为什么这个简单的applescript在ML mail.app中不再起作用（通常）

Question

It works only when you right click on the mail message and choose "run rules", but not on incoming messages (without interaction).

The first dialog is shown both when incoming or running manually, but the second dialog (with the id) is only shown when running manually. Nothing is shown in console.log

Any ideas?

using terms from application "Mail"
    on perform mail action with messages theMessages for rule theRule
        tell application "Mail"
            repeat with theMessage in theMessages
                display dialog "inside"

                set theId to id of theMessage

                display dialog "the id is " & theId

            end repeat
        end tell
    end perform mail action with messages
end using terms from

update: i added a try catch block around

set theId to id of theMessage

and this is the error I get:

Can't get class mssg 1 of class mbxp "Incoming POP messages" of class mact "Telenet". Invalid index. -1719

Any idea what this means? I don't get the error when applying rules manually.

Update 2: OK i found out that incoming messages don't have an ID yet. That's a problem since I want to save the email to disk:

set theEmail to (do shell script "mdfind -onlyin ~/Library/Mail \"kMDItemFSName = '" & theId & ".emlx'\"")
set archiveName to theId & "-" & (extract address from theMessage's sender) & ".emlx"
set saveLocation to "Users:wesley:Documents:Incoming:"

do shell script "cp '" & theEmail & "' '" & POSIX path of saveLocation & "';"

Is there any way around this?

Answer 1

As promised in my comment , here's an AppleScript that logs Mail messages' subject , id , and message id to ~/Desktop/log.txt.

using terms from application "Mail"
    on perform mail action with messages theMessages for rule theRule
        try
            repeat with theMessage in theMessages
                LogText("subject:    " & (theMessage's subject as string))
                LogText("id:         " & (theMessage's id as string))
                LogText("message id: " & (theMessage's message id as string))
                LogText("")
            end repeat
        on error errorText number errorNumber
            tell application "Mail" to display alert ("Error: " & errorNumber) message errorText
            return
        end try
    end perform mail action with messages
end using terms from


on LogText(theText)
    tell application "Finder"
        set logPath to (path to the desktop as text) & "log.txt"
        try
            set writeText to open for access file logPath with write permission
            set currentDateAsString to do shell script "date +\"%Y-%m-%d %T\""
            write (currentDateAsString & "    " & (theText as text) & return) to writeText starting at ((get eof writeText) + 1)
            close access writeText
        on error errorText number errorNumber
            close access writeText
            error errorText number errorNumber
        end try
    end tell
end LogText

I'm also running OS X 10.8.2 and Mail 6.2. As I said, I'm surprised to say this, but triggering the above AppleScript via mail rule works just as well for incoming messages as it does when selecting the menu "Apply Rules".