X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=topbloke.git;a=blobdiff_plain;f=DESIGN;h=97f06810fe75996cfdfb35d656934e591a376465;hp=09cea32e66551b45d24848671b94e2251662db94;hb=098d1cf209a61beea78d08d84eb50509b132dd6d;hpb=7813c2240eeb9c10032dc14f91d362b84fa5f158

diff --git a/DESIGN b/DESIGN
index 09cea32..97f0681 100644
--- a/DESIGN
+++ b/DESIGN
@@ -22,7 +22,7 @@ Basic update algorithm:
 
        Find the (latest) common ancestor.
 
-       Check for unwanted dependency removals.  
+       Check for unwanted dependency removals.
        An unwanted dependency removal is
           A branch in the desired included deps
           Which exists in the common ancestor's actual included deps
@@ -112,7 +112,7 @@ Basic update algorithm:
 The "best order" for merges is in order of recency of common
 ancestor, most recent first, and if that does not distinguish,
 merging from local branches first.
-     
+
 "Recency" refers to the order from git-rev-list --date-order.
 
 Actual included deps:
@@ -225,7 +225,7 @@ OK so here is a plan:
   Check for merge success in the index and compare to exit status
   from git-merge (which is 1 if the merge failed).
   Adjust the metadata.
-  Print appropriate big fat warnings if we have merge conflicts in our 
+  Print appropriate big fat warnings if we have merge conflicts in our
   metadata.
   Commit, adjusting the parents of the new commit to the original
   parents if we made the merge with special massaged parents.
@@ -259,21 +259,85 @@ Unwanted removal search subgraphs:
 inc  inc..
 /  ???   \
 
-   rm		
+    rm
 inc..  rm..	merge of a removal, search down the rm path
 /  [inc]  \
 
   inc		??? call it an inclusion, terminate the search
   rm
 
-  inc		merge of an inclusion, terminates search
+   inc		merge of an inclusion, terminates search
 inc..  rm..
 /  [rm]  \
 
-  inc		??? call it an inclusion, terminate search
+   inc		??? call it an inclusion, terminate search
 rm..  rm..
 /  ???    \
-  
+
 
   rm	inc	  inc	       rm	irrelevant
   rm	inc	inc inc..    rm rm..
+
+
+
+          OUR BASE              SOURCE		       OUR IT TIP
+		| 	       	   |			   |
+		| 	           | 			   |
+   ADD DEP WH/ inc	       	   rm			   |
+    NEEDS IT   /|	       	   /\			   |
+	      /	| 	       	 rm  \			   |
+	     /	| ______________'/    \			   |
+	  inc	|'	       	/      \		   |   	 IT tip
+           /   inc     REMOVAL rm       \              	   |   	elsewhere
+          /     |             /          \             	   |   |   |
+	 /      |           inc           \                |   |   |
+     some IT    |           /              |           	   |   |   |
+                |         inc              |           	   |   |   |
+               /           |               |           	   |   |   |
+              /          inc               |           	   |   |   |
+             |           / |               |           	   |   |   |
+	    /           /  inc             |           	   |   |   |
+	   /           |   | `------------ | ----<-------- | -.|   |
+       	  /           inc  inc             |           	   |   *2  |
+	  |            |`- | ------------- | ----<--------.|   |   |
+	  |            `---inc             |           	  1*  /	   |
+ 	  |                |               |           	   | /	   |
+ 	  |     RE-INCLUDE inc             rm REMOVAL  	   |'	   |
+        inc     \          |               |           	   |	   |
+    	  |      * REMOVAL rm              |           	   |	   |
+       	  |                |              /            	   |	   |
+       	  |`-------------- | ----------. /             	   |	   |
+       	  |                |           inc ANC2        	   |	   |
+ 	 inc               inc         /               	   |	   |
+ 	  |`.____________  |          /                	   |	   |
+ 	  |              `inc ANC1   /                 	   |	   |
+ 	  |                |        /`--------<----------- | ---.  |
+ 	without            inc     /                   	   |	 \/
+ 	  |                |      /                    	   |	 /
+ 	   \    RE-INCLUDE inc   /                     	   |   	/
+       	    \   \          |    /                      	   |   /
+ 	     \   * REMOVAL rm  /                       	   |  /
+              \            |  /                        	   | /
+               \           inc FIRST ADD DEP   	       	   |/
+		\	   |  \	       	       	       	   *3
+		 \	   |   `------------<-------------.|
+       	       	  \    	   | 	      		       	   |
+ 		   \	   without    		       	   |
+		    \_____ |   	      		       	   |
+		 	  `without    		       	   |
+		 	   |   	      		    	   |
+		 		      		       	  IT
+
+
+  Merge 1* and 2*, diff against some relevant base branch commit
+  or something, and apply to proposed. ???
+
+
+After we are done:
+  source tip is included in our base
+
+Each time:
+  * pick common ancestor
+  * compute whether merge from common anc would unwantedly remove
+  * if so we arrange that the common anc is a "rm" but our branch
+    actually contains IT