Update error message for EnsureWixToolsetInstalled, from @totszwai, requests a different URL in the build-time message that appears when WiX v4 isn't installed. Today, WiX v4 is unstable and shuffled away from the stable WiX v3.11 release. Rob volunteered to take this bug and, perhaps, create a different "landing" URL for WiX v4 builds.
Visual Studio 2017 build server support, from @Matthew-Bonner, reported lack of support for the Visual Studio Build Tools SKU. That is, in fact, sadly true: The Build Tools SKU doesn't support VSIX extensions so we can't install MSBuild targets that redirect to those installed by the WiX build tools.
HEAT5052 when directory contains hardlinks, from @raijinsetsu, reports that Heat.exe doesn't support directory hard links. That's odd so we took the bug in WiX v4.x for someone to investigate the cause.
InstallMessage references Options button even when SuppressOptionsUI="yes", from @tbeattie63, points out that even if you suppress the Options page in WixStdBA, the localized string on the main page still mentions it. We took this issue into WiX v4.0 for someone to investigate adding a second loc string.
WiX projects do not build with dotnet build, from @arturosevilla, reports a problem between the .NET Core build tools and WiX v3.11's MSBuild targets. Rob, lately experimenting with .NET Core in his copious spare time, volunteered to investigate.
LGHT0219: The NUMBER_OF_PROCESSORS environment variable is set to an invalid value, from @khenzar, indicates that on an "Insider" build of Windows 10, the
NUMBER_OF_PROCESSORSenvironment variable, which WiX uses to determine how many threads to use when creating cabs, isn't valid. There's code to handle a missing value but not an invalid one, so we took this issue into WiX v4.x to be more defensive.
XmlConfig failed when target XML file exists but it is empty, from @KonstantinChizhov, reports that the
XmlConfigcustom action doesn't correctly handle XML files that exist but are empty. That does indeed seem to be the case, so we took the bug into WiX v4.x.
Error building simple setup, from @erikread, is another bug report on an Insider build of Windows 10. We asked the reporter to report the bug to the Windows team, as it appears to be a change in behavior in Windows Installer itself.
Heat Project Harvesting does not harvest app.config for DLLs, from @jmairboeck, requests that Heat.exe harvest .config files for DLL projects like it does for EXE projects. A perfectly reasonable request, which we took into WiX v4.x.
Add support for Microsoft MAT for .wxl files, from @wstaelens, is a request that .wxl loc-string files support Microsoft's Multilingual App Toolkit, or, that Multilingual App Toolkit support .wxl files. Either way, we took the request in WiX v4.x if someone would do the investigatory work to determine what's required for that kind of support.
WiX v4.0 baselines
Rob proposed that as a major release, WiX v4.0 should trim the long tail of supported versions of Visual Studio and .NET Framework. So, for example, WiX v4.0 would drop support for Visual Studio versions before 2015 and require .NET Framework 4.6.1 to run the build tools. We believe few people would be impacted and, of course, WiX v3.11 is always ready to handle your older version needs.
I wrote a bit more about these changes on my blog.