git-debrebase: Use git-deborig style upstream commitish finding

As discussed in email with Sean.

We could use git-deborig --just-print --version= but its error
handling is rather troublesome.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Add some plans for future, in a comment

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

test suite: gdr-edits: Rely on dgit interop, and test that it DTRT

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: t-gdr-good: Introduce etypes, a sequence

Rather than having the next type recorded in netype, record it in
etypes.  This is more orthogonal, and will allow more subtle
specifications of what is expected.

No functional change for now.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

dgit: Interoperate with git-debrebase, automatically

* Recognise gdr branches, by the presence of corresponding
  ffq-prev or debrebase-last refs.

* Before trying to do our own multi-patch linear quilt fixup, on a gdr
  branch, see if gdr can do it.  If so that is faster and better.

* If our branch is an unstitched gdr branch, which would be ff from
  the archive if we were to stitch it, then do so.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

dgit: Prepare for calling git-debrebase

Provide the --git-debrebase= option, and pass it in the test suite.
Nothing uses this yet.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

Dgit.pm: gdr_ffq_prev_branchinfo: move from git-debrebase

dgit is going to want this too, for interoperability.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: make-patched: Provide --quiet-would-amend

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: provide X checkletter

No user yet.  I wanted this for a test which actually isn't going to
work like that, but I thought I would commit it anyway.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: use xopts for N*

This stylistic change improves the orthogonality.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: split off XX

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: honour new $xopts

This allows the introduction of chaining checkletters which modify
subsequent attempts.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: document XX

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Change exit status for patch amendments, to 7

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: make_patches; Move get_differs into cmd_...

We want to make the error handling dependent on options, etc.  Moving
the differs analysis into cmd_make_patches avoids having a complex
calling convention for make_patches.

No functional change.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

Dgit.pm: Provide failmsg, previously buried in fail

Most of `fail' is error message construction.  This change allows
callers to do something other with the message, than pass it to die.

No functional change.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: run gdr status

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Provide status subcommand

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: keycommits: Now $fatal hook

This allows a caller to avoid having keycommits crash on
unrecognisable stuff.  This will be used in a moment.

No functional change, because the default implementation calls fail
the same way it did before.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: keycommits abolish use of last etc.

Previously, presumably, this little fragment was within an anonymous
sub.  Now it isn't any more, and we can simply return.

No functional change.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: keycommits: Pass $cl to callbacks

No overall functional change.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: keycommits: Move up $cl (nfc)

We are going to want this within the scope of the anon sub $x.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Fix multi-orig handling

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Fix snagging

* Rename $snags_checked to $snags_summarised and make it a counter
  of the snags we have summarised in snags_maybe_bail.
* Introduce all_snags_summarised, which uses arithmetic to see if
  we have had new snags since the most recent snags_maybe_bail,
* Use this in run_deferred_updates rather than the existing
  approach; this means we can crash if there were new snags for
  which we should have bailed.
* Make snags_maybe_bail not produce a redundant identical summary.
* Initialise counters to 0 so arithmetic does not give undef warnings.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Some notes on anchor parent ordering

This is the result of some playing around with gitk.  Notably,
for example,
  git-branch -f t dgit/stretch-security && ~/things/Dgit/play/swap-pseudomerges -f RELEASE-4.8.0..t
where dgit/stretch-security is c9517ee45383271e90f40b7a9773d1e6fefaeca7
and swap-pseudomerges is something like this

  #!/bin/sh
  #
  # runs
  #   git-filter-branch --some-filters "$@"

  set -e

  git-filter-branch --parent-filter '
  case "$(git cat-file commit $GIT_COMMIT)" in
  *"git-debrebase new-upstream breakwater"*|*"git-debrebase anchor"*)
  perl -ne '\''
  chomp;
  print join " ", reverse split / +(?=-p )/;
  print "\n";
  '\''
  ;;
  *)
  cat
  esac
  ' "$@"

or
  ....
*"git-debrebase new-upstream breakwater"*|*"git-debrebase anchor"*)
  ....

and then runes like

  gitk --first-parent dgit/stretch-security &
  gitk dgit/stretch-security -- ':/' ':!/debian' &

etc.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

Commentary: explain why pseudomerges are the way round they are

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

dgit: Bail if single-debian-patch needs committing with --quilt=nofix

Also, if the user invokes dgit push with uncommitted debian/patches/.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

dgit: Break out quiltify_nofix_bail (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Change badusage exit status to 8

This matches dgit.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

exit status: Document in changelog.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

exit status: Fix dgit-badcommit-fixup to use Debian::Dgit::ExitStatus

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

exit status: Fix git-debrebase to use Debian::Dgit::ExitStatus

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

exit status: Fix dgit to use Debian::Dgit::ExitStatus

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

exit status: Introdude Debian::Dgit::ExitStatus

No callers yet.

Also, no version for dgit-infrastructure.  The one perl script in
dgit-infrastructure that cares a lot about its exit status
(dgit-repos-policy-debian) already has an END { } and uses _exit,
which is a bit like our approach here, but simpler.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Implement make-patches

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: Add some t-git-next-date

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Run gbp pq export only from (perhaps private) laundered branch

When the branch is stitched, gbp pq will descend into both sides of
the pseudomerge.  This will duplicate patches and be generally bad.

So instead, use walk to generate, privately, a laundered version of
HEAD, to use to generate the patches.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Break out make_patches_staged (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: conclude, quick: uncleanness after laundry is fatal

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Defend against missing snags_maybe_bail calls

Almost the only thing gdr does as an output is to update HEAD and
other refs.  That's done with run_deferred_updates.  So, there,
check that (i) we have called snags_maybe_bail at least once;
(ii) we have not had any snags since.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Add a several missing snags_maybe_bail calls

That these were missing is a bit alarming.  I am about to add some
more defences against missing this check.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Fix a message to use "" properly

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: gdr-subcommands: Better error handling/debugging

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Do not mind stitching an unlaundered branch

 <Diziet> I discover that stitch treats non-launderedness as a snag.
 <Diziet> This is not quite compatible with these newfangled
          push-your-unlaundered-stuff workflows.
 <Diziet> It would be possible to make one of prepush or stitch
          (currently synonyms) behave differently in this respect.

 <spwhitton> do you know why stitch treats non-launderedness as a snag?
 <spwhitton> given that we expect [most people] to use `git debrebase
          conclude`, which launders, and never invoke `git debrebase
          stitch` explicitly, it would be okay to change that such
          that `git debrebase stitch` does not consider
          non-launderedness to be a snag.

 <Diziet> I think it does that just because I am the kind of person
          who thinks, when writing some routine, "what could I check
          here?" :-)
 <Diziet> I think you are perhaps right that it ought not to.
 <Diziet> "conclude" didn't exist then of course.

 <spwhitton> okay.  git-debrebase(1) could note "you probably want
          conclude because you probably want to launder"

 <Diziet> Mmmm.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: do_stitch: Introduce $unclean argument

Update all call sites.  No functional change just yet.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Provide "prepush"

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Provide and test "conclude"

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): Fix to say that noop is always ok for "quick"

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): Very minor clarification to "quick"

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: test suite: New test for subcommands

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Rename `conclude' to `quick'

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: comment: explain why tagged linear anchors are evil

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Only make finalised changelog entries

Unfortunately, finalised UNRELEASED has become the dominant convention
in Debian.  So conform to that.

Also this breaks a test, which assumed that the operation date did not
leak into the output tree.  But, sadly, now it does.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Do not run a no-op rebase in default mode

No functional change: this is always a no-op, since $breakwater is one
of HEAD's ancestors.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Handle -i option as a git-rebase option

Ie, as a request to do a rebase.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Provide conclude subcommand

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: break out do_stitch (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: avoid stack trace from badusage()

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Improve/fix handling of $prose

Allow specification of the whole prose.  Set the default in
cmd_stitch.  Always include the word `stitch' in the reflog.

Also fix a comment typo.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Rename `problem'/`fproblem' to `snag'

And add a cross-reference the first time it's mentioned in the
manpage.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: introduce ffq_prev_info (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Break out do_launder_head (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: break out stitch() (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: rename $drlast to $gdrlast (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): Further manpage improvement

Prompted by email from Sean.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): We are going to generate patches ourselves

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Corrections and clarifications to dgit import

Also untabify those diagrams.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Untabify the diagram a bit

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Some minor cross-reference additions to TERMINOLOGY

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1),(5): More changes from conversation with Sean

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Move TERMINOLOGY earlier

As suggested by Sean.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Improvements from Sean

Suggested in or prompted by Sean's mail of 28th March.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Rework the description a bit

Mention whether branches and branch states are ff.  And describe the
breakwater.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): Improvements from Sean

Suggested in or prompted by Sean's mail of 28th March.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Provide anchor subcommand

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: Rework keycommits out of breakwater_of

* Return the anchor too
* More flexible special case handling
* Call sites adjusted, resulting in fixes to special case handling

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: stitch: make noop actually be a no-op

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: stitch: check the branch is laundered

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: breakwater_of: permit unclean to be an fproblem

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: maintain debrebase-last

This is mostly for the benefit of dgit(1), which wants to know whether
to run gdr to do quilt fixup.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: ffq_prev_branchinfo: return $drlast

No functional change yet as no-one uses this information.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

Dgit.pm: provide $gdrlast_refprefix

No users yet so no functional change.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): minor improvements

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: NOTES updates

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase: move some todo/notes to NOTES

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): document options

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): ship

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): document record-ffq-prev

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): document some more

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): document convert-to-gbp

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): document convert-from-gbp

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(1): wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): finished now I think

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Document commit message annotations

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): Terminology fixes, cleanups

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): All of README now in (5)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): more from README

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): tidying up

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

git-debrebase(5): copy more stuff from README

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>