338878 - Only one install of AccessibleMarshal.dll can be registered at a time which can lead to it being unregistered

Status: NEW

(Core :: Disability Access APIs, defect)

Description

[Robert Strong (they/them - no direct email)]

Only one install of AccessibleMarshal.dll can be registered even though there are multiple copies of it installed. This can lead to an older or newer version being used when compared to the app using it. When an app is uninstalled it will be unregistered even though there are other apps that use it.

Comment 1

[Aaron Leventhal]

True, how should we fix that? It's how COM Marshalling DLL's are. You can only register one of them afaik.

Comment 2

[Robert Strong (they/them - no direct email)]

hmmm... I brought this up to bsmedberg. Perhaps he has an idea.

Comment 3

[Robert Strong (they/them - no direct email)]

If it is desired I can add a workaround for this bug - the uninstaller could check if there is another install of a Mozilla product by enumerating the reg and if the AccessibleMarshal.dll exists register it. Is it worth it?

Comment 4

[Aaron Leventhal]

(In reply to comment #3)
> If it is desired I can add a workaround for this bug - the uninstaller could
> check if there is another install of a Mozilla product by enumerating the reg
> and if the AccessibleMarshal.dll exists register it. Is it worth it?

Is that a workaround or a real fix? Doesn't sound bad. What are our other options?

Comment 5

[Robert Strong (they/them - no direct email)]

It is a workaround in my opinion that should work in most cases. A real fix would be to have a single copy of AccessibleMarshal.dll installed / registered somewhere under Program Files\Common Files\ that all apps would use and of course would need to be compatible with all apps no matter the version of the app / dll combination which is to say the least tricky... hence the term dll hell. I suppose another option would be to have unique registrations but I am unfamiliar with what this dll provides.

Comment 6

[Aaron Leventhal]

(In reply to comment #5)
I would of course love to see the real fix. Maybe there is some example code somewhere out (with a compatible license) that we could take a look at or utilize.

The temporary workaround is also very welcome. May I assign the bug to you for now?

Comment 7

[Aaron Leventhal]

Surkov, if you figure out a solution to this I'd be grateful.

Comment 8

[Marco Zehe (:MarcoZ)]

Do we still need to do anything here? I've never heard any  complaints or support issues that would have resulted from the marshalling DLL being inadvertently unregistered. WONTFIX?

Comment 9

[Robert Strong (they/them - no direct email)]

Without it registered the functionality won't be present so even without complaints or support issues this is still a valid bug.

Comment 10

[David Bolter [:davidb] (NeedInfo me for attention)]

Jamie, Mick what do you guys think? We have a proposed workaround in comment 3 and additional ideas in comment 5.

Comment 11

[James Teh [:Jamie]]

Assuming there's some way to check the reference count on a shared dll (or at least whether it should be removed yet), bug 606393 should fix this.

Comment 12

[James Teh [:Jamie]]

(In reply to James Teh [:Jamie] from comment #11)
> Assuming there's some way to check the reference count on a shared dll (or
> at least whether it should be removed yet)
There is. If you're using the NSIS InstallLib and UninstallLib macros:
http://nsis.sourceforge.net/Docs/AppendixB.html
this will be handled automatically. Otherwise, you can query/update the ref count in the registry: HKLM\Software\Microsoft\Windows\CurrentVersion\SharedDLLs

Comment 13

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee is inactive on Bugzilla, so the assignee is being reset.