Re: [PATCH 1/1] rebase: deprecate --preserve-merges

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Phillip,

On Thu, 7 Mar 2019, Phillip Wood wrote:

> It's great to see this. Do we need the deprecation warning in both
> builtin/rebase.c and rebase--preserve-merges.sh? Won't that end up warning
> twice - maybe that's a good thing but if we go for only one I prefer the
> wording in rebase--preserve-merges.sh

Good point.

I also considered adding a warning to the todo list, in case the rebase is
run interactively, but that would have required way too many changes in
the test suite (the test cases using `FAKE_LINES` select lines from the
todo list based on their line number, not their content, which does not
play well with inserting 3 lines with a warning at the beginning of the
todo list).

Ciao,
Dscho

> 
> Best Wishes
> 
> Phillip
> 
> On 07/03/2019 10:00, Johannes Schindelin via GitGitGadget wrote:
> > From: Johannes Schindelin <johannes.schindelin@gmx.de>
> > 
> > We have something much better now: --rebase-merges (which is a
> > complete re-design --preserve-merges, with a lot of issues fixed such as
> > the inability to reorder commits with --preserve-merges).
> > 
> > Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> > ---
> >   Documentation/config/branch.txt |  6 +++---
> >   Documentation/config/pull.txt   |  6 +++---
> >   Documentation/git-rebase.txt    | 23 ++++++++++++-----------
> >   builtin/rebase.c                |  8 ++++++--
> >   git-rebase--preserve-merges.sh  |  2 ++
> >   5 files changed, 26 insertions(+), 19 deletions(-)
> > 
> > diff --git a/Documentation/config/branch.txt
> > b/Documentation/config/branch.txt
> > index 019d60ede2..8f4b3faadd 100644
> > --- a/Documentation/config/branch.txt
> > +++ b/Documentation/config/branch.txt
> > @@ -85,9 +85,9 @@ When `merges`, pass the `--rebase-merges` option to 'git
> > rebase'
> >   so that the local merge commits are included in the rebase (see
> >   linkgit:git-rebase[1] for details).
> >   +
> > -When preserve, also pass `--preserve-merges` along to 'git rebase'
> > -so that locally committed merge commits will not be flattened
> > -by running 'git pull'.
> > +When `preserve` (deprecated in favor of `merges`), also pass
> > +`--preserve-merges` along to 'git rebase' so that locally committed merge
> > +commits will not be flattened by running 'git pull'.
> >   +
> >   When the value is `interactive`, the rebase is run in interactive mode.
> >   +
> > diff --git a/Documentation/config/pull.txt b/Documentation/config/pull.txt
> > index bb23a9947d..b87cab31b3 100644
> > --- a/Documentation/config/pull.txt
> > +++ b/Documentation/config/pull.txt
> > @@ -18,9 +18,9 @@ When `merges`, pass the `--rebase-merges` option to 'git
> > rebase'
> >   so that the local merge commits are included in the rebase (see
> >   linkgit:git-rebase[1] for details).
> >   +
> > -When preserve, also pass `--preserve-merges` along to 'git rebase'
> > -so that locally committed merge commits will not be flattened
> > -by running 'git pull'.
> > +When `preserve` (deprecated in favor of `merges`), also pass
> > +`--preserve-merges` along to 'git rebase' so that locally committed merge
> > +commits will not be flattened by running 'git pull'.
> >   +
> >   When the value is `interactive`, the rebase is run in interactive mode.
> >   +
> > diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
> > index 5629ba4c5d..89202dbb93 100644
> > --- a/Documentation/git-rebase.txt
> > +++ b/Documentation/git-rebase.txt
> > @@ -415,9 +415,9 @@ i.e. commits that would be excluded by
> > gitlink:git-log[1]'s
> >   the `rebase-cousins` mode is turned on, such commits are instead rebased
> >   onto `<upstream>` (or `<onto>`, if specified).
> >   +
> > -The `--rebase-merges` mode is similar in spirit to `--preserve-merges`, but
> > -in contrast to that option works well in interactive rebases: commits can
> > be
> > -reordered, inserted and dropped at will.
> > +The `--rebase-merges` mode is similar in spirit to the deprecated
> > +`--preserve-merges`, but in contrast to that option works well in
> > interactive
> > +rebases: commits can be reordered, inserted and dropped at will.
> >   +
> >   It is currently only possible to recreate the merge commits using the
> >   `recursive` merge strategy; Different merge strategies can be used only
> >   via
> > @@ -427,9 +427,10 @@ See also REBASING MERGES and INCOMPATIBLE OPTIONS
> > below.
> >   
> >   -p::
> >   --preserve-merges::
> > -	Recreate merge commits instead of flattening the history by replaying
> > -	commits a merge commit introduces. Merge conflict resolutions or
> > manual
> > -	amendments to merge commits are not preserved.
> > +	[DEPRECATED: use --rebase-merges instead] Recreate merge commits
> > +	instead of flattening the history by replaying commits a merge commit
> > +	introduces. Merge conflict resolutions or manual amendments to merge
> > +	commits are not preserved.
> >   +
> >   This uses the `--interactive` machinery internally, but combining it
> >   with the `--interactive` option explicitly is generally not a good
> > @@ -1020,11 +1021,11 @@ merge cmake
> >   
> >   BUGS
> >   ----
> > -The todo list presented by `--preserve-merges --interactive` does not
> > -represent the topology of the revision graph.  Editing commits and
> > -rewording their commit messages should work fine, but attempts to
> > -reorder commits tend to produce counterintuitive results. Use
> > -`--rebase-merges` in such scenarios instead.
> > +The todo list presented by the deprecated `--preserve-merges --interactive`
> > +does not represent the topology of the revision graph (use
> > `--rebase-merges`
> > +instead).  Editing commits and rewording their commit messages should work
> > +fine, but attempts to reorder commits tend to produce counterintuitive
> > results.
> > +Use `--rebase-merges` in such scenarios instead.
> >   
> >   For example, an attempt to rearrange
> >   ------------
> > diff --git a/builtin/rebase.c b/builtin/rebase.c
> > index 7c7bc13e91..c5f5edf321 100644
> > --- a/builtin/rebase.c
> > +++ b/builtin/rebase.c
> > @@ -1092,8 +1092,8 @@ int cmd_rebase(int argc, const char **argv, const char
> > *prefix)
> >      PARSE_OPT_NOARG | PARSE_OPT_NONEG,
> >      parse_opt_interactive },
> >   		OPT_SET_INT('p', "preserve-merges", &options.type,
> > -			    N_("try to recreate merges instead of ignoring "
> > -			       "them"), REBASE_PRESERVE_MERGES),
> > +			    N_("(DEPRECATED) try to recreate merges instead of
> > "
> > +			       "ignoring them"), REBASE_PRESERVE_MERGES),
> >     OPT_BOOL(0, "rerere-autoupdate",
> >       &options.allow_rerere_autoupdate,
> >       N_("allow rerere to update index with resolved "
> > @@ -1204,6 +1204,10 @@ int cmd_rebase(int argc, const char **argv, const
> > char *prefix)
> >     usage_with_options(builtin_rebase_usage,
> >          builtin_rebase_options);
> >   +	if (options.type == REBASE_PRESERVE_MERGES)
> > +		warning(_("--preserve-merges is deprecated in favor of "
> > +			  "--rebase-merges"));
> > +
> >    if (action != NO_ACTION && !in_progress)
> >    	die(_("No rebase in progress?"));
> >   	setenv(GIT_REFLOG_ACTION_ENVIRONMENT, "rebase", 0);
> > diff --git a/git-rebase--preserve-merges.sh b/git-rebase--preserve-merges.sh
> > index afbb65765d..eab2e40dc6 100644
> > --- a/git-rebase--preserve-merges.sh
> > +++ b/git-rebase--preserve-merges.sh
> > @@ -105,6 +105,8 @@ warn () {
> >   	printf '%s\n' "$*" >&2
> >   }
> >   
> > +warn "git rebase --preserve-merges is deprecated. Use --rebase-merges
> > instead."
> > +
> >   # Output the commit message for the specified commit.
> >   commit_message () {
> >    git cat-file commit "$1" | sed "1,/^$/d"
> > 
>