Paket 5.214.0 gives 'error MSB4086: A numeric comparison was attempted...'

[aklefdal]

Description

Paket 5.214.0 seems to have broken our build (restore), but only on the build server. Gets the following error message:

.paket\Paket.Restore.targets(77,169): error MSB4086: A numeric comparison was attempted on "$(MSBuildVersion)" that evaluates to "" instead of a number, in condition " '$(MSBuildVersion)' < '16.0.360' ".

Repro steps

1. Have a solution that works fine yesterday. Using Paket for dependencies, and Fake 5.15.1 or 5.15.2 for build scripts.
2. Run a build after 5.214 is released

The builds scripts work fine on my machine, which has VS2019 installed. It works even in a standard command prompt. On the build agent, with .Net 4.7.2 developer pack installed, it fails.

Expected behavior

A working build.

Actual behavior

From the build log:

[Restore] PaketRestore: task: .
[12:14:51] : [PaketRestore] .> "C:\BuildAgent\work\7bdd66bf3bac5843.paket\paket.exe" restore (In: false, Out: false, Err: false)
[12:14:51] : [PaketRestore] Paket version 5.214.0
[12:14:51] : [PaketRestore] The last restore is still up to date. Nothing left to do.
[12:14:51] : [PaketRestore] Performance:
[12:14:51] : [PaketRestore] - Runtime: 142 milliseconds
[12:14:51]E: [Step 1/3] Build: target
[12:14:51]E: [Build] MSBuild: task: C:\BuildAgent\work\7bdd66bf3bac5843\src\MYPROJECT\MYPROJECT.csproj
[12:14:51] : [MSBuild] C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\MSBuild.exe "C:\BuildAgent\work\7bdd66bf3bac5843\src\MYPROJECT\MYPROJECT.csproj" /t:Build /m /nodeReuse:False /v:m /clp:ForceConsoleColor /p:RestorePackages=True /p:OutputPath=C:%5CBuildAgent%5Cwork%5C7bdd66bf3bac5843%5Cbuild%5Cradio%5C /p:Configuration=Release "/bl:C:\BuildAgent\temp\buildTmp\tmp5924.tmp.binlog"
[12:14:51] : [MSBuild] C:\BuildAgent\work\7bdd66bf3bac5843> "C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\MSBuild.exe" "C:\BuildAgent\work\7bdd66bf3bac5843\src\MYPROJECT\MYPROJECT.csproj" /t:Build /m /nodeReuse:False /v:m /clp:ForceConsoleColor /p:RestorePackages=True /p:OutputPath=C:%5CBuildAgent%5Cwork%5C7bdd66bf3bac5843%5Cbuild%5Cradio%5C /p:Configuration=Release "/bl:C:\BuildAgent\temp\buildTmp\tmp5924.tmp.binlog" (In: false, Out: false, Err: false)
[12:14:51] : [MSBuild] Microsoft (R) Build Engine version 15.5.180.51428 for .NET Framework
[12:14:51] : [MSBuild] Copyright (C) Microsoft Corporation. All rights reserved.
[12:14:51] : [MSBuild]
[12:14:51] : [MSBuild] C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\MSBuild.exe /bl:C:\BuildAgent\temp\buildTmp\tmp5924.tmp.binlog /clp:ForceConsoleColor /m /nodeReuse:False /p:RestorePackages=True /p:OutputPath=C:%5CBuildAgent%5Cwork%5C7bdd66bf3bac5843%5Cbuild%5Cradio%5C /p:Configuration=Release /t:Build /v:m C:\BuildAgent\work\7bdd66bf3bac5843\src\MYPROJECT\MYPROJECT.csproj
[12:14:51] : [MSBuild] [31;1mC:\BuildAgent\work\7bdd66bf3bac5843.paket\Paket.Restore.targets(77,169): error MSB4086: A numeric comparison was attempted on "$(MSBuildVersion)" that evaluates to "" instead of a number, in condition " '$(MSBuildVersion)' < '16.0.360' ". [C:\BuildAgent\work\7bdd66bf3bac5843\src\MYPROJECT\MYPROJECT.csproj]
[12:14:51] : [MSBuild] [m
[12:14:51]E: [MSBuild] : C:\BuildAgent\work\7bdd66bf3bac5843.paket\Paket.Restore.targets(77,169): error MSB4086: A numeric comparison was attempted on "$(MSBuildVersion)" that evaluates to "" instead of a number, in condition " '$(MSBuildVersion)' < '16.0.360' ".

Known workarounds

Project files are the new SDK format, upgraded a few weeks ago, so we could now upgrade the build script to use Dotnet CLI instead.

[aklefdal]

I can confirm that using Dotnet Cli instead of Msbuild directly is a working solution for us.

[matthid]

@aklefdal I guess the VS2017 on the build server is not up to date but some older version?

[matthid]

If you want to test a fix (or have a workaround):

• Download Paket.Restore.targets from This PR
• Replace .paket/Paket.Restore.targets in your repository
• Set the PAKET_SKIP_RESTORE_TARGETS environment variable to true in your CI/locally (in order for Paket/Fake to not replace that file)
• Re-run the build

Otherwise wait for the PR to be released and report back.

[forki]

can you please retry with 5.215.0?

[aklefdal]

I retried this morning, and can confirm that Paket 5.215 (with FAKE 5.15.3) works. You guys rock!

I will have a look at the instalment of build tools on the build agents, you are right, they might be outdated.

[08:40:23] : [MSBuild] [36;1m 3:2> [m [36;1mProject "C:\BuildAgent\work\7bdd66bf3bac5843\src\MYPROJECT\MYPROJECT.csproj" (3:2) is building "C:\BuildAgent\work\7bdd66bf3bac5843\src\MYOTHERPROJECT\MYOTHERPROJECT.csproj" (12:2) on node 1 (_GenerateRestoreProjectPathWalk target(s)).
[08:40:23] : [MSBuild] [m [36;1m 12> [m [33;1mC:\BuildAgent\work\7bdd66bf3bac5843.paket\Paket.Restore.targets(134,5): warning : This version of MSBuild (we assume '15.0.0' or older) doesn't support GetFileHash, so paket fast restore is disabled. [C:\BuildAgent\work\7bdd66bf3bac5843\src\MYOTHERPROJECT\MYOTHERPROJECT.csproj]
[08:40:23] : [MSBuild] [m "C:\BuildAgent\work\7bdd66bf3bac5843.paket\paket.exe" restore
[08:40:23] : [MSBuild] Paket version 5.215.0
[08:40:23] : [MSBuild] The last restore is still up to date. Nothing left to do.
[08:40:23] : [MSBuild] Performance:
[08:40:23] : [MSBuild] - Runtime: 139 milliseconds