hunk) intact.

Note: while the C version does not support staging mode changes at this
stage, we already prepare for this by simply skipping the hunk header if
both old and new offset is 0 (this cannot happen for regular hunks, and
we will use this as an indicator that we are looking at a special hunk).

Likewise, we already prepare for hunk splitting by handling the absence
of extra text in the hunk header gracefully: only the first split hunk
will have that text, the others will not (indicated by an empty extra
text start/end range). Preparing for hunk splitting already at this
stage avoids an indentation change of the entire hunk header-printing
block later, and is almost as easy to review as without that handling.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
e3bd11b4eb built-in add -p: show colored hunks by default
Just like the Perl version, we now generate two diffs if `color.diff` is
set: one with and one without color. Then we parse them in parallel and
record which hunks start at which offsets in both.

Note that this is a (slight) deviation from the way the Perl version did
it: we are no longer reading the output of `diff-files` line by line
(which is more natural for Perl than for C), but in one go, and parse
everything later, so we might just as well do it in synchrony.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
1942ee44e8 built-in add -i: wire up the new C code for the patch command
The code in `git-add--interactive.perl` that takes care of the `patch`
command can look quite intimidating. There are so many modes in which it
can be called, for example.

But for the `patch` command in `git add -i`, only one mode is relevant:
the `stage` mode. And we just implemented the beginnings of that mode in
C so far. So let's use it when `add.interactive.useBuiltin=true`.

Now, while the code in `add-patch.c` is far from reaching feature parity
with the code in `git-add--interactive.perl` (color is not implemented,
the diff algorithm cannot be configured, the colored diff cannot be
post-processed via `interactive.diffFilter`, many commands are
unimplemented yet, etc), hooking it all up with the part of `git add -i`
that is already converted to C makes it easier to test and develop it.

Note: at this stage, both the `add.interactive.useBuiltin` config
setting is still safely opt-in, and will probably be fore quite some
time, to allow for thorough testing "in the wild" without adversely
affecting existing users.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
f6aa7ecc34 built-in add -i: start implementing the patch functionality in C
In the previous steps, we re-implemented the main loop of `git add -i`
in C, and most of the commands.

Notably, we left out the actual functionality of `patch`, as the
relevant code makes up more than half of `git-add--interactive.perl`,
and is actually pretty independent of the rest of the commands.

With this commit, we start to tackle that `patch` part. For better
separation of concerns, we keep the code in a separate file,
`add-patch.c`. The new code is still guarded behind the
`add.interactive.useBuiltin` config setting, and for the moment,
it can only be called via `git add -p`.

The actual functionality follows the original implementation of
5cde71d64a (git-add --interactive, 2006-12-10), but not too closely
(for example, we use string offsets rather than copying strings around,
and after seeing whether the `k` and `j` commands are applicable, in the
C version we remember which previous/next hunk was undecided, and use it
rather than looking again when the user asked to jump).

As a further deviation from that commit, We also use a comma instead of
a slash to separate the available commands in the prompt, as the current
version of the Perl script does this, and we also add a line about the
question mark ("print help") to the help text.

While it is tempting to use this conversion of `git add -p` as an excuse
to work on `apply_all_patches()` so that it does _not_ want to read a
file from `stdin` or from a file, but accepts, say, an `strbuf` instead,
we will refrain from this particular rabbit hole at this stage.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13 12:37:13 -08:00
Johannes Schindelin
b4bbbbd5a2 apply --allow-overlap: fix a corner case
Yes, yes, this is supposed to be only a band-aid option for `git add -p`
not Doing The Right Thing. But as long as we carry the `--allow-overlap`
option, we might just as well get it right.

This fixes the case where one hunk inserts a line before the first line,
and is followed by a hunk whose context overlaps with the first one's
and which appends a line at the end.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:34 -08:00
Johannes Schindelin
89c8559367 git add -p: use non-zero exit code when the diff generation failed
The first thing `git add -p` does is to generate a diff. If this diff
cannot be generated, `git add -p` should not continue as if nothing
happened, but instead fail.

What we *actually* do here is much broader: we now verify for *every*
`run_cmd_pipe()` call that the spawned process actually succeeded.

Note that we have to change two callers in this patch, as we need to
store the spawned process' output in a local variable, which means that
the callers can no longer decide whether to interpret the `return <$fh>`
in array or in scalar context.

This bug was noticed while writing a test case for the diff.algorithm
feature, and we let that test case double as a regression test for this
fixed bug, too.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:34 -08:00
Johannes Schindelin
e91162be9c t3701: verify that the diff.algorithm config setting is handled
Without this patch, there is actually no test in Git's test suite that
covers the diff.algorithm feature. Let's add one.

We do this by passing a bogus value and then expecting `git diff-files`
to produce the appropriate error message.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:34 -08:00
Johannes Schindelin
0c3222c4f3 t3701: verify the shown messages when nothing can be added
In preparation for re-implementing `git add -p` in pure C (where we will
purposefully keep the implementation of `git add -p` separate from the
implementation of `git add -i`), let's verify that the user is told the
same things as in the Perl version when the diff file is either empty or
contains only entries about binary files.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:34 -08:00
Johannes Schindelin
24be352d52 t3701: add a test for the different add -p prompts
The `git add -p` command offers different prompts for regular diff hunks
vs mode change pseudo hunks vs diffs deleting files.

Let's cover this in the regresion test suite, in preparation for
re-implementing `git add -p` in C.

For the mode change prompt, we use a trick that lets this test case pass
even on systems without executable bit, i.e. where `core.filemode =
false` (such as Windows): we first add the file to the index with `git
add --chmod=+x`, and then call `git add -p` with `core.filemode` forced
to `true`. The file on disk has no executable bit set, therefore we will
see a mode change.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:34 -08:00
Johannes Schindelin
8539b46534 t3701: avoid depending on the TTY prerequisite
The TTY prerequisite is a rather heavy one: it not only requires Perl to
work, but also the IO/Pty.pm module (with native support, and it
requires pseudo terminals, too).

In particular, test cases marked with the TTY prerequisite would be
skipped in Git for Windows' SDK.

In the case of `git add -p`, we do not actually need that big a hammer,
as we do not want to test any functionality that requires a pseudo
terminal; all we want is for the interactive add command to use color,
even when being called from within the test suite.

And we found exactly such a trick earlier already: when we added a test
case to verify that the main loop of `git add -i` is colored
appropriately. Let's use that trick instead of the TTY prerequisite.

While at it, we avoid the pipes, as we do not want a SIGPIPE to break
the regression test cases (which will be much more likely when we do not
run everything through Perl because that is inherently slower).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:33 -08:00
Johannes Schindelin
0f0fba2cc8 t3701: add a test for advanced split-hunk editing
In this developer's workflows, it often happens that a hunk needs to be
edited in a way that adds lines, and sometimes even reduces the number
of context lines.

Let's add a regression test for this.

Note that just like the preceding test case, the new test case is *not*
handled gracefully by the current `git add -p`. It will be handled
correctly by the upcoming built-in `git add -p`, though.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-06 08:57:33 -08:00
Johannes Schindelin
2e697ced9d built-in add -i: offer the quit command
We do not really want to `exit()` here, of course, as this is safely
libified code.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-01 07:30:54 -08:00
Johannes Schindelin
d7633578b5 built-in add -i: re-implement the diff command
It is not only laziness that we simply spawn `git diff -p --cached`
here: this command needs to use the pager, and the pager needs to exit
when the diff is done. Currently we do not have any way to make that
happen if we run the diff in-process. So let's just spawn.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-01 07:30:54 -08:00
Johannes Schindelin
8746e07277 built-in add -i: implement the patch command
Well, it is not a full implementation yet. In the interest of making
this easy to review (and easy to keep bugs out), we still hand off to
the Perl script to do the actual work.

The `patch` functionality actually makes up for more than half of the
1,800+ lines of `git-add--interactive.perl`. It will be ported from Perl
to C incrementally, later.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-01 07:30:54 -08:00
Johannes Schindelin
ab1e1cccaf built-in add -i: re-implement add-untracked in C
This is yet another command, ported to C. It builds nicely on the
support functions introduced for other commands, with the notable
difference that only names are displayed for untracked files, no
file type or diff summary.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-01 07:30:54 -08:00
Johannes Schindelin
c54ef5e424 built-in add -i: re-implement revert in C
This is a relatively straight-forward port from the Perl version, with
the notable exception that we imitate `git reset -- <paths>` in the C
version rather than the convoluted `git ls-tree HEAD -- <paths> | git
update-index --index-info` followed by `git update-index --force-remove
-- <paths>` for the missed ones.

While at it, we fix the pretty obvious bug where the `revert` command
offers to unstage files that do not have staged changes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-01 07:30:54 -08:00
Johannes Schindelin
a8c45be939 built-in add -i: implement the update command
After `status` and `help`, it is now time to port the `update` command
to C, the second command that is shown in the main loop menu of `git add
-i`.

This `git add -i` command is the first one which lets the user choose a
subset of a list of files, and as such, this patch lays the groundwork
for the other commands of that category:

- It teaches the `print_file_item()` function to show a unique prefix
  if we found any (the code to find it had been added already in the
  previous patch where we colored the unique prefixes of the main loop
  commands, but that patch uses the `print_command_item()` function to
  display the menu items).

- This patch also adds the help text that is shown when the user input
  to select items from the shown list could not be parsed.

- As `get_modified_files()` clears the list of files, it now has to take
  care of clearing the _full_ `prefix_item_list` lest the `sorted` and
  `selected` fields go stale and inconsistent.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-01 07:30:54 -08:00