strategy: wip ends reachability

[topbloke-formulae.git] / strategy.tex

diff --git a/strategy.tex b/strategy.tex
index bfd392224d6e5c854573b4988f4314fd66d40530..97c41b9a9b0a1e55ea45e085746a3909f08b317b 100644 (file)
--- a/strategy.tex
+++ b/strategy.tex
@@ -109,3 +109,29 @@ as generated by the Traversal phase of the update algorithm.
 
 \end{basedescript}
 
+\stdsection{ WIP tip satisfaction, reachable commits }
+
+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), 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.
+
+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_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 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
+
+