Doing diffs for merges are special; they should typically avoid history
simplification. For example, with
git log --diff-merges=first-parent -- path
the default history simplification would remove merge commits from
consideration if the file "path" matched the second parent. That is
counter to what the user wants when looking for first-parent diffs.
Similar comments can be made for --diff-merges=separate (which diffs
against both parents) and --diff-merges=remerge (which diffs against a
remerge of the merge commit).
However, history simplification still makes sense if not doing diffing
merges, and it also makes sense for the combined and dense-combined
forms of diffing merges (because both of those are defined to only show
a diff when the merge result at the relevant paths differs from *both*
parents).
So, for separate, first-parent, and remerge styles of diff-merges, turn
off history simplification.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When this option is specified, we remerge all (two parent) merge commits
and diff the actual merge commit to the automatically created version,
in order to show how users removed conflict markers, resolved the
different conflict versions, and potentially added new changes outside
of conflict regions in order to resolve semantic merge problems (or,
possibly, just to hide other random changes).
This capability works by creating a temporary object directory and
marking it as the primary object store. This makes it so that any blobs
or trees created during the automatic merge are easily removable
afterwards by just deleting all objects from the temporary object
directory.
There are a few ways that this implementation is suboptimal:
* `log --remerge-diff` becomes slow, because the temporary object
directory can fill with many loose objects while running
* the log output can be muddied with misplaced "warning: cannot merge
binary files" messages, since ll-merge.c unconditionally writes those
messages to stderr while running instead of allowing callers to
manage them.
* important conflict and warning messages are simply dropped; thus for
conflicts like modify/delete or rename/rename or file/directory which
are not representable with content conflict markers, there may be no
way for a user of --remerge-diff to know that there had been a
conflict which was resolved (and which possibly motivated other
changes in the merge commit).
* when fixing the previous issue, note that some unimportant conflict
and warning messages might start being included. We should instead
make sure these remain dropped.
Subsequent commits will address these issues.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This fixes 19b2517f (diff-merges: move specific diff-index "-m"
handling to diff-index, 2021-05-21).
That commit disabled handling of all diff for merges options in
diff-index on an assumption that they are unused. However, it later
appeared that -c and --cc, even though undocumented and not being
covered by tests, happen to have had particular effect on diff-index
output.
Restore original -c/--cc options handling by diff-index.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit f5bfcc823b, which
made "git log -m" imply "--patch" by default. The logic was that
"-m", which makes diff generation for merges perform a diff against
each parent, has no use unless I am viewing the diff, so we could save
the user some typing by turning on display of the resulting diff
automatically. That wasn't expected to adversely affect scripts
because scripts would either be using a command like "git diff-tree"
that already emits diffs by default or would be combining -m with a
diff generation option such as --name-status. By saving typing for
interactive use without adversely affecting scripts in the wild, it
would be a pure improvement.
The problem is that although diff generation options are only relevant
for the displayed diff, a script author can imagine them affecting
path limiting. For example, I might run
git log -w --format=%H -- README
hoping to list commits that edited README, excluding whitespace-only
changes. In fact, a whitespace-only change is not TREESAME so the use
of -w here has no effect (since we don't apply these diff generation
flags to the diff_options struct rev_info::pruning used for this
purpose), but the documentation suggests that it should work
Suppose you specified foo as the <paths>. We shall call
commits that modify foo !TREESAME, and the rest TREESAME. (In
a diff filtered for foo, they look different and equal,
respectively.)
and a script author who has not tested whitespace-only changes
wouldn't notice.
Similarly, a script author could include
git log -m --first-parent --format=%H -- README
to filter the first-parent history for commits that modified README.
The -m is a no-op but it reflects the script author's intent. For
example, until 1e20a407fe (stash list: stop passing "-m" to "git
log", 2021-05-21), "git stash list" did this.
As a result, we can't safely change "-m" to imply "-p" without fear of
breaking such scripts. Restore the previous behavior.
Noticed because Rust's src/bootstrap/bootstrap.py made use of this
same construct: https://github.com/rust-lang/rust/pull/87513. That
script has been updated to omit the unnecessary "-m" option, but we
can expect other scripts in the wild to have similar expectations.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix long standing inconsistency between -c/--cc that do imply -p on
one side, and -m that did not imply -p on the other side.
Change corresponding test accordingly, as "log -m" output should now
match one from "log -m -p", rather than from just "log".
Change documentation accordingly.
NOTES:
After this patch
git log -m
produces diffs without need to provide -p as well, that improves both
consistency and usability. It gets even more useful if one sets
"log.diffMerges" configuration variable to "first-parent" to force -m
produce usual diff with respect to first parent only.
This patch, however, does not change behavior when specific diff
format is explicitly provided on the command-line, so that commands
like
git log -m --raw
git log -m --stat
are not affected, nor does it change commands where specific diff
format is active by default, such as:
git diff-tree -m
It's also worth to be noticed that exact historical semantics of -m is
still provided by --diff-merges=separate.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is refactoring change in preparation for the next commit that
will let -m imply -p.
The old name doesn't match the intention to let not only -c/-cc imply
-p, but also -m, that is not a "combined" format, so we rename the
flag accordingly.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move specific handling of "-m" for diff-index to diff-index.c, so
diff-merges is left to handle only diff for merges options.
Being a better design by itself, this is especially essential in
preparation for letting -m imply -p, as "diff-index -m" obviously
should not imply -p, as it's entirely unrelated.
To handle this, in addition to moving specific diff-index "-m" code
out of diff-merges, we introduce new
diff_merges_suppress_options_parsing()
and call it before generic options processing in cmd_diff_index().
This new diff_merges_suppress_options_parsing() could then be reused
and called before invocations of setup_revisions() for other commands
that don't need --diff-merges options, but that's outside of the scope
of these patch series.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
New log.diffMerges configuration variable sets the format that
--diff-merges=on will be using. The default is "separate".
t4013: add the following tests for log.diffMerges config:
* Test that wrong values are denied.
* Test that the value of log.diffMerges properly affects both
--diff-merges=on and -m.
t9902: fix completion tests for log.d* to match log.diffMerges.
Added documentation for log.diffMerges.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Let -m option (and --diff-merges=m) enable the default format instead
of "separate", to be able to tune it with log.diffMerges option.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Split set_diff_merges() into separate parsing and execution functions,
the former to be reused for parsing of configuration values later in
the patch series.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce the notion of default diff format for merges, and the option
"on" to select it. The default format is "separate" and can't yet
be changed, so effectively "on" is just a synonym for "separate"
for now. Add corresponding test to t4013.
This is in preparation for introducing log.diffMerges configuration
option that will let --diff-merges=on to be configured to any
supported format.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As we now have --diff-merges={m|c|cc}, add --diff-merges=1 as synonym
for --diff-merges=first-parent, to have shorter mnemonics for it as
well.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This adds --diff-merges={m|c|cc} values that match mnemonics of old
options, for those who are used to them.
Note that, say, --diff-meres=cc behaves differently than --cc, as the
latter implies -p and therefore enables diffs for all the commits,
while the former enables output of diffs for merge commits only.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
New options don't have any visible effect unless -p is either given or
implied, as unlike -c/-cc we don't imply -p with --diff-merges. To fix
this, this patch adds new functionality by letting new options enable
output of diffs for merge commits only.
Add 'merges_need_diff' field and set it whenever diff output for merges is
enabled by any of the new options.
Extend diff output logic accordingly, to output diffs for merges when
'merges_need_diff' is set even when no -p has been provided.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add 'combined_imply_patch' field and set it only for old --cc/-c
options, then imply -p if this flag is set instead of implying -p
whenever 'combined_merge' flag is set.
We don't want new --diff-merge options to imply -p, to make it
possible to enable output of diffs for merges independently from
non-merge commits. At the same time we want to preserve behavior of
old --c/-c/-m options and their interactions with --first-parent, to
stay backward-compatible.
This patch is first step in this direction: it separates old "--cc/-c
imply -p" logic from the rest of the options.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We first implement new options as exact synonyms for their original
counterparts, to get all the infrastructure right, and keep functional
improvements for later commits.
The following values are implemented:
--diff-merges= old equivalent
first|first-parent = --first-parent (only format implications)
sep|separate = -m
comb|combined = -c
dense| dense-combined = --cc
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
-c/--cc got precedence over -m only because of external logic where
corresponding flags are checked before that for -m. This is too
error-prone, so add code that explicitly makes these 3 options
mutually exclusive, so that the last option specified on the
command-line gets precedence.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To prepare introduction of new options some of which will be synonyms
to existing options, let every option handling code just call
corresponding function.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
After getting rid of 'ignore_merges' field, the diff_merges_init_revs()
function became empty. Get rid of it.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
'ignore_merges' was 3-way field that served two distinct purposes that
we now assign to 2 new independent flags: 'separate_merges', and
'explicit_diff_merges'.
'separate_merges' tells that we need to output diff format containing
separate diff for every parent (as opposed to 'combine_merges').
'explicit_diff_merges' tells that at least one of diff-merges options
has been explicitly specified on the command line, so no defaults
should apply.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Logically, -m, -c, --cc specify 3 different formats for representing
merge commits, yet -m doesn't in fact override -c or --cc, that makes
no sense.
Fix -m to properly override -c/--cc, and change the tests accordingly.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Do not set revs->diff when we encounter an option that needs it, as
it'd be impossible to undo later. Besides, some other options than
what we handle here set this flag as well, and we'd interfere with
them trying to clear this flag later.
Rather set revs->diff, if finally needed, in diff_merges_setup_revs().
As an additional bonus, this also makes our code shorter.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move logic that handles implying -p on -c/--cc from
log_setup_revisions_tweak() to diff_merges_setup_revs(), where it
belongs.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new field allows us to separate format of diff for merges from
'first_parent_only' flag which primary purpose is limiting history
traversal.
This change further localizes diff format selection logic into the
diff-merges.c file.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Call it where given functionality is needed instead of direct
checking/tweaking of diff merges related fields.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function sets all the relevant flags to disabled state, so that
no code that checks only one of them get it wrong.
Then we call this new function everywhere where diff merges output
suppression is needed.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For clarity, define public functions in the order they are called, to
make logic inter-dependencies easier to grok.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename diff_merges_default_to_enable() to
diff_merges_default_to_first_parent() to match its semantics.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The checks for first_parent_only don't in fact belong to this module,
as the primary purpose of this flag is history traversal limiting, so
get it out of this module and rename the
diff_merges_first_parent_defaults_to_enable()
to
diff_merges_default_to_enable()
to match new semantics.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use the same "diff_merges" prefix for all the diff merges function
names.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create separate diff-merges.c and diff-merges.h files, and move all
the code related to handling of diff merges there.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Elijah Newren
Sergey Organov
Jonathan Nieder