The git-history(1) command has the ability to perform a dry-run
that will not end up modifying any references. Instead, we'll only print
any ref updates that would happen as a consequence of performing the
operation.
This mode is somewhat hidden though behind the "--ref-action=print"
option. This command line option has its origin in git-replay(1), where
it's probably an okayish interface as this command is sitting more on
the plumbing side of tools. But git-history(1) is a user-facing tool,
and this way of achieving a dry-run is way too technical and thus not
very discoverable.
Besides usability issues, it also has another issue: the dry-run mode
will always operate as if the user wanted to rewrite all branches. But
in fact, the user also has the option to only update the HEAD reference,
and they might want to perform a dry-run of such an operation, too. We
could of course introduce "--ref-action=print-head", but that would
become even less ergonomic.
Replace "--ref-action=print" with a new "--dry-run" toggle. This new
toggle works with both "--ref-action={head,branches}" and is way more
discoverable.
Add a test to verify that both "--ref-action=" values behave as
expected.
This patch is best viewed with "--ignore-space-change".
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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