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git/builtin/rebase--helper.c

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rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
#include "builtin.h"
#include "cache.h"
config: don't include config.h by default Stop including config.h by default in cache.h. Instead only include config.h in those files which require use of the config system. Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-14 20:07:36 +02:00
#include "config.h"
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
#include "parse-options.h"
#include "sequencer.h"
static const char * const builtin_rebase_helper_usage[] = {
N_("git rebase--helper [<options>]"),
NULL
};
int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
{
struct replay_opts opts = REPLAY_OPTS_INIT;
rebase-helper --make-script: introduce a flag to rebase merges The sequencer just learned new commands intended to recreate branch structure (similar in spirit to --preserve-merges, but with a substantially less-broken design). Let's allow the rebase--helper to generate todo lists making use of these commands, triggered by the new --rebase-merges option. For a commit topology like this (where the HEAD points to C): - A - B - C \ / D the generated todo list would look like this: # branch D pick 0123 A label branch-point pick 1234 D label D reset branch-point pick 2345 B merge -C 3456 D # C To keep things simple, we first only implement support for merge commits with exactly two parents, leaving support for octopus merges to a later patch series. All merge-rebasing todo lists start with a hard-coded `label onto` line. This makes it convenient to refer later on to the revision onto which everything is rebased, e.g. as starting point for branches other than the very first one. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:03 +02:00
unsigned flags = 0, keep_empty = 0, rebase_merges = 0;
rebase -i: introduce --rebase-merges=[no-]rebase-cousins When running `git rebase --rebase-merges` non-interactively with an ancestor of HEAD as <upstream> (or leaving the todo list unmodified), we would ideally recreate the exact same commits as before the rebase. However, if there are commits in the commit range <upstream>.. that do not have <upstream> as direct ancestor (i.e. if `git log <upstream>..` would show commits that are omitted by `git log --ancestry-path <upstream>..`), this is currently not the case: we would turn them into commits that have <upstream> as direct ancestor. Let's illustrate that with a diagram: C / \ A - B - E - F \ / D Currently, after running `git rebase -i --rebase-merges B`, the new branch structure would be (pay particular attention to the commit `D`): --- C' -- / \ A - B ------ E' - F' \ / D' This is not really preserving the branch topology from before! The reason is that the commit `D` does not have `B` as ancestor, and therefore it gets rebased onto `B`. This is unintuitive behavior. Even worse, when recreating branch structure, most use cases would appear to want cousins *not* to be rebased onto the new base commit. For example, Git for Windows (the heaviest user of the Git garden shears, which served as the blueprint for --rebase-merges) frequently merges branches from `next` early, and these branches certainly do *not* want to be rebased. In the example above, the desired outcome would look like this: --- C' -- / \ A - B ------ E' - F' \ / -- D' -- Let's introduce the term "cousins" for such commits ("D" in the example), and let's not rebase them by default. For hypothetical use cases where cousins *do* need to be rebased, `git rebase --rebase=merges=rebase-cousins` needs to be used. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:40 +02:00
int abbreviate_commands = 0, rebase_cousins = -1;
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
enum {
rebase -i: replace reference to sha1 with oid Since we are trying to abstract the hash function name elsewhere in the code base, lets use OID instead of SHA-1 in the rebase--helper too. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:31 +01:00
CONTINUE = 1, ABORT, MAKE_SCRIPT, SHORTEN_OIDS, EXPAND_OIDS,
rebase -i -x: add exec commands via the rebase--helper Recent work on `git-rebase--interactive` aims to convert shell code to C. Even if this is most likely not a big performance enhancement, let's convert it too since a coming change to abbreviate command names requires it to be updated. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:33 +01:00
CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS, REARRANGE_SQUASH,
ADD_EXEC
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
} command = 0;
struct option options[] = {
OPT_BOOL(0, "ff", &opts.allow_ff, N_("allow fast-forward")),
rebase -i: generate the script via rebase--helper The first step of an interactive rebase is to generate the so-called "todo script", to be stored in the state directory as "git-rebase-todo" and to be edited by the user. Originally, we adjusted the output of `git log <options>` using a simple sed script. Over the course of the years, the code became more complicated. We now use shell scripting to edit the output of `git log` conditionally, depending whether to keep "empty" commits (i.e. commits that do not change any files). On platforms where shell scripting is not native, this can be a serious drag. And it opens the door for incompatibilities between platforms when it comes to shell scripting or to Unix-y commands. Let's just re-implement the todo script generation in plain C, using the revision machinery directly. This is substantially faster, improving the speed relative to the shell script version of the interactive rebase from 2x to 3x on Windows. Note that the rearrange_squash() function in git-rebase--interactive relied on the fact that we set the "format" variable to the config setting rebase.instructionFormat. Relying on a side effect like this is no good, hence we explicitly perform that assignment (possibly again) in rearrange_squash(). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:44:58 +02:00
OPT_BOOL(0, "keep-empty", &keep_empty, N_("keep empty commits")),
rebase: add --allow-empty-message option This option allows commits with empty commit messages to be rebased, matching the same option in git-commit and git-cherry-pick. While empty log messages are frowned upon, sometimes one finds them in older repositories (e.g. translated from another VCS [0]), or have other reasons for desiring them. The option is available in git-commit and git-cherry-pick, so it is natural to make other git tools play nicely with them. Adding this as an option allows the default to be "give the user a chance to fix", while not interrupting the user's workflow otherwise [1]. [0]: https://stackoverflow.com/q/8542304 [1]: https://public-inbox.org/git/7vd33afqjh.fsf@alter.siamese.dyndns.org/ To implement this, add a new --allow-empty-message flag. Then propagate it to all calls of 'git commit', 'git cherry-pick', and 'git rebase--helper' within the rebase scripts. Signed-off-by: Genki Sky <sky@genki.is> Reviewed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-04 21:08:13 +01:00
OPT_BOOL(0, "allow-empty-message", &opts.allow_empty_message,
N_("allow commits with empty messages")),
rebase-helper --make-script: introduce a flag to rebase merges The sequencer just learned new commands intended to recreate branch structure (similar in spirit to --preserve-merges, but with a substantially less-broken design). Let's allow the rebase--helper to generate todo lists making use of these commands, triggered by the new --rebase-merges option. For a commit topology like this (where the HEAD points to C): - A - B - C \ / D the generated todo list would look like this: # branch D pick 0123 A label branch-point pick 1234 D label D reset branch-point pick 2345 B merge -C 3456 D # C To keep things simple, we first only implement support for merge commits with exactly two parents, leaving support for octopus merges to a later patch series. All merge-rebasing todo lists start with a hard-coded `label onto` line. This makes it convenient to refer later on to the revision onto which everything is rebased, e.g. as starting point for branches other than the very first one. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:03 +02:00
OPT_BOOL(0, "rebase-merges", &rebase_merges, N_("rebase merge commits")),
rebase -i: introduce --rebase-merges=[no-]rebase-cousins When running `git rebase --rebase-merges` non-interactively with an ancestor of HEAD as <upstream> (or leaving the todo list unmodified), we would ideally recreate the exact same commits as before the rebase. However, if there are commits in the commit range <upstream>.. that do not have <upstream> as direct ancestor (i.e. if `git log <upstream>..` would show commits that are omitted by `git log --ancestry-path <upstream>..`), this is currently not the case: we would turn them into commits that have <upstream> as direct ancestor. Let's illustrate that with a diagram: C / \ A - B - E - F \ / D Currently, after running `git rebase -i --rebase-merges B`, the new branch structure would be (pay particular attention to the commit `D`): --- C' -- / \ A - B ------ E' - F' \ / D' This is not really preserving the branch topology from before! The reason is that the commit `D` does not have `B` as ancestor, and therefore it gets rebased onto `B`. This is unintuitive behavior. Even worse, when recreating branch structure, most use cases would appear to want cousins *not* to be rebased onto the new base commit. For example, Git for Windows (the heaviest user of the Git garden shears, which served as the blueprint for --rebase-merges) frequently merges branches from `next` early, and these branches certainly do *not* want to be rebased. In the example above, the desired outcome would look like this: --- C' -- / \ A - B ------ E' - F' \ / -- D' -- Let's introduce the term "cousins" for such commits ("D" in the example), and let's not rebase them by default. For hypothetical use cases where cousins *do* need to be rebased, `git rebase --rebase=merges=rebase-cousins` needs to be used. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:40 +02:00
OPT_BOOL(0, "rebase-cousins", &rebase_cousins,
N_("keep original branch points of cousins")),
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
CONTINUE),
OPT_CMDMODE(0, "abort", &command, N_("abort rebase"),
ABORT),
rebase -i: generate the script via rebase--helper The first step of an interactive rebase is to generate the so-called "todo script", to be stored in the state directory as "git-rebase-todo" and to be edited by the user. Originally, we adjusted the output of `git log <options>` using a simple sed script. Over the course of the years, the code became more complicated. We now use shell scripting to edit the output of `git log` conditionally, depending whether to keep "empty" commits (i.e. commits that do not change any files). On platforms where shell scripting is not native, this can be a serious drag. And it opens the door for incompatibilities between platforms when it comes to shell scripting or to Unix-y commands. Let's just re-implement the todo script generation in plain C, using the revision machinery directly. This is substantially faster, improving the speed relative to the shell script version of the interactive rebase from 2x to 3x on Windows. Note that the rearrange_squash() function in git-rebase--interactive relied on the fact that we set the "format" variable to the config setting rebase.instructionFormat. Relying on a side effect like this is no good, hence we explicitly perform that assignment (possibly again) in rearrange_squash(). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:44:58 +02:00
OPT_CMDMODE(0, "make-script", &command,
N_("make rebase script"), MAKE_SCRIPT),
rebase -i: also expand/collapse the SHA-1s via the rebase--helper This is crucial to improve performance on Windows, as the speed is now mostly dominated by the SHA-1 transformation (because it spawns a new rev-parse process for *every* line, and spawning processes is pretty slow from Git for Windows' MSYS2 Bash). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:11 +02:00
OPT_CMDMODE(0, "shorten-ids", &command,
rebase -i: replace reference to sha1 with oid Since we are trying to abstract the hash function name elsewhere in the code base, lets use OID instead of SHA-1 in the rebase--helper too. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:31 +01:00
N_("shorten commit ids in the todo list"), SHORTEN_OIDS),
rebase -i: also expand/collapse the SHA-1s via the rebase--helper This is crucial to improve performance on Windows, as the speed is now mostly dominated by the SHA-1 transformation (because it spawns a new rev-parse process for *every* line, and spawning processes is pretty slow from Git for Windows' MSYS2 Bash). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:11 +02:00
OPT_CMDMODE(0, "expand-ids", &command,
rebase -i: replace reference to sha1 with oid Since we are trying to abstract the hash function name elsewhere in the code base, lets use OID instead of SHA-1 in the rebase--helper too. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:31 +01:00
N_("expand commit ids in the todo list"), EXPAND_OIDS),
rebase -i: check for missing commits in the rebase--helper In particular on Windows, where shell scripts are even more expensive than on MacOSX or Linux, it makes sense to move a loop that forks Git at least once for every line in the todo list into a builtin. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:21 +02:00
OPT_CMDMODE(0, "check-todo-list", &command,
N_("check the todo list"), CHECK_TODO_LIST),
rebase -i: skip unnecessary picks using the rebase--helper In particular on Windows, where shell scripts are even more expensive than on MacOSX or Linux, it makes sense to move a loop that forks Git at least once for every line in the todo list into a builtin. Note: The original code did not try to skip unnecessary picks of root commits but punts instead (probably --root was not considered common enough of a use case to bother optimizing). We do the same, for now. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:25 +02:00
OPT_CMDMODE(0, "skip-unnecessary-picks", &command,
N_("skip unnecessary picks"), SKIP_UNNECESSARY_PICKS),
rebase -i: rearrange fixup/squash lines using the rebase--helper This operation has quadratic complexity, which is especially painful on Windows, where shell scripts are *already* slow (mainly due to the overhead of the POSIX emulation layer). Let's reimplement this with linear complexity (using a hash map to match the commits' subject lines) for the common case; Sadly, the fixup/squash feature's design neglected performance considerations, allowing arbitrary prefixes (read: `fixup! hell` will match the commit subject `hello world`), which means that we are stuck with quadratic performance in the worst case. The reimplemented logic also happens to fix a bug where commented-out lines (representing empty patches) were dropped by the previous code. While at it, clarify how the fixup/squash feature works in `git rebase -i`'s man page. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:31 +02:00
OPT_CMDMODE(0, "rearrange-squash", &command,
N_("rearrange fixup/squash lines"), REARRANGE_SQUASH),
rebase -i -x: add exec commands via the rebase--helper Recent work on `git-rebase--interactive` aims to convert shell code to C. Even if this is most likely not a big performance enhancement, let's convert it too since a coming change to abbreviate command names requires it to be updated. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:33 +01:00
OPT_CMDMODE(0, "add-exec-commands", &command,
N_("insert exec commands in todo list"), ADD_EXEC),
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
OPT_END()
};
sequencer: improve config handling The previous config handling relied on global variables, called git_default_config() even when the key had already been handled by git_sequencer_config() and did not initialize the diff configuration variables. Improve this by: i) loading the default values for message cleanup and gpg signing of commits into struct replay_opts; ii) restructuring the code to return immediately once a key is handled; and iii) calling git_diff_basic_config(). Note that unfortunately it is not possible to return early if the key is handled by git_gpg_config() as it does not indicate to the caller if the key has been handled or not. The sequencer should probably have been calling git_diff_basic_config() before as it creates a patch when there are conflicts. The shell version uses 'diff-tree' to create the patch so calling git_diff_basic_config() should match that. Although 'git commit' calls git_diff_ui_config() I don't think the output of print_commit_summary() is affected by anything that is loaded by that as print_commit_summary() always turns on rename detection so would ignore the value in the user's configuration anyway. The other values loaded by git_diff_ui_config() are about the formatting of patches so are not relevant to print_commit_summary(). Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-13 12:46:21 +01:00
sequencer_init_config(&opts);
rebase -i: learn to abbreviate command names `git rebase -i` already know how to interpret single-letter command names. Teach it to generate the todo list with these same abbreviated names. Based-on-patch-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:34 +01:00
git_config_get_bool("rebase.abbreviatecommands", &abbreviate_commands);
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
opts.action = REPLAY_INTERACTIVE_REBASE;
opts.allow_ff = 1;
opts.allow_empty = 1;
argc = parse_options(argc, argv, NULL, options,
builtin_rebase_helper_usage, PARSE_OPT_KEEP_ARGV0);
rebase -i: update functions to use a flags parameter Update functions used in the rebase--helper so that they take a generic 'flags' parameter instead of a growing list of options. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:32 +01:00
flags |= keep_empty ? TODO_LIST_KEEP_EMPTY : 0;
rebase -i: learn to abbreviate command names `git rebase -i` already know how to interpret single-letter command names. Teach it to generate the todo list with these same abbreviated names. Based-on-patch-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:34 +01:00
flags |= abbreviate_commands ? TODO_LIST_ABBREVIATE_CMDS : 0;
rebase-helper --make-script: introduce a flag to rebase merges The sequencer just learned new commands intended to recreate branch structure (similar in spirit to --preserve-merges, but with a substantially less-broken design). Let's allow the rebase--helper to generate todo lists making use of these commands, triggered by the new --rebase-merges option. For a commit topology like this (where the HEAD points to C): - A - B - C \ / D the generated todo list would look like this: # branch D pick 0123 A label branch-point pick 1234 D label D reset branch-point pick 2345 B merge -C 3456 D # C To keep things simple, we first only implement support for merge commits with exactly two parents, leaving support for octopus merges to a later patch series. All merge-rebasing todo lists start with a hard-coded `label onto` line. This makes it convenient to refer later on to the revision onto which everything is rebased, e.g. as starting point for branches other than the very first one. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:03 +02:00
flags |= rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
rebase -i: introduce --rebase-merges=[no-]rebase-cousins When running `git rebase --rebase-merges` non-interactively with an ancestor of HEAD as <upstream> (or leaving the todo list unmodified), we would ideally recreate the exact same commits as before the rebase. However, if there are commits in the commit range <upstream>.. that do not have <upstream> as direct ancestor (i.e. if `git log <upstream>..` would show commits that are omitted by `git log --ancestry-path <upstream>..`), this is currently not the case: we would turn them into commits that have <upstream> as direct ancestor. Let's illustrate that with a diagram: C / \ A - B - E - F \ / D Currently, after running `git rebase -i --rebase-merges B`, the new branch structure would be (pay particular attention to the commit `D`): --- C' -- / \ A - B ------ E' - F' \ / D' This is not really preserving the branch topology from before! The reason is that the commit `D` does not have `B` as ancestor, and therefore it gets rebased onto `B`. This is unintuitive behavior. Even worse, when recreating branch structure, most use cases would appear to want cousins *not* to be rebased onto the new base commit. For example, Git for Windows (the heaviest user of the Git garden shears, which served as the blueprint for --rebase-merges) frequently merges branches from `next` early, and these branches certainly do *not* want to be rebased. In the example above, the desired outcome would look like this: --- C' -- / \ A - B ------ E' - F' \ / -- D' -- Let's introduce the term "cousins" for such commits ("D" in the example), and let's not rebase them by default. For hypothetical use cases where cousins *do* need to be rebased, `git rebase --rebase=merges=rebase-cousins` needs to be used. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:40 +02:00
flags |= rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
rebase -i: update functions to use a flags parameter Update functions used in the rebase--helper so that they take a generic 'flags' parameter instead of a growing list of options. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:32 +01:00
flags |= command == SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
rebase -i: introduce --rebase-merges=[no-]rebase-cousins When running `git rebase --rebase-merges` non-interactively with an ancestor of HEAD as <upstream> (or leaving the todo list unmodified), we would ideally recreate the exact same commits as before the rebase. However, if there are commits in the commit range <upstream>.. that do not have <upstream> as direct ancestor (i.e. if `git log <upstream>..` would show commits that are omitted by `git log --ancestry-path <upstream>..`), this is currently not the case: we would turn them into commits that have <upstream> as direct ancestor. Let's illustrate that with a diagram: C / \ A - B - E - F \ / D Currently, after running `git rebase -i --rebase-merges B`, the new branch structure would be (pay particular attention to the commit `D`): --- C' -- / \ A - B ------ E' - F' \ / D' This is not really preserving the branch topology from before! The reason is that the commit `D` does not have `B` as ancestor, and therefore it gets rebased onto `B`. This is unintuitive behavior. Even worse, when recreating branch structure, most use cases would appear to want cousins *not* to be rebased onto the new base commit. For example, Git for Windows (the heaviest user of the Git garden shears, which served as the blueprint for --rebase-merges) frequently merges branches from `next` early, and these branches certainly do *not* want to be rebased. In the example above, the desired outcome would look like this: --- C' -- / \ A - B ------ E' - F' \ / -- D' -- Let's introduce the term "cousins" for such commits ("D" in the example), and let's not rebase them by default. For hypothetical use cases where cousins *do* need to be rebased, `git rebase --rebase=merges=rebase-cousins` needs to be used. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-25 14:29:40 +02:00
if (rebase_cousins >= 0 && !rebase_merges)
warning(_("--[no-]rebase-cousins has no effect without "
"--rebase-merges"));
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
if (command == CONTINUE && argc == 1)
return !!sequencer_continue(&opts);
if (command == ABORT && argc == 1)
return !!sequencer_remove_state(&opts);
rebase -i: generate the script via rebase--helper The first step of an interactive rebase is to generate the so-called "todo script", to be stored in the state directory as "git-rebase-todo" and to be edited by the user. Originally, we adjusted the output of `git log <options>` using a simple sed script. Over the course of the years, the code became more complicated. We now use shell scripting to edit the output of `git log` conditionally, depending whether to keep "empty" commits (i.e. commits that do not change any files). On platforms where shell scripting is not native, this can be a serious drag. And it opens the door for incompatibilities between platforms when it comes to shell scripting or to Unix-y commands. Let's just re-implement the todo script generation in plain C, using the revision machinery directly. This is substantially faster, improving the speed relative to the shell script version of the interactive rebase from 2x to 3x on Windows. Note that the rearrange_squash() function in git-rebase--interactive relied on the fact that we set the "format" variable to the config setting rebase.instructionFormat. Relying on a side effect like this is no good, hence we explicitly perform that assignment (possibly again) in rearrange_squash(). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:44:58 +02:00
if (command == MAKE_SCRIPT && argc > 1)
rebase -i: update functions to use a flags parameter Update functions used in the rebase--helper so that they take a generic 'flags' parameter instead of a growing list of options. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:32 +01:00
return !!sequencer_make_script(stdout, argc, argv, flags);
if ((command == SHORTEN_OIDS || command == EXPAND_OIDS) && argc == 1)
return !!transform_todos(flags);
rebase -i: check for missing commits in the rebase--helper In particular on Windows, where shell scripts are even more expensive than on MacOSX or Linux, it makes sense to move a loop that forks Git at least once for every line in the todo list into a builtin. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:21 +02:00
if (command == CHECK_TODO_LIST && argc == 1)
return !!check_todo_list();
rebase -i: skip unnecessary picks using the rebase--helper In particular on Windows, where shell scripts are even more expensive than on MacOSX or Linux, it makes sense to move a loop that forks Git at least once for every line in the todo list into a builtin. Note: The original code did not try to skip unnecessary picks of root commits but punts instead (probably --root was not considered common enough of a use case to bother optimizing). We do the same, for now. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:25 +02:00
if (command == SKIP_UNNECESSARY_PICKS && argc == 1)
return !!skip_unnecessary_picks();
rebase -i: rearrange fixup/squash lines using the rebase--helper This operation has quadratic complexity, which is especially painful on Windows, where shell scripts are *already* slow (mainly due to the overhead of the POSIX emulation layer). Let's reimplement this with linear complexity (using a hash map to match the commits' subject lines) for the common case; Sadly, the fixup/squash feature's design neglected performance considerations, allowing arbitrary prefixes (read: `fixup! hell` will match the commit subject `hello world`), which means that we are stuck with quadratic performance in the worst case. The reimplemented logic also happens to fix a bug where commented-out lines (representing empty patches) were dropped by the previous code. While at it, clarify how the fixup/squash feature works in `git rebase -i`'s man page. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-14 16:45:31 +02:00
if (command == REARRANGE_SQUASH && argc == 1)
return !!rearrange_squash();
rebase -i -x: add exec commands via the rebase--helper Recent work on `git-rebase--interactive` aims to convert shell code to C. Even if this is most likely not a big performance enhancement, let's convert it too since a coming change to abbreviate command names requires it to be updated. Signed-off-by: Liam Beguin <liambeguin@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05 18:52:33 +01:00
if (command == ADD_EXEC && argc == 2)
return !!sequencer_add_exec_commands(argv[1]);
rebase--helper: add a builtin helper for interactive rebases Git's interactive rebase is still implemented as a shell script, despite its complexity. This implies that it suffers from the portability point of view, from lack of expressibility, and of course also from performance. The latter issue is particularly serious on Windows, where we pay a hefty price for relying so much on POSIX. Unfortunately, being such a huge shell script also means that we missed the train when it would have been relatively easy to port it to C, and instead piled feature upon feature onto that poor script that originally never intended to be more than a slightly pimped cherry-pick in a loop. To open the road toward better performance (in addition to all the other benefits of C over shell scripts), let's just start *somewhere*. The approach taken here is to add a builtin helper that at first intends to take care of the parts of the interactive rebase that are most affected by the performance penalties mentioned above. In particular, after we spent all those efforts on preparing the sequencer to process rebase -i's git-rebase-todo scripts, we implement the `git rebase -i --continue` functionality as a new builtin, git-rebase--helper. Once that is in place, we can work gradually on tackling the rest of the technical debt. Note that the rebase--helper needs to learn about the transient --ff/--no-ff options of git-rebase, as the corresponding flag is not persisted to, and re-read from, the state directory. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-09 23:23:06 +01:00
usage_with_options(builtin_rebase_helper_usage, options);
}
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