X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=topbloke-formulae.git;a=blobdiff_plain;f=old-strategy.tex;fp=old-strategy.tex;h=da8ff9ce77d9e253a5c93028631ef921fa1ec4db;hp=0000000000000000000000000000000000000000;hb=fdd5c703b15790389545f3b12264dbe24db5033e;hpb=63cc1534200cc7fcafa007f8c6704fc8ac9c9fec diff --git a/old-strategy.tex b/old-strategy.tex new file mode 100644 index 0000000..da8ff9c --- /dev/null +++ b/old-strategy.tex @@ -0,0 +1,169 @@ + +\section{Planning phase} + +The results of the planning phase consist of: +\begin{itemize*} +\item{ The relation $\hasdirdep$ and hence the partial order $\hasdep$. } +\item{ For each commit set $\pc$, a confirmed set of sources $\set S_{\pc}$. } +\item{ For each commit set $\pc$, the order in which to merge the sources + $E_{\pc,j} \in \set E_{\pc}$. } +\item{ For each $E_{\pc,j}$ an intended merge base $M_{\pc,j}$. } +\end{itemize*} + +We use a recursive planning algorith, recursing over Topbloke commit +sets (ie, sets $\py$ or $\pn$). We'll call the commit set we're +processing at each step $\pc$. +At each recursive step +we make a plan to merge all $\set E_{\pc} = \{ E_{\pc,j \ldots} \}$ +and all the direct contributors of $\pc$ (as determined below) +into $\tipzc$, to make $\tipfc$. + +We start with $\pc = \pl$ where $\pl = \patchof{L}$. + + +\subsection{Direct contributors for $\pc = \pcn$} + +The direct contributors of $\pcn$ are the commit sets corresponding to +the tip branches for the direct dependencies of the patch $\pc$. We +need to calculate what the direct dependencies are going to be. + +Choose an (arbitrary, but ideally somehow optimal in +a way not discussed here) ordering of $\set E_{\pc}$, $E_{\pc,j}$ +($j = 1 \ldots m$). +For brevity we will write $E_j$ for $E_{\pc,j}$. +Remove from that set (and ordering) any $E_j$ which +are $\le$ and $\neq$ some other $E_k$. + +Initially let $\set D_0 = \depsreqof{\tipzc}$. +For each $E_j$ starting with $j=1$ choose a corresponding intended +merge base $M_j$ such that $M_j \le E_j \land M_j \le T_{\pc,j-1}$. +Calculate $\set D_j$ as the 3-way merge of the sets $\set D_{j-1}$ and +$\depsreqof{E_j}$ using as a base $\depsreqof{M_j}$. This will +generate $D_m$ as the putative direct contributors of $\pcn$. + +However, the invocation may give instructions that certain direct +dependencies are definitely to be included, or excluded. As a result +the set of actual direct contributors is some arbitrary set of patches +(strictly, some arbitrary set of Topbloke tip commit sets). + +\subsection{Direct contributors for $\pc = \pcy$} + +The sole direct contributor of $\pcy$ is $\pcn$. + +\subsection{Recursive step} + +For each direct contributor $\p$, we add the edge $\pc \hasdirdep \p$ +and augment the ordering $\hasdep$ accordingly. + +If this would make a cycle in $\hasdep$, we abort . The operation must +then be retried by the user, if desired, but with different or +additional instructions for modifying the direct contributors of some +$\pqn$ involved in the cycle. + +For each such $\p$, after updating $\hasdep$, we recursively make a plan +for $\pc' = \p$. + + + +\section{Execution phase} + +We process commit sets from the bottom up according to the relation +$\hasdep$. For each commit set $\pc$ we construct $\tipfc$ from +$\tipzc$, as planned. By construction, $\hasdep$ has $\patchof{L}$ +as its maximum, so this operation will finish by updating +$\tipca{\patchof{L}}$ with $\tipfa{\patchof{L}}$. + +After we are done with each commit set $\pc$, the +new tip $\tipfc$ has the following properties: +\[ \eqn{Tip Sources}{ + \bigforall_{E_i \in \set E_{\pc}} \tipfc \ge E_i +}\] +\[ \eqn{Tip Dependencies}{ + \bigforall_{\pc \hasdep \p} \tipfc \ge \tipfa \p +}\] +\[ \eqn{Perfect Contents}{ + \tipfc \haspatch \p \equiv \pc \hasdep \py +}\] + +For brevity we will sometimes write $\tipu$ for $\tipuc$, etc. We will start +out with $\tipc = \tipz$, and at each step of the way construct some +$\tipu$ from $\tipc$. The final $\tipu$ becomes $\tipf$. + +\subsection{Preparation} + +Firstly, we will check each $E_i$ for being $\ge \tipc$. If +it is, are we fast forward to $E_i$ +--- formally, $\tipu = \text{max}(\tipc, E_i)$ --- +and drop $E_i$ from the planned ordering. + +Then we will merge the direct contributors and the sources' ends. +This generates more commits $\tipuc \in \pc$, but none in any other +commit set. We maintain +$$ + \bigforall_{\p \isdep \pc} + \pancsof{\tipcc}{\p} \subset + \pancsof{\tipfa \p}{\p} +$$ +\proof{ + For $\tipcc = \tipzc$, $T$ ...WRONG WE NEED $\tipfa \p$ TO BE IN $\set E$ SOMEHOW +} + +\subsection{Merge Contributors for $\pcy$} + +Merge $\pcn$ into $\tipc$. That is, merge with +$L = \tipc, R = \tipfa{\pcn}, M = \baseof{\tipc}$. +to construct $\tipu$. + +Merge conditions: + +Ingredients satisfied by construction. +Tip Merge satisfied by construction. Merge Acyclic follows +from Perfect Contents and $\hasdep$ being acyclic. + +Removal Merge Ends: For $\p = \pc$, $M \nothaspatch \p$; OK. +For $\p \neq \pc$, by Tip Contents, +$M \haspatch \p \equiv L \haspatch \p$, so we need only +worry about $X = R, Y = L$; ie $L \haspatch \p$, +$M = \baseof{L} \haspatch \p$. +By Tip Contents for $L$, $D \le L \equiv D \le M$. OK.~~$\qed$ + +WIP UP TO HERE + +Addition Merge Ends: If $\py \isdep \pcn$, we have already +done the execution phase for $\pcn$ and $\py$. By +Perfect Contents for $\pcn$, $\tipfa \pcn \haspatch \p$ i.e. +$R \haspatch \p$. So we only need to worry about $Y = R = \tipfa \pcn$. +By Tip Dependencies $\tipfa \pcn \ge \tipfa \py$. +And by Tip Sources $\tipfa \py \ge $ + +want to prove $E \le \tipfc$ where $E \in \pendsof{\tipcc}{\py}$ + +$\pancsof{\tipcc}{\py} = $ + + +computed $\tipfa \py$, and by Perfect Contents for $\py$ + + +with $M=M_j, L=T_{\pc,j-1}, R=E_j$, +and calculate what the resulting desired direct dependencies file +(ie, the set of patches $\set D_j$) +would be. Eventually we + +So, formally, we select somehow an order of sources $S_i$. For each + + +Make use of the following recursive algorithm, Plan + + + + + recursively make a plan to merge all $E = \pends$ + +Specifically, in + + + + + + +