DisableImplicitNamespaceImports=false doesn't disable DisableImplicitNamespaceImports_DotNet.

[safern]

When settings DisableImplicitNamespaceImports=false, DisableImplicitNamespaceImports_DotNet is not set to any value:

sdk/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.GenerateImplicitNamespaceImports.targets

Line 22 in 2c47826

<DisableImplicitNamespaceImports_DotNet Condition="'$(DisableImplicitNamespaceImports_DotNet)' == '' and '$(DisableImplicitNamespaceImports)' != 'true'">false</DisableImplicitNamespaceImports_DotNet>

So this condition '$(DisableImplicitNamespaceImports_DotNet)'!='true' in

sdk/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.DefaultItems.props

Line 86 in 2c47826

<ItemGroup Condition=" '$(DisableImplicitNamespaceImports_DotNet)' != 'true'

is true and the implicit namespaces are still generated. So the only way to disable them is to set both properties to true explicitly.

cc: @dsplaisted @JunTaoLuo

[safern]

I think this applies to all DisableImplicitNamespaceImports_* variations.

[JunTaoLuo]

That's strange, DisableImplicitNamespaceImports controls the entire target:

sdk/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.GenerateImplicitNamespaceImports.targets

Line 38 in 2c47826

Condition="'$(DisableImplicitNamespaceImports)' != 'true'" />

.

The individual conditions do not control whether the target runs or not, they only control whether the namespaces are added to the item group that's used by the target.

In effect, DisableImplicitNamespaceImports controls whether the entire feature is turned on or off and DisableImplicitNamespaceImports_DotNet is used to include subsets of namespaces. Is this not the behaviour?

[safern]

I see, this behavior happens with a VB project, the reason for that seems like the vb task uses an item call Import to define the global Imports so that is why we are seeing this in dotnet/runtime when building a vbproj even though the feature is disabled.

[safern]

This is what is causing that behavior:

sdk/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.DefaultItems.props

Lines 85 to 99 in 55195f3

	<!-- Implicit imports -->
	<ItemGroup Condition=" '$(DisableImplicitNamespaceImports_DotNet)' != 'true'
	and '$(TargetFrameworkIdentifier)' == '.NETCoreApp'
	and $([MSBuild]::VersionGreaterThanOrEquals($(_TargetFrameworkVersionWithoutV), '6.0'))">
	<!-- Imports already defined as VB implicit imports are conditioned to not be added twice -->
	<Import Include="System" Condition="'$(Language)' != 'VB'" />
	<Import Include="System.Collections.Generic" Condition="'$(Language)' != 'VB'" />
	<Import Include="System.IO" />
	<Import Include="System.Linq" Condition="'$(Language)' != 'VB'" />
	<Import Include="System.Net.Http" />
	<Import Include="System.Threading" />
	<Import Include="System.Threading.Tasks" Condition="'$(Language)' != 'VB'" />
	</ItemGroup>

Should the ones that are imported for VB be conditioned to not be included if DisableImplicitNamespaceImports=true?

[dougbu]

Reassigning to you @rafikiassumani-msft to ensure this is handled appropriately.

@safern @DamianEdwards is this issue still applicable❔

[DamianEdwards]

As part of the changes in rc.1 the sub-level properties were removed so this doesn't apply anymore.