Windows Installer does not broadcast a WM_SETTINGCHANGE

[mathiask88]

Hi,

if I install io.js with the MSI the PATH changes do not take effect until restart/logout-login. This can be fixed if the MSI broadcasts a WM_SETTINGCHANGE message with lParam set to Environment. Anyone else with this problem? Maybe my windows is just broken :)

[piscisaureus]

if I install io.js with the MSI the PATH changes do not take effect until restart/logout-login.

I have heard other people say the same but I've never been able to reproduce the issue.
For me it's always enough to open a new console window. I've tested this with various windows versions (XP, 7, 8.1).

This can be fixed if the MSI broadcasts a WM_SETTINGCHANGE message with lParam set to Environment.

I am not sure this is true. I don't think it has any effect on the scenario where the command window is re-opened after installation. Also, cmd.exe does not listen for WM_SETTINGCHANGE.

The installer source code is here: https://github.com/iojs/io.js/blob/v1.x/tools/msvs/msi/product.wxs
Feel free to poke around and see if you can fix the issue; improvements are welcome.

[mathiask88]

I'm on Windows 8.1 x64 and if I run the cmd after installation as administrator the PATH is updated correct, but not in a non-administrator cmd (Maybe you have UAC disabled?) And I wrote a small console application that broadcasts the WM_SETTINGCHANGE message and then it was enough to open a new cmd as you said. Right the cmd.exe does not listen, but the explorer.exe does and is responsible for that behavior.

[piscisaureus]

I'm on Windows 8.1 x64 and if I run the cmd after installation as administrator the PATH is updated correct, but not in a non-administrator cmd (Maybe you have UAC disabled?)

I'm using windows 8.1 too; whether I run elevated or non-elevated cmd.exe doesn't seem to matter here. (Slightly OT, I believe that in Windows 8.1 it's not really possible to turn UAC off. The only option you have is to not show the UAC popup).

And I wrote a small console application that broadcasts the WM_SETTINGCHANGE message and then it was enough to open a new cmd as you said. Right the cmd.exe does not listen, but the explorer.exe does and is responsible for that behavior.

I'll take your word for it. Is it possible to modify the installer so it broadcasts this message?

[piscisaureus]

See also nodejs/node-v0.x-archive#2407

[mathiask88]

Ok, if I reboot and run the MSI it works as expected, but if I uninstall and then install io.js again then the same behavior occurs. So in my case I removed node.js before I installed io.js and the node.js MSI set something like a "restart pending" flag and io.js MSI did not broadcast... But none of the installers say that a reboot IS necessary!

The usual restart pending registry keys that I know are HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\UpdateExeVolatile and HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\PendingFileRenameOperations that not exist on my system.

I think if a reboot is not necessary then the MSI should not behave like this. But overall this is a rare case. Thanks @piscisaureus for your fast response!

[mathiask88]

I referenced a fix. Now the installer always sends a WM_SETTINGCHANGE, even if you install and uninstall any number of times without rebooting/relogin. If you want to change the behavior I can create a PR.

[rvagg]

Wow, that's crazy...

We could merge this and try it out in nightlies before committing to a release with this. If you don't get a quick -1 here @mathiask88 then you should PR this.

[mathiask88]

@rvagg indeed, however it would be nice if someone could reproduce this.

[piscisaureus]

@mathiask88 @rvagg

My suggestion would be to land that patch asap and ship it as part of a release to see if there is any fallout.
It's quite messy and doesn't conform to our code style, but I couldn't spot any bugs. I think it'd be good to see how well it fares in practice, and clean up later if it sticks.

[piscisaureus]

... But none of the installers say that a reboot IS necessary!

That may be because we didn't define a dialog in which this shown.

[mathiask88]

@piscisaureus Yes, this was a quick fix and I did not look into your code styles yet. I am not a professional , but I will do my best and try to match your styles and open a PR.

... But none of the installers say that a reboot IS necessary!

That may be because we didn't define a dialog in which this shown.

I ran the io.js MSI in verbose mode and the logfile did not contain any MsiSystemRebootPending property. So after all I really don't know why the WriteEnvironmentStrings only updates for the first setup. Even if I am not happy with this patch it fixes the issue.