X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=blobdiff_plain;f=NOTES.git-debrebase;h=6a731f19cc1b0830783348c85c26e8dacb4ab4cb;hp=635f72bbbc5ddde5a431e0d8720f9496ac447f5c;hb=6f9e94728e55a5d52120760e6451e9ba48648051;hpb=1f4480c7fe42d8e997db608c35a3500de1052528

diff --git a/NOTES.git-debrebase b/NOTES.git-debrebase
index 635f72bb..6a731f19 100644
--- a/NOTES.git-debrebase
+++ b/NOTES.git-debrebase
@@ -47,6 +47,18 @@ overall format
 
 m{^\[git-debrebase (?:\w*-)?upstream combine \.((?: $extra_orig_namepart_re)+)\]}
 
+Every breakwater commit must be a merge.  In principle, this is not
+necessary.  After all, we are relying on the
+    [git-debrebase breakwater: ...]
+commit message annotation in "declare" breakwater merges (which
+do not have any upstream changes), to distinguish those breakwater
+merges from ordinary pseudomerges (which we might just try to strip).
+
+However, the user is going to be doing git-rebase a lot.  We really
+don't want them to rewrite a breakwater base commit.  git-rebase
+trips up on merges, so that is a useful safety catch.
+
+
 =========
 
 workflow
@@ -162,8 +174,50 @@ so that the overall result will be series of pseudomerges.
 
 ========================================
 
+So, pm handling specifics:
+
+strategy is to avoid making needless pseudomerges
+pseudomerges that exist will be preserved
+(by being included in will-overwrite)
+
+This is good because the presence of a pseudomerge means we know we
+want to keep it; and that allows explicit control over history detail
+level.
+
+It does mean we must avoid making the pseudomerges unnecessarily.
+They should be made just before (ideally, part of) dgit push.
+
+1. git-debrebase [-i etc.]
+
+     should:
+        check for will-overwrite
+        if is already a will-overwrite, fine, do no more
+        if not:
+
+        check our origin branch exists and we are ff from it
+        if not fail
+
+        check our other might-be-pushed to branches
+        check we are ff from them
+        if not fail
+
+        set will-overwrite to something which is ff from
+          all above branches
+
+        we use our tip, as discussed above
+        (optionally, can use some other commit which is ff
+         from all of the above, eg one of them)
+
+2. git-debrebase stitch
+
+    makes pseudomerge with will-overwrite
+    deletes will-overwrite
+
+========================================
+
 import from gbp
 
+[ all this is done now:
  inputs:
    current HEAD (patches-unapplied),
      this is going to be the base of the old breakwater
@@ -182,9 +236,13 @@ import from gbp
        commit to remove d/patches
        breakwater pseudomerge with upstream
        "rebase" of pq branch, each commit with d/patches stripped
+]
 
 what about dgit view branch ?
 ideally, would make pseudomerge over dgit view
 would need to check that dgit view is actually dgit view of
   ond of our ancestors
 failing that first push will need --overwrite
+
+should this be called import or gbp2debrebase as it is now ?
+gbp uses "import" oddly but I'm tempted to use it normally here.