[Monotone-devel] Errors when updating a custom command for 0.43

[John Bailey]

Hi, everyone,

One of my fellow Pidgin developers wrote a "pluck-log" command into his
.monotone/monotonerc whose purpose is to pluck a revision or a series of
revisions and grab the original changelog(s) for use in the changelog for the
resulting revision.  His original code was this:

function find_topsrcdir()
    local path = "."
    local f
    while 1 do
        f = io.open(path .. "/_MTN/", "r")
        if f then break end
        path = path .. "/.."
    end
    f:close()
    return path
end

-- pluck-log command
function pluck_log(...)
    local revs = {...}
    topsrcdir = find_topsrcdir()
    local logfile = io.open(topsrcdir .. "/_MTN/log", "r")
    local log = ""
    if logfile then
        log = logfile:read("*all")
        logfile:close()
    end
    table.foreach(revs,
        function (index, rev)
            r, sel = mtn_automate("select", rev)
            if r == false then return end
            for rev in sel:gmatch("%S+") do
                r, certs = mtn_automate("certs", rev)
                certs:gsub("%s+key \"(.-)\"\n%s*signature \"(.-)\"\n%s*name
\"(.-)\"\n%s*value \"(.-)\"\n%s*trust \"(.-)\"",
                        function(key, sig, name, value, trust)
                            if name == "changelog" then
                                log = log .. "*** Plucked rev " ..
string.sub(rev, 0, 8) .. " (" .. key .. "):\n" .. value .. "\n"
                            end
                        end
                    )
                execute("mtn", "pluck", "-r", rev)
            end
        end
    )
    logfile = io.open(topsrcdir .. "/_MTN/log", "w")
    logfile:write(log)
    logfile:close()
end

register_command("pluck-log", "REVISION1 [REVISION2 [...]]", "Pluck a revision
with a good log",
        "This plucks a list of revisions, each individually, and adds the
changelog of each revision for the next commit log." ..
        "\nEXAMPLE:\tmtn pluck-log h:im.pidgin.pidgin deadbeef\n",
        "pluck_log")

As it is, this code worked.  However, knowing that 'mtn automate
get_workspace_root' exists in mtn 0.43 and newer, I set out to update the
command to take advantage of the new automate feature.  My revised code drops
the find_topsrcdir function in favor of mtn_automate.  I also removed the
trimming of the revision ID, thus causing the entire revision ID to be printed
instead of just the first 8 digits.  The new code looks like this:

-- pluck-log command
function pluck_log(...)
    local revs = {...}
    local result,topsrcdir = mtn_automate("get_workspace_root")
    local logfile = io.open(topsrcdir .. "/_MTN/log", "r")
    local log = ""
    if logfile then
        log = logfile:read("*all")
        logfile:close()
    end
    table.foreach(revs,
        function (index, rev)
            r, sel = mtn_automate("select", rev)
            if r == false then return end
            for rev in sel:gmatch("%S+") do
                r, certs = mtn_automate("certs", rev)
                certs:gsub("%s+key \"(.-)\"\n%s*signature \"(.-)\"\n%s*name
\"(.-)\"\n%s*value \"(.-)\"\n%s*trust \"(.-)\"",
                        function(key, sig, name, value, trust)
                            if name == "changelog" then
                                log = log .. "*** Plucked rev " .. rev .. " ("
.. key .. "):\n" .. value .. "\n"
                            end
                        end
                    )
                execute("mtn", "pluck", "-r", rev)
            end
        end
    )
    logfile = io.open(topsrcdir .. "/_MTN/log", "w")
    logfile:write(log)
    logfile:close()
end

register_command("pluck-log", "REVISION1 [REVISION2 [...]]", "Pluck a revision
with a good log",
        "This plucks a list of revisions, each individually, and adds the
changelog of each revision for the next commit log." ..
        "\nEXAMPLE:\tmtn pluck-log h:im.pidgin.pidgin deadbeef\n",
        "pluck_log")

However, when I use the updated pluck-log command, I get the following error:

>>$ mtn pluck-log 074c5aedf9bbc512331f0d3130f076190b290676
mtn: [left]  61175582f54c5b32f2896ecaddeede75a1bae0f8
mtn: [right] 074c5aedf9bbc512331f0d3130f076190b290676
mtn: modifying libpurple/protocols/yahoo/yahoo.h
mtn: applied changes to workspace
mtn: warning: /home/jbailey/.monotone/monotonerc:48: attempt to index local
'logfile' (a nil value)
mtn: misuse: Call to user command pluck-log (lua command: pluck_log) failed.

In my monotonerc, line 48 is the second io.open in the new code shown.

To put to rest the obvious first question:
>>$ mtn --version
monotone 0.43 (base revision: ddc6546051abf6475c40a3fdba272e2f82a40e94)

Any insight would be greatly appreciated.

Thanks,
John

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