git-debrebase: Some notes on anchor parent ordering

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>