Re: [PATCH v3 8/8] fetch: introduce machine-parseable "porcelain" output format
- From
Glen Choo <chooglen@google.com>
- Date
- May 8, 2023, 23:42 UTC
- Message-ID
- <kl6lild21jbd.fsf@chooglen-macbookpro.roam.corp.google.com>
- In-Reply-To
- <e132d9494ee7d8c4eb3a7a82b6420743c8c7a9b0.1683113177.git.ps@pks.im>
This version looks great! I only have minor comments.
Patrick Steinhardt <ps@pks.im> writes:
Show 17 quoted lines
> A notable ommission here is that the output format does not include the > remote from which a reference was fetched, which might be important > information especially in the context of multi-remote fetches. But as > such a format would require us to print the remote for every single > reference update due to parallelizable fetches it feels wasteful for the > most likely usecase, which is when fetching from a single remote. > > In a similar spirit, a second restriction is that this cannot be used > with `--recurse-submodules`. This is because any reference updates would > be ambiguous without also printing the repository in which the update > happens. > > Considering that both multi-remote and submodule fetches are rather > niche and likely not going to be useful for the majority of usecases > these omissions feel acceptable. If usecases for either of these come up > in the future though it is easy enough to add a new "porcelain-v2" > format that adds this information.
As a point of clarification, I think these options aren't niche in themselves, but they are more user-facing, so using them _in conjunction with_ --porcelain is probably pretty niche, so I think this is okay for now.
Show 34 quoted lines
> --- a/Documentation/fetch-options.txt > +++ b/Documentation/fetch-options.txt > @@ -78,6 +78,12 @@ linkgit:git-config[1]. > --dry-run:: > Show what would be done, without making any changes. > > +--porcelain:: > + Print the output to standard output in an easy-to-parse format for > + scripts. See section OUTPUT in linkgit:git-fetch[1] for details. > ++ > +This is incompatible with `--recurse-submodules=[yes|on-demand]`. > + > ifndef::git-pull[] > --[no-]write-fetch-head:: > Write the list of remote refs fetched in the `FETCH_HEAD` > diff --git a/Documentation/git-fetch.txt b/Documentation/git-fetch.txt > index fba66f1460..f123139c58 100644 > --- a/Documentation/git-fetch.txt > +++ b/Documentation/git-fetch.txt > @@ -204,6 +204,15 @@ representing the status of a single ref. Each line is of the form: > <flag> <summary> <from> -> <to> [<reason>] > ------------------------------- > > +When using `--porcelain`, the output format is intended to be > +machine-parseable. In contrast to the human-readable output formats it > +thus prints to standard output instead of standard error. Each line is > +of the form: > + > +------------------------------- > +<flag> <old-object-id> <new-object-id> <local-reference> > +------------------------------- > + > The status of up-to-date refs is shown only if the --verbose option is > used.
I hadn't commented on the docs before, but they are very clear. Thanks!
Show 17 quoted lines
> @@ -1830,6 +1857,7 @@ struct parallel_fetch_state {
> const char **argv;
> struct string_list *remotes;
> int next, result;
> + enum display_format format;
> };
>
> static int fetch_next_remote(struct child_process *cp,
> @@ -1849,7 +1877,7 @@ static int fetch_next_remote(struct child_process *cp,
> strvec_push(&cp->args, remote);
> cp->git_cmd = 1;
>
> - if (verbosity >= 0)
> + if (verbosity >= 0 && state->format != DISPLAY_FORMAT_PORCELAIN)
> printf(_("Fetching %s\n"), remote);
>
> return 1;Here and elsewhere, I wonder if it's clearer to name the variable "porcelain" and separate it from "enum display_format". Then we can check "porcelain" directly instead of using "format == DISPLAY_FORMAT_PORCELAIN" as a proxy...
Show 19 quoted lines
> +static int opt_parse_porcelain(const struct option *opt, const char *arg, int unset)
> +{
> + enum display_format *format = opt->value;
> + *format = DISPLAY_FORMAT_PORCELAIN;
> + return 0;
> +}
> +
> int cmd_fetch(int argc, const char **argv, const char *prefix)
> {
> const char *bundle_uri;
> @@ -2104,6 +2140,8 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
> PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
> OPT_BOOL(0, "dry-run", &dry_run,
> N_("dry run")),
> + OPT_CALLBACK_F(0, "porcelain", &display_format, NULL, N_("machine-readable output"),
> + PARSE_OPT_NOARG|PARSE_OPT_NONEG, opt_parse_porcelain),
> OPT_BOOL(0, "write-fetch-head", &write_fetch_head,
> N_("write fetched references to the FETCH_HEAD file")),
> OPT_BOOL('k', "keep", &keep, N_("keep downloaded pack")),e.g. since we are reusing the "display_format" variable, we need to make sure we parse "--porcelain" after we read "fetch.output". I double-checked to make sure we were doing the right thing, though it would be nice to not have to worry about those sorts of things. This shouldn't hold up the series though.
Show 15 quoted lines
> +test_expect_success 'fetch porcelain with multiple remotes' ' > + test_when_finished "rm -rf porcelain" && > + > + git clone . porcelain && > + git -C porcelain remote add second-remote "$PWD" && > + git -C porcelain fetch second-remote && > + > + test_commit --no-tag multi-commit && > + old_commit=$(git rev-parse HEAD~) && > + new_commit=$(git rev-parse HEAD) && > + > + cat >expect <<-EOF && > + $old_commit $new_commit refs/remotes/origin/force-updated > + $old_commit $new_commit refs/remotes/second-remote/force-updated > + EOF
The only thing in this test that relies on the previous test is that HEAD is pointing to "force-updated", and it's hard to tell where HEAD is since the previous test is so long. Could we create a new branch instead?