Numeric comparison: 9 < 10 but 16.9 > 16.10

[AArnott]

Issue Description

MSBuild seems to recognize integers when using inequality operators with string operands (which is good), but it fails to recognize floating point numbers as numeric, instead treating them like ordinary strings. This leads to unexpected evaluation of the conditionals.

As shown in the repro steps, MSBuild recognizes that 9 < 10, but fails to recognize that 16.9 < 16.10. It does recognize 4-component versions though, recognizing that 16.9.0.0 < 16.10.0.0.

Steps to Reproduce

  <Target Name="versiontest">
    <Message Importance="high" Text="'9' &lt;= '10' " />
    <Message Importance="high" Condition="'9' &lt;= '10' " Text="true" />

    <Message Importance="high" Text="'16.9' &lt;= '16.10' " />
    <Message Importance="high" Condition="'16.9' &lt;= '16.10' " Text="true" />

    <Message Importance="high" Text="'16.9.0.0' &lt;= '16.10.0.0' " />
    <Message Importance="high" Condition="'16.9.0.0' &lt;= '16.10.0.0' " Text="true" />
  </Target>

Expected Behavior

  '9' <= '10'
  true
  '16.9' <= '16.10'
  true
  '16.9.0.0' <= '16.10.0.0'
  true

Actual Behavior

  '9' <= '10'
  true
  '16.9' <= '16.10'
  '16.9.0.0' <= '16.10.0.0'
  true

[Forgind]

But 16.9 is greater than 16.1...

I'm more surprised by the four-part version being successfully recognized. I thought we had special property functions to deal with that, but apparently it sees them as versions anyway.

I'd honestly say this is exactly what I'd expect. If you want to compare versions (and have 16.9 be less than 16.10), you can use the version comparison functions.

[AArnott]

you can use the version comparison functions.

What are these "version comparison functions"?
For now I am working around it by artificially adding .0.0 to the end of my floating point numbers.

[Forgind]

See #4911
So it would look like:
<Message Importance="high" Condition="$([MSBuild]::VersionLessThanOrEquals('16.9', '16.10'))" Text="true" />

[AArnott]

@rainersigwald Was this fixed or closed as won't fix? The PR that @Forgind linked to above doesn't address this.

[AArnott]

FWIW @Forgind's PR does provide a workaround that's acceptable. This issue just represents the unintuitive experience when you don't know about those property functions where msbuild recognizes integers and a.b.c.d versions automatically but doesn't recognize floating point numbers. So while IMO this would ideally be fixed, I'm not blocked and you can Won't Fix if you want.

[rainersigwald]

The thing is there's code to do floating point numbers:

msbuild/src/Build/Evaluation/Conditionals/GreaterThanExpressionNode.cs

Lines 20 to 23 in 1c045cf

	protected override bool Compare(double left, double right)
	{
	return left > right;
	}

So if it's not being used that's a problem.