Two MSI installers where each adds its folder if the other is already installed

[gaetandezeiraud]

I have a Windows application that installs a common program along with two optional data folders:

• Data/FolderA
• Data/FolderB

I want to create two separate MSI packages:
1- MyApp-FolderA.msi -> installs the app + FolderA
2- MyApp-FolderB.msi -> installs the app + FolderB

The desired behavior is:

• Installing one MSI installs its associated folder and program (same program).
• If the other folder is already installed by the other MSI, it should remain intact but add the FolderA / B accordingly.
• On upgrade, whichever MSI is run should update all installed folders, regardless of which installer originally installed them. If FolderA exist, it update it, if both, it update both, etc... So both folders are needed in each msi.
• All of this should happen using only MSI logic, without the Wix boostrapper.

My question: Is it possible to achieve this "additive install" behavior with two separate MSI installers using standard Windows Installer features?

If not, what is the recommended MSI-compliant way to achieve this kind of scenario? If exist...

Thank you!

[robmen]

Yes, this is supported by the Windows Installer. Sharing requires more discipline, but the Windows Installer is one of the few installation technologies that bothered to make it work. 😄

[gaetandezeiraud]

I think I understand what you’re aiming for. I should install both folders whereas the MSI (A or B).

And my problematic now is: I "just" need to figure out how to create different desktop shortcuts, since I rely heavily on them. Each shortcut uses "--data=FolderA/B" to determine which instance to load.

So if MSIA is installed I have shortcut A. If later the user install B, FolderB is already there, so I only have to create the associated shortcut.

Question is about uninstalling now, but I think I can find something to delete both if exist.

[chrpai]

I need a more information to give advice. It depends on how many users, locations, distribution methods and current pain points. I assume the data in A and B isn't sensitive since your willing to include it in both installers.

I offer consulting services. I'd be happy to spend a free hour on a screen share discussing the issue and creating a minimalist POC to test out the user experience.

[chrpai]

As I think about this, the biggest challenge to address is versioning rules. On two levels:

1. If A 1.0 is installed and B 2.0 is installed A will really be 2.0 not 1.0 as described by Add/Remove Programs
2. If B 2.0 is installed (with FolderB files) and A 1.0 is then installed ....what to do with overwriting or not overwriting FolderA files. You might need a versioned keyfile to influence this.

Either way there's actually a lot of complexity and testing here. It can be done but really I'd explore various ways to refactor the app a bit to keep it more vanilla.

[gaetandezeiraud]

Thank you. I don't think it is complexe for this case? But maybe I missing something. MSIA and MSIB have both the app, FolderA and FolderB. So, in theory (yeah only yet), if the MSIB is installed, it also update the FolderA by checking if he exist.

It's how we do with Installshield currently. It naive but works.

[chrpai]

What percentage of users install A, B and A+B? Why was this design choosen?

It's really hard for me to ask the right questions without knowing more about the product. I do think it's complex. We wouldn't be having this conversation if it wasn't. :)

[chrpai]

I'm trying to understand your scenario. You say the app and both folders have to be in both MSI so how are the MSI different?

I'd have to dive deeper into your app design/behavior but I suspect there might be ways to simplify this and still achieve your goals.

[gaetandezeiraud]

Thank you.

Yes, FolderA and FolderB need to be in both msi in the case of an upgrade. If the two are already installed by the user (MSI_A and then MSI_B), I need a way to update both.

Currently, I use Installshield for this scenario. But the team want to migrate to msi. And it's a bit harder...

It's an industrial software. With 2 data variants depending the activity sector.

So, clients can install only A, only B or both. But they don't want this to be a feature selection. But different "physical" msi.

Not sure if it is clear. Let's me know.

[gaetandezeiraud]

But if you have suggestions, I take it! I tried without success for the moment to play with "features" for FolderA and FolderB. But when MsiB is installed, I thinks the previous choice is saved somewhere and it doesn't install the FolderB. Not easy!