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>
... just like the Perl version ;-)
Note that this requires the `get_add_i_color()` function being defined
globally, which is the entire reason why we gave it such a descriptive
name in the first place.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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>
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 we also remember which previous/next hunk was undecided, rather than
looking again when the user asked to jump there).
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.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This is hardly the first conversion of a Git command that is implemented
as a script to a built-in. So far, the most successful strategy for such
conversions has been to add a built-in helper and call that for more and
more functionality from the script, as more and more parts are
converted.
With the interactive add, we choose a different strategy. The sole
reason for this is that on Windows (where such a conversion has the most
benefits in terms of speed and robustness) we face the very specific
problem that a `system()` call in Perl seems to close `stdin` in the
parent process when the spawned process consumes even one character from
`stdin`. And that just does not work for us here, as it would stop the
main loop as soon as any interactive command was performed by the
helper. Which is almost all of the commands in `git add -i`.
It is almost as if Perl told us once again that it does not want us to
use it on Windows.
Instead, we follow the opposite route where we start with a bare-bones
version of the built-in interactive add, guarded by the new
`add.interactive.useBuiltin` config variable, and then add more and more
functionality to it, until it is feature complete.
At this point, the built-in version of `git add -i` only states that it
cannot do anything yet ;-)
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
