On Tue, Nov 1, 2022 at 1:55 AM Kyle Zhao via GitGitGadget
<gitgitgadget@xxxxxxxxx> wrote:
>
> From: Kyle Zhao <kylezhao@xxxxxxxxxxx>
>
> The previous change add "--merge-base" option in order to allow users to
s/add/added/ ?
> specify merge-base for the merge. But it doesn't compatible well with
> --stdin, because multiple batched merges can only have the same specified
> base.
"it doesn't compatible well" doesn't parse for me.
> This patch allows users to pass --merge-base option into the input line,
> such as:
Quoting from Documentation/SubmittingPatches:
"""
Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
to do frotz", as if you are giving orders to the codebase to change
its behavior.
"""
>
> printf "--merge-base=<b3> <b1> <b2>" | git merge-tree --stdin
>
> This does a merge of b1 and b2, and uses b3 as the merge-base.
Perhaps something like:
"""
The previous commit added a `--merge-base` option in order to allow
using a specified merge-base for the merge. Extend the input accepted
by `--stdin` to also allow a specified merge-base with each merge
requested. For example:
printf "--merge-base=<b3> <b1> <b2>" | git merge-tree --stdin
does a merge of b1 and b2, and uses b3 as the merge-base.
"""
However, I'm a bit curious about using `--merge-base=` on the input
line as opposed to just using a simpler marker; something like
printf "<b3> -- <b1> <b2>" | git merge-tree --stdin
(which follows a precedent set by git-merge-recursive). Your version
is a bit more self-documenting, but what if we want to allow users to
specify multiple merge bases in the future (for use in passing to
merge_incore_recursive())? Is it annoying to need to prefix each one?
> Signed-off-by: Kyle Zhao <kylezhao@xxxxxxxxxxx>
> ---
> Documentation/git-merge-tree.txt | 3 ++-
> builtin/merge-tree.c | 22 ++++++++++++++++++++--
> t/t4301-merge-tree-write-tree.sh | 21 +++++++++++++++++++++
> 3 files changed, 43 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/git-merge-tree.txt b/Documentation/git-merge-tree.txt
> index d9dacb2ce54..be6a11bbaec 100644
> --- a/Documentation/git-merge-tree.txt
> +++ b/Documentation/git-merge-tree.txt
> @@ -66,7 +66,8 @@ OPTIONS
>
> --merge-base=<commit>::
> Instead of finding the merge-bases for <branch1> and <branch2>,
> - specify a merge-base for the merge.
> + specify a merge-base for the merge. When --stdin is passed, this
> + option should be passed into the input line.
I'm not sure "passed into the input line" will be clear to readers.
Perhaps we want to have --stdin documented (looks like I forgot to do
that in my series; oops), mentioning the input format.
> [[OUTPUT]]
> OUTPUT
> diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
> index f402b807c0f..7a8049e7b0c 100644
> --- a/builtin/merge-tree.c
> +++ b/builtin/merge-tree.c
> @@ -551,16 +551,34 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
>
> if (o.mode == MODE_TRIVIAL)
> die(_("--trivial-merge is incompatible with all other options"));
> + if (merge_base)
> + die(_("--merge-base should be passed into the input line"));
If we change the input as noted above, the wording here may need to change too.
> line_termination = '\0';
> while (strbuf_getline_lf(&buf, stdin) != EOF) {
> struct strbuf **split;
> int result;
> + const char *input_merge_base = NULL;
> + const char *arg;
>
> split = strbuf_split(&buf, ' ');
> - if (!split[0] || !split[1] || split[2])
> + if (!split[0] || !split[1])
> die(_("malformed input line: '%s'."), buf.buf);
> strbuf_rtrim(split[0]);
> - result = real_merge(&o, merge_base, split[0]->buf, split[1]->buf, prefix);
> +
> + /* parse --merge-base=<commit> option */
> + arg = split[0]->buf;
> + if (skip_prefix(arg, "--merge-base=", &arg))
> + input_merge_base = arg;
> +
> + if (input_merge_base && split[2] && !split[3]) {
> + strbuf_rtrim(split[1]);
> + result = real_merge(&o, input_merge_base, split[1]->buf, split[2]->buf, prefix);
> + } else if (!input_merge_base && !split[2]) {
> + result = real_merge(&o, NULL, split[0]->buf, split[1]->buf, prefix);
> + } else {
> + die(_("malformed input line: '%s'."), buf.buf);
> + }
> +
> if (result < 0)
> die(_("merging cannot continue; got unclean result of %d"), result);
> strbuf_list_free(split);
> diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
> index 5b0073d3dcd..aec2c00b91f 100755
> --- a/t/t4301-merge-tree-write-tree.sh
> +++ b/t/t4301-merge-tree-write-tree.sh
> @@ -860,6 +860,13 @@ test_expect_success '--stdin with both a successful and a conflicted merge' '
> test_cmp expect actual
> '
>
> +
> +test_expect_success '--merge-base is incompatible with --stdin' '
> + test_must_fail git merge-tree --merge-base=side1 --stdin 2>expect &&
> +
> + grep "^fatal: --merge-base should be passed into the input line" expect
> +'
Yeah, most merge-tree options are for controlling the output, and as
such they are not incompatible with --stdin. This option is, so it
makes sense you need a special check for it. Looks good.
> +
> # specify merge-base as parent of branch2
> # git merge-tree --write-tree --merge-base=c2 c1 c3
> # Commit c1: add file1
> @@ -890,4 +897,18 @@ test_expect_success 'specify merge-base as parent of branch2' '
> )
> '
>
> +test_expect_success '--stdin with both a normal merge and a merge-base specified merge' '
> + cd base-b2-p &&
> + printf "c1 c3\n--merge-base=c2 c1 c3" | git merge-tree --stdin >actual &&
> +
> + printf "1\0" >expect &&
> + git merge-tree --write-tree -z c1 c3 >>expect &&
> + printf "\0" >>expect &&
> +
> + printf "1\0" >>expect &&
> + git merge-tree --write-tree -z --merge-base=c2 c1 c3 >>expect &&
> + printf "\0" >>expect &&
> + test_cmp expect actual
> +'
This last test seems odd. You are merely testing that the output of
"git merge-tree --stdin" matches the output of repeated calls to "git
merge-tree", not that the merges involved produce correct results?
Maybe that's fine since earlier tests verify that individual
merge-tree calls are doing the right thing, I was just a bit
surprised. Maybe a comment in the code that this was your intent
would be helpful?
