From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 14 Jul 2012 00:57:44 +0000 (+0100)
Subject: strategy: wip ends reachability
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=topbloke-formulae.git;a=commitdiff_plain;h=13a217e73c1ab13c7899dd2c1be7cbc909fed331;ds=sidebyside

strategy: wip ends reachability
---

diff --git a/strategy.tex b/strategy.tex
index 833f5bd..97c41b9 100644
--- a/strategy.tex
+++ b/strategy.tex
@@ -115,45 +115,23 @@ Set of all reachable commits, O.
 
 A reachable commit is one we might refer to explicitly in any of these
 algorithms, and any ancestor of such a commit.  We explicitly
-enumerate all of the input commits (U).  And each commit we generate
-will be descended from zero or more of these.
+enumerate all of the input commits (U), so the reachable commits are
+originally the input commits and their ancestors.  Each commit we
+generate will have reachable commits as ancestors so when we generate
+a new commit we only add that new commit to O.
 
-Naturally this set varies over time as we generate more commits.  We
-write O_pyn for the set of reachable commits at the point where we
-have just generated T_pyn.
+So O varies over time as we generate more commits.  We write O_py for
+the set of reachable commits at the point where we have just generated
+T_py, ie jusjt after Merge-Tip(P).
 
 We preserve/ensure
-  Tip_Pyn >= pendsof( O_pyn, Pyn )
-(Tip_pyn is computed during traversal for the patch p)
+  Tip_Py >= pendsof( O_py, Py )
+(Tip_py is computed during traversal for the patch P)
 
 We ensure this property by:
-  - we do not generate any commits for pyn other than
-    during traversal for pyn
-  - so at the start of traversal pendsof ( O, pyn) = pendsof (U, pyn)
-  - the traversal steps will takes those pends
-
-  - during traversal for the patch set pyn
-    pendsof 
-
-  - arranging that during traversal for the patch set pyn
-     
-, we firstly
-    compute a tip_pyn which is >= pendsof(O) as follows:
-      there is a set of relevant ends
-              pendsof(U, 
-
-      we initially set T
-
-    by virtue of it being  >= pendsof(U) \cup
-    all lower tip_qyn
- - 
-
-We do this by:
- - firstly, Tip_pyn is only valid af
-  
-
-Set of all reachable commits in a particular patch set.
- This consists of
-  - input commits
-  - 
+  - we do not generate any commits for py other than
+    during Merge-Tip
+  - so at the start of Merge-Tip pendsof (O, py) = pendsof (U, py)
+  - Merge-Tip itself wip wip wip
+