-relations
- ancestry: of commits, a partial order
- C > D C is a descendant of D
- inclusion: commit includes change made in another
- a partial order, consistent with ancestry but more partial
- C has D <=> D isin C
- C has D => C > D
-
-define convenience function
- cont(C) := { Cx | Cx isin C }
-
-patches
- patch P is two sets Px of commits, Ptip and Pbase
- each subset has a single ur-ancestor C0_Ptip resp C0_Pbase
- all these subsets Ptip,Qbase,Rtip,Sbase mutually exclusive
- P(C) is either Ptip, Pbase, or nil (recorded in commit)
-
-commits fall into three categories wrt P
- inpatch(P,C) = included
- P included in C
- \forall D \elem Ptip, C has D <=> C > D
- inpatch(P,C) = absent
- P absent from C
- \forall D \elem Ptip, !(C has D)
- inpatch(P,C) = removed
- P removed from C
- cont(C) \intersection Ptip = { }
- but maybe \exists Cx \elem Ptip s.t. Cx < C
-
-the ends E(C,Px) of Px = Pbase or Ptip are
- every maximal Ce < C in Px
- ie every Ce for which
- C > Ce and !\exists C s.t. C > Ce
-
-existence of corresponding base B for every tip commit C
- \forall C s.t. P(C) = Ptip
- \exists B s.t. E(C,Pbase) = { B }
- resulting function B(C)
-
-contents of tip commits
- \forall C s.t. P(c) = Ptip
- cont(C) = cont(B(C)) \union { Cp s.t. P(Cp) = Ptip and Cp < C }
-
-non-circularity
- \forall B s.t. P(c) = Pbase
- cont(B) \notintersect Ptip
-
-normal commits
- make C from D
- result
- C < { D }
- P(C) = P(D)
- Cx isin C <=> Cx = D v Cx isin D
- inpatch(P,C) = inpatch(P,D)
-
-anticommit for removing a patch P from D to make C
- make C from D, A-
+GENERAL
+
+ C >= D C is descendant of D, partial order
+ C \haspatch D C contains changes from D, partial order
+ Patch P has two sets P+, P-
+ Ancestors A(C,P) = { Ca \elem C | Ca \elem P }
+ Ends E(C,P) = maximal elements of A(C,P)
+ Patch inclusion
+ C \haspatch P <=> [ \forall D \elem P+: D \isin C <=> D <= C ]
+ C \nothaspatch P <=> [ \forall D \elem P+: D \notisin C ]
+
+COMMIT ANNOTATIONS
+
+ Commit C is annotated with:
+
+ P(C)
+ Either P s.t. C \elem P
+ or _|_ meaning \notexists_{P} C \elem P.
+
+ { Pi | C \haspatch Pi }
+ ie the set of included patches
+
+ For every Px, E(C,Px+)
+ Implicitly for C \elem Pc+, E(C,Pc+) = { C }
+ and this is not annotated explicitly.
+ Also implicitly for P(C) = _|_, \forall_{Px} E(C,Px+) = { }
+ and this is also not annotated explicitly.
+
+ B(C)
+ For C \elem P+: B s.t. E(C,P-) = { B }
+ P(C) = P- or _|_: _|_
+
+ Of these in principle all except P(C) can be recalculated from the
+ commit history, but that would involve a complete history scan and in
+ the case of \haspatch is clearly impractical. At some point we may
+ provide a checker/sanitiser that recalculates E(C,Px+) and B(C) from
+ the commit history.
+
+SIMPLE COMMIT
+
+ make C >1 { A }
+ from A
+
+ with contents
+ D \isin C <=> D \isin A v D = C
+
+ results
+ P(C) = P(A)
+ A \haspatch P <=> C \haspatch P
+ For A \notelem Px+: E(C,Px+) = E(A,Px+)
+ A \elem Px+: E(C,Px+) = { C } -- not annotated
+
+ANTICOMMIT
+
+ make C >1 { L }
+ from L, R+, R-
+
+ with contents
+ D \isin C <=> D \notelement Pr+ ^ D \isin L
+
where
- P(C) = Qbase
- P(A-) = Ptip
- inpatch(P,C) = included
- E(D,Ptip) = { A- }
- then let
- A+ = B(A-)
- hence
- A+ < A- < D
- E(D,Pbase) = { A+ }
- result
- C >1 { D }
- P(C) = P(D)
- inpatch(P,C) = removed
-
-single patch dependency application
- make C from D, A+
+ P(R+) = Pr+, P(R-) = Pr-
+ E(L,Pr+) = { R+ } -- nontrivial, may need R+' = merge of E(L,Pr+)
+ B(R+) = R-
+ L \haspatch Pr
+
+ results
+ P(C) = P(L) = Pl-
+ If C \elem P+, B(C) = B(L); otherwise B(C) n/a
+ For P = Pr: C \nothaspatch Pr
+ E(C,Pr+) = E(L,Pr+) = { R+ }
+ P != Pr: C \haspatch P <=> L \haspatch P
+ E(C,P+) = E(L,P+)
+
+MERGE
+
+ make C >1 { L, R }
+ from L, R, M
+
+ with contents
+ D \isin C <=> [ (D \isin L ^ D \isin R) v D = C : T ]
+ [ D \notisin L ^ D \notisin R ^ D != C : F ]
+ [ otherwise : D \notisin M ]
+
+ where
+ M < L, M < R
+ If L \elem P+:
+ R \elem P+ ^ B(R) = B(L) -- only merge tips with same base
+ v R \elem P- ^ R >= B(L) ^ M = B(L) -- base when merging into tip
+ If L \elem P-:
+ R \nothaspatch P
+ If L \haspatch P <=/=> R \haspatch P:
+ \forall Ce \elem E(R,P+): Ce <= L -- may need to merge E(R,P+) into L
+
+ results
+ P(C) = P(L)
+ B(C) =
+ For C \notelem P+: n/a
+ C \elem P+, R \elem P+: B(L) = B(R)
+ C \elem P+, R \notelem P+: R >= B(L)
+
+ C \haspatch P =
+ For L \nothaspatch P, R \nothaspatch P: F
+ L \haspatch P, R \haspatch P: T
+ otherwise: M \nothaspatch P
+ E(C,P+) = maximal elements of E(L,P+) \union E(R,P+)
+ = { Cl | \notexist Cr \elem E(R,P+): Cr >= Cl } \union
+ { Cr | \notexist Cl \elem E(L,P+): Cl >= Cr }
+
+ -- to reintroduce a dep, set P(C)=P(L)=Pl-, P(R)=Pr+, M=B(R)
+ where L \notelem Pr obv.
+
+
+CREATE BASE
+
+ make B >1 { L }
+ from L, P
+
where
- P(C) = Qbase
- P(A+) = Ptip
- inpatch(P,C) != included
- then let
- A- = B(A+)
- hence
- A- < A+
- result
- C >1 { D, A+ } => C > D, C > A+ > A-
- P(C) = P(D)
- inpatch(P,C) = included
-
-simple merge
- make C from L, R, M
+ P(L) = Pl+ v P(L) = _|_
+ P(L) != P(B)
+ E(B,P+) = { }
+
+ with contents
+ D \isin B <=> D \isin L v D = B
+
+ results
+ P(B) = Pb-
+ B(C) n/a
+ E(B,Px+) = E(L,Px+)
+ B \haspatch P <=> L \haspatch P
+
+
+CREATE TIP
+
+ make C >1 { B}
+ from B
+
where
- M < L < C
- M < R < C
- result
- C >1 { L, R }
- P(C) = P(L)
- if Cx isin L = Cx isin R,
- Cx isin C = Cx isin L
- otherwise
- Cx isin C = ! Cx isin M
-
- cases of inpatch(P,L) and ,R
-
- or Cx isin
+ B \elem Pb-
+ E(B,P+) = { }
+
+ with contents
+ D \isin C <=> D \isin B v D = C
+
+ results
+ P(C) = Pb+
+ B(C) = B
+ C \haspatch P =
+ For P != Pb: B \haspatch P
+ P = Pb: T
~ian / topbloke.git / blobdiff