createmarkers: automatically record the parent of pruned changesets We need this information to build the set of relevant markers during exchanges. This can only be done at the `createmarkers` level since the `obsstore.create` function does not have a repo and therefore has no access to the parent information.

obsstore: add a `parents` argument to obsstore.create We need a way to pass the information to the function. Some guru told me that what's arguments are made for.

obsstore: add a `parents` field This field is intended to store the parent of the precursor. This is useful to attach pruned changesets to a set of exchanged changesets. We currently just add the fields with a None value. None stands for "no data recorded".

obsstore: add some documentation about the marker fields As the number of fields grow, it makes sense to start documenting their contents.

transplant: change "editform" to distinguish merge commits from others "editform" argument for "getcommiteditor" is decided according to the format below: EXTENSION[.COMMAND][.ROUTE] - EXTENSION: name of extension - COMMAND: name of command, if there are two or more commands in EXTENSION - ROUTE: name of route, if there are two or more routes in COMMAND This patch newly adds "normal" and "merge" as ROUTE, to distinguish merge commits from other. This patch adds 4 test patterns to test combination of "merge"(x2) and "--continue"(x2).

rebase: change "editform" to distinguish merge commits from others "editform" argument for "getcommiteditor" is decided according to the format below: EXTENSION[.COMMAND][.ROUTE] - EXTENSION: name of extension - COMMAND: name of command, if there are two or more commands in EXTENSION - ROUTE: name of route, if there are two or more routes in COMMAND This patch newly adds "merge" as ROUTE, to distinguish merge commits from other. This patch passes bool as "ctxorbool" to "mergeeditform", because working context has always 2 parents at this point. Dropping the second parent of non-merging commits is executed in "concludenode". Unlike other patches in this series (e.g. for "hg commit"), this patch doesn't add "normal.normal"/"normal.merge" style ROUTEs, because there is no "merge" case in "collapse" ROUTE.

import: change "editform" to distinguish merge commits from others "editform" argument for "getcommiteditor" is decided according to the format below: COMMAND[.ROUTE] - COMMAND: name of command - ROUTE: name of route, if there are two or more routes in COMMAND This patch uses "normal.normal" and "normal.merge" as ROUTE of "editform" instead of "normal", to distinguish merge commits from other in "hg import" without "--bypass" case. This patch assumes "editform" variations for "hg import" below: import.normal.normal import.normal.merge import.bypass.normal import.bypass.merge Unlike other patches in this series, this patch uses "editor.sh" instead of "checkeditform.sh" for the name of the script to check "HGEDITFORM", because it has to do more than checking "HGEDITFORM". To invoke editor forcibly in "test-import-merge.t", this patch creates the patch not having patch description as "merge.nomsg.diff".