chiark / gitweb /
git-debrebase(5): wip, converting from README
[dgit.git] / README.git-debrebase
index fc96cd8269c80483cfcf806d201a8ac5d89cf72b..19ddbc05863d5fa3231b8494a6d3dbacce4a0dff 100644 (file)
@@ -1,93 +1,36 @@
 
 
-My preferred answer is that it is a constantly rebasing branch topped
-with a series of pseudomerges to make it fast-forwarding.
-
-           ------/--A!----/--B3!--%--/--> interchange view
-                /        /          /      with debian/ directory
-               %        %          %       all upstream changes applied
-              /        /          /        3.0 (quilt) has debian/patches
-             /        /          3*
-            /        /          /
-           2*       2*         2
-          /        /          /
-         1        1          1    `breakwater' branch, merging baseline
-        /        /          /     unmodified upstream code
-    ---p-----p--A----p--B--C-->   plus debian/ (but no debian/patches)
-      /     /       /
-   --#-----#-------#-----> upstream
-
-    Key:
-
-      1,2,3   commits touching upstream files only
-      A,B,C   commits touching debian/ only
-      B3      mixed commit (eg made by an NMUer)
-      #       upstream releases
-
-     -p-      special merge, takes contents of debian/ from the
-     /         previous `breakwater' commit and rest from upstream
-
-     -/-      pseudomerge; contents are identical to
-     /         parent lower on diagram.
-
-      %       dgit-generated commit of debian/patches.
-              `3.0 (quilt)' only; dropped by rebase tool.
-
-      *       Maintainer's HEAD was here while they were editing,
-              before they said they were done, at which point their
-              tools generated [% and] -/- commit[s] to convert to
-              the fast-forwarding interchange branch.  (Maybe the
-              tooling is simply `dgit push'.)
-
-      !       NMUer's HEAD was here when they said `dgit push'.
-              Rebase branch launderer turns each ! into an
-              equivalent *.
-
-
-Looking from the tip of the interchange view, it is I think always
-possible to classify these commits appropriately: pseudomerges are
-fairly obvious (if all three trees are identical, we descend to the
-parent with the most recent commit date), and the `p' special merge is
-the only non-pseudo merge and has a special form.
-
 So it would be possible to write a `git-debrebase' tool which would
 take (for example) B4, above, and be able to perform functions like:
 
  * Strip pseudomerges: Rewrite the current branch so it contains no
-   pseudomerges, turning ...B3 into ...p-A-1-2-B3.  (This should
-   make a note, in your .git/ somewhere, of the latest pseudomerge to
-   be deleted.)
+   pseudomerges, turning ...B3 into ...@-A-1-2-B3.  (This should
+   make a note, in your .git/ somewhere, of the original branch
+   tip so that it can be overwritten with a pseudomerge.)
 
  * Cleanup branch: Reorganise the current branch so that the debian/
-   changes come first, turning -p-A-1-2-B3 into ...p-A-B-1-2-3.
+   changes come first, turning -@-A-1-2-B3 into ...@-A-B-1-2-3.
 
  * New upstream rebase: Start rebasing onto a new upstream version,
-   turning ...#...p-A-B-1-2-3 into ...#'.A-B-p'-1-2.  This would be a
-   wrapper around git-rebase, which prepares p' and then tries to
-   rebase 1 2 onto p'.  So if you ask for an interactive rebase p'
-   doesn't appear in your commit list.
+   turning ...#..@-A-B-1-2-3 into (...#..@-A-B-|...#'-)@'-1-2.  This
+   would be a wrapper around git-rebase, which prepares @' and then
+   tries to rebase 1 2 onto @'.  So if you ask for an interactive
+   rebase @' doesn't appear in your commit list.
 
-   Note that the rebasing of p into p' cannot fail because p' simply
+   Note that the construction of @' cannot fail because @' simply
    copies debian/ from B and and everything else from #'.  (Rebasing A
    and B is undesirable.  We want the debian/ files to be non-rebasing
    so we can `git log' and get the packaging history.)
 
  * Record pseudomerge.  This is like "committing" your patch queue.
-   The LH parent is taken from the previous strip pseudomerge.  (We
-   should probably check that this is consistent with what we see in
-   debian/changelog, but that is not a sufficient check.)
+   The LH parent is taken from the previously recorded tip.  (We could
+   perhaps check that this is consistent with what we see in
+   debian/changelog, but that is not a sufficient check so the
+   recorded tip check is primary.)
 
 Maybe some of these operations should automatically edit
 debian/changelog.
 
-The only thing that this can't easily do is permit nonlinear (ie,
-merging) history on the `packaging-only' branch, because upstream
-might contain debian/ files too, so it is not possible to distinguish
-a merge of two `packaging-only' branches from the special merge `p'.
-(Indeed I since upstream might copy debian/ from us, I think it is not
-easy to reliably distinguish the two parents of a `p'.  In the most
-exciting edge case, upstream might `git merge' a previous instance of
-our interchange view, but I think even then everything still works.)
 
 Sean Whitton writes ("Re: Feedback on 3.0 source format problems"):
 >  Does the [breakwater] branch contain debian/ alone?
@@ -101,81 +44,77 @@ would get if you untarred the origs and the debian.tar.gz, and then
 deleted all the patches without applying them.
 
 
+dgit import handling
+--------------------
 
 Consider a non-dgit NMU followed by a dgit NMU:
-                                              
-                                 
-                                              
-            interchange --/--B3!--%--/----D*-->                    
-                         /          /                      
-                        %          4                       
-                       /          3                        
-                      /          2                         
-                     /          1                          
-                    2*         &_                          
-                   /          /| \                         
-                  1          0 00 =XBC% 
-                 /                                                 
-                /                                                  
-                 --p--A---> breakwater                             
-          /                                                
-       --#--------> upstream                               
-                                                           
-                                                           
- Key:                                                      
-                                                           
-    =XBC%     dgit tarball import of .debian.tar.gz containing   
-              Debian packaging including changes B C and patches 
-                                                                 
-    0         dgit tarball import of upstream tarball            
-                                                                 
+
+
+
+            interchange --/--B3!--%--/----D*-->
+                         /          /
+                        %          4
+                       /          3
+                      /          2
+                     /          1
+                    2*         &_
+                   /          /| \
+                  1          0 00 =XBC%
+                 /
+                /
+                 --@--A     breakwater
+          /
+       --#--------> upstream
+
+
+ Key:
+
+    =XBC%     dgit tarball import of .debian.tar.gz containing
+              Debian packaging including changes B C and patches
+
+    0         dgit tarball import of upstream tarball
     00        dgit tarball import of supplementary upstream tarball
-                                                                 
-    &_        dgit nearly-breakwater import                              
-                                                                 
-    &'        git-debrebase converted import                             
-                                                                 
-    D'        git-debrebase converted debian/ changes import     
-                                      
+    &_        dgit nearly-breakwater import
+    &'        git-debrebase converted import (upstream files only)
+    D'        git-debrebase converted debian/ changes import
+
     * **      before and after HEAD
-                                 
-Want to transform this into:                                     
-                                                                 
- I. No new upstream version (0 + 00 eq #)                               
-                                                                 
-                        --/--B3!--%--/------D*-------------/-->          
-                         /          /                    /       
-                        %          4                    4**      
-                       /          3                    3         
-                      /          2                    2          
-                     /          1                    1           
-                    2*         &_                   /            
-                   /          /| \                 /             
-                  1          0 00 =XBC%            /                    
-                 /                                       /                    
-                /                                       /             
-         --p--A-----B-----------------------C--D--->       
-          /                                                
-       --#----------------------------------------->       
-                                                           
-                                                           
- II. New upstream (0 + 00 neq #)                                   
-                                                                 
-                                 interchange                     
-                                                                 
-                        --/--B3!--%--/------E*-------------/-->          
-                         /          /                    /       
-                        %          4                    4**      
-                       /          3                    3         
-                      /          2                    2          
-                     /          1                    1           
-                    2*         &_                   /            
-                   /          /| \                 /             
-                  1          0 00 =XBC%            /           
-                 /                               /                    
-                /                               /             
-         --p--A-----B--------------------p--C--D--->     
-          /                             /           
+
+Want to transform this into:
+
+ I. No new upstream version (0 + 00 eq #)
+
+                        --/--B3!--%--/------D*-------------/-->
+                         /          /                    /
+                        %          4                    4**
+                       /          3                    3
+                      /          2                    2
+                     /          1                    1
+                    2*         &_                   /
+                   /          /| \                 /
+                  1          0 00 =XBC%            /
+                 /                                       /
+                /                                       /
+         --@--A-----B-----------------------C--D
+          /
+       --#----------------------------------------->
+
+
+ II. New upstream (0 + 00 neq #)
+
+                        --/--B3!--%--/------D*-------------/-->
+                         /          /                    /
+                        %          4                    4**
+                       /          3                    3
+                      /          2                    2
+                     /          1                    1
+                    2*         &_                   /
+                   /          /| \                 /
+                  1          0 00 =XBC%            /
+                 /                               /
+                /                               /
+         --@--A-----B--------------------@--C--D
+          /                             /
        --#----------------------- - -  /  - - ----->
                                       /
                                      &'