fetch: declare command using decorator

extdiff: declare command using decorator

churn: declare command using decorator

convert: declare commands using decorator

debugshell: declare command using decorator

largefiles: declare commands using decorator

cmdutil: omit redundant "savecommitmessage()" in "tryimportone()" The preceding patch causes that "makememctx()" with "editor" argument saves (manually edited) commit message into ".hg/last-message.txt": saving itself is executed indirectly in "memctx.__init__()". This makes it redundant to invoke "savecommitmessage()" on caller side of "makememctx()". This patch omits such redundant "savecommitmessage()" invocation in "tryimportone()". "tryimportone()" uses one of "commiteditor" or "commitforceeditor" as "editor" argument, and this causes saving commit message always.

amend: use "editor" argument for "memctx.__init__" to save commit message This patch uses "editor" argument of "memctx.__init__" to save commit message, instead of explicit editor invocation and saving commit message by "localrepository.savecommitmessage()". By passing one of "commiteditor" or "commitforceeditor" as "editor", "memctx.__init__" saves commit message, even when editor invocation is not needed.

histedit: pass "editor" argument to "memctx.__init__()" for "collapse" command The preceding patch causes that "memctx.__init__()" with "editor" argument invokes editor and saves edited commit message into ".hg/last-message.txt". This patch passes "editor" argument to "memctx.__init__()" instead of explicit invocations of "commitforceeditor()" and "savecommitmessage()" for "collapse" command.

context: move editor invocation from "makememctx()" to "memctx.__init__()" This patch introduces "editor" argument to "memctx.__init__()", and moves editor invocation from "makememctx()" to "memctx.__init__()", to centralize editor invocation into "memctx" object creation. This relocation is needed, because "makememctx()" requires the "store" object providing "getfile()" to create "memfilectx" object, and this prevents some code paths from using "makememctx()" instead of "memctx.__init__()". This patch also invokes "localrepository.savecommitmessage()", when "editor" is specified explicitly, to centralize saving commit message into "memctx" object creation: passing "cmdutil.commiteditor" as "editor" can achieve both suppressing editor invocation and saving into ".hg/last-message.txt" for non empty commit messages.