[Bug 8243] New: Feature: Add MsiBreak to aid debugging custom actions

[Wine Bugs]

http://bugs.winehq.org/show_bug.cgi?id=8243

Summary: Feature: Add MsiBreak to aid debugging custom actions
           Product: Wine
           Version: 0.9.35.
          Platform: All
        OS/Version: All
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: wine-msi
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Hello,

it seems debugging brain damaged msi installers (hello adobe) became some sort
of daily work :)
There is one incredibly useful "developer" feature missing from wine msi:
"MsiBreak".
Windows msi has this (rather undocumented) feature for some time now to aid
developers to debug custom action dlls/function calls.
Without that you would have to attach to right msi service process (usually the
wrong one), break on "module load" events, set breakpoint on custom action
exports and the like.
Due to constant custom action dll loading/unloading this is a very nasty setup.
That's why the "MsiBreak" feature exists.

Basically it's an environment variable called "MsiBreak" which holds the name of
custom action as value.
If defined and matching the current custom action to be called, msi would ask
the developer to take action.

The developer can attach a debugger to appropriate pid (as displayed in dialog)
and then press "OK".
Msi DebugBreaks() then, allowing the developer to step into custom action code.
If not wanted, one can press "Cancel" ("Cancel" is not in windows version, i
added it as comfort).
The environment variable is read at run time.
Undefining or redefining the current custom action while running the installer
works of course.

I wrote a patch to include this feature to custom msi.
I rarely use winedbg but a custom windows usermode debugger which needs windows
process ids for attach, thats why both process ids are displayed (upid=unix,
wpid=wine/windows).

Regards