reflog: improve and update documentation

Revamp the "git reflog" usage documentation in the manpage and the
command help to match the current reality and improve its clarity:

* Add documentation for some options that had been left out.

* Group the subcommands and options more logically and move more
  common subcommands/options higher.

* Improve some explanations.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Michael Haggerty 2015-03-03 12:43:15 +01:00 committed by Junio C Hamano
parent 5a6f47077b
commit fe2a18165c
2 changed files with 86 additions and 62 deletions

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@ -17,85 +17,112 @@ The command takes various subcommands, and different options
depending on the subcommand:
[verse]
'git reflog expire' [--dry-run] [--stale-fix] [--verbose]
[--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...
'git reflog delete' ref@\{specifier\}...
'git reflog' ['show'] [log-options] [<ref>]
'git reflog expire' [--expire=<time>] [--expire-unreachable=<time>]
[--rewrite] [--updateref] [--stale-fix]
[--dry-run] [--verbose] [--all | <refs>...]
'git reflog delete' [--rewrite] [--updateref]
[--dry-run] [--verbose] ref@\{specifier\}...
Reflog is a mechanism to record when the tip of branches are
updated. This command is to manage the information recorded in it.
Reference logs, or "reflogs", record when the tips of branches and
other references were updated in the local repository. Reflogs are
useful in various Git commands, to specify the old value of a
reference. For example, `HEAD@{2}` means "where HEAD used to be two
moves ago", `master@{one.week.ago}` means "where master used to point
to one week ago in this local repository", and so on. See
linkgit:gitrevisions[7] for more details.
The subcommand "expire" is used to prune older reflog entries.
Entries older than `expire` time, or entries older than
`expire-unreachable` time and not reachable from the current
tip, are removed from the reflog. This is typically not used
directly by the end users -- instead, see linkgit:git-gc[1].
This command manages the information recorded in the reflogs.
The subcommand "show" (which is also the default, in the absence of any
subcommands) will take all the normal log options, and show the log of
the reference provided in the command-line (or `HEAD`, by default).
The reflog will cover all recent actions (HEAD reflog records branch switching
as well). It is an alias for `git log -g --abbrev-commit --pretty=oneline`;
see linkgit:git-log[1].
The "show" subcommand (which is also the default, in the absence of
any subcommands) shows the log of the reference provided in the
command-line (or `HEAD`, by default). The reflog covers all recent
actions, and in addition the `HEAD` reflog records branch switching.
`git reflog show` is an alias for `git log -g --abbrev-commit
--pretty=oneline`; see linkgit:git-log[1] for more information.
The reflog is useful in various Git commands, to specify the old value
of a reference. For example, `HEAD@{2}` means "where HEAD used to be
two moves ago", `master@{one.week.ago}` means "where master used to
point to one week ago", and so on. See linkgit:gitrevisions[7] for
more details.
The "expire" subcommand prunes older reflog entries. Entries older
than `expire` time, or entries older than `expire-unreachable` time
and not reachable from the current tip, are removed from the reflog.
This is typically not used directly by end users -- instead, see
linkgit:git-gc[1].
To delete single entries from the reflog, use the subcommand "delete"
and specify the _exact_ entry (e.g. "`git reflog delete master@{2}`").
The "delete" subcommand deletes single entries from the reflog. Its
argument must be an _exact_ entry (e.g. "`git reflog delete
master@{2}`"). This subcommand is also typically not used directly by
end users.
OPTIONS
-------
--stale-fix::
This revamps the logic -- the definition of "broken commit"
becomes: a commit that is not reachable from any of the refs and
there is a missing object among the commit, tree, or blob
objects reachable from it that is not reachable from any of the
refs.
+
This computation involves traversing all the reachable objects, i.e. it
has the same cost as 'git prune'. Fortunately, once this is run, we
should not have to ever worry about missing objects, because the current
prune and pack-objects know about reflogs and protect objects referred by
them.
Options for `show`
~~~~~~~~~~~~~~~~~~
--expire=<time>::
Entries older than this time are pruned. Without the
option it is taken from configuration `gc.reflogExpire`,
which in turn defaults to 90 days. --expire=all prunes
entries regardless of their age; --expire=never turns off
pruning of reachable entries (but see --expire-unreachable).
`git reflog show` accepts any of the options accepted by `git log`.
--expire-unreachable=<time>::
Entries older than this time and not reachable from
the current tip of the branch are pruned. Without the
option it is taken from configuration
`gc.reflogExpireUnreachable`, which in turn defaults to
30 days. --expire-unreachable=all prunes unreachable
entries regardless of their age; --expire-unreachable=never
turns off early pruning of unreachable entries (but see
--expire).
Options for `expire`
~~~~~~~~~~~~~~~~~~~~
--all::
Instead of listing <refs> explicitly, prune all refs.
Process the reflogs of all references.
--expire=<time>::
Prune entries older than the specified time. If this option is
not specified, the expiration time is taken from the
configuration setting `gc.reflogExpire`, which in turn
defaults to 90 days. `--expire=all` prunes entries regardless
of their age; `--expire=never` turns off pruning of reachable
entries (but see `--expire-unreachable`).
--expire-unreachable=<time>::
Prune entries older than `<time>` that are not reachable from
the current tip of the branch. If this option is not
specified, the expiration time is taken from the configuration
setting `gc.reflogExpireUnreachable`, which in turn defaults
to 30 days. `--expire-unreachable=all` prunes unreachable
entries regardless of their age; `--expire-unreachable=never`
turns off early pruning of unreachable entries (but see
`--expire`).
--updateref::
Update the ref with the sha1 of the top reflog entry (i.e.
<ref>@\{0\}) after expiring or deleting.
Update the reference to the value of the top reflog entry (i.e.
<ref>@\{0\}) if the previous top entry was pruned.
--rewrite::
While expiring or deleting, adjust each reflog entry to ensure
that the `old` sha1 field points to the `new` sha1 field of the
previous entry.
If a reflog entry's predecessor is pruned, adjust its "old"
SHA-1 to be equal to the "new" SHA-1 field of the entry that
now precedes it.
--stale-fix::
Prune any reflog entries that point to "broken commits". A
broken commit is a commit that is not reachable from any of
the reference tips and that refers, directly or indirectly, to
a missing commit, tree, or blob object.
+
This computation involves traversing all the reachable objects, i.e. it
has the same cost as 'git prune'. It is primarily intended to fix
corruption caused by garbage collecting using older versions of Git,
which didn't protect objects referred to by reflogs.
-n::
--dry-run::
Do not actually prune any entries; just show what would have
been pruned.
--verbose::
Print extra information on screen.
Options for `delete`
~~~~~~~~~~~~~~~~~~~~
`git reflog delete` accepts options `--updateref`, `--rewrite`, `-n`,
`--dry-run`, and `--verbose`, with the same meanings as when they are
used with `expire`.
GIT
---
Part of the linkgit:git[1] suite

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@ -8,14 +8,11 @@
#include "revision.h"
#include "reachable.h"
/*
* reflog expire
*/
/* NEEDSWORK: switch to using parse_options */
static const char reflog_expire_usage[] =
"git reflog expire [--verbose] [--dry-run] [--stale-fix] [--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...";
"git reflog expire [--expire=<time>] [--expire-unreachable=<time>] [--rewrite] [--updateref] [--stale-fix] [--dry-run | -n] [--verbose] [--all] <refs>...";
static const char reflog_delete_usage[] =
"git reflog delete [--verbose] [--dry-run] [--rewrite] [--updateref] <refs>...";
"git reflog delete [--rewrite] [--updateref] [--dry-run | -n] [--verbose] <refs>...";
static unsigned long default_reflog_expire;
static unsigned long default_reflog_expire_unreachable;