Make $(Architecture) initialization resilient against pre-set values in $env

[vatsan-madhavan]

See cmderdev/cmder#2290 for details.

I was building dotnet/wpf just now and noticed that it had trouble building correctly.

I debugged it down to these lines that fail to initialize the MSBuild property $(Architecture) correctly (it's initialized to 64 instead of x64), which in turn lead to my (dev) build failures in dotnet/wpf.

    <Architecture Condition="'$(Platform)'=='x64' or '$(Platform)'=='x86' or '$(Platform)'=='arm' or '$(Platform)'=='arm64'">$(Platform)</Architecture>
    <Architecture Condition="'$(Platform)'=='Win32'">x86</Architecture>
    <Architecture Condition="'$(Architecture)'==''">x64</Architecture>

cmder sets $env:architecture to values like 32, 64, which confuses this logic.

https://github.com/cmderdev/cmder/blob/1071221468f2f75f2b63e482deab69c9ca986219/vendor/init.bat#L125-L132

:: Pick right version of clink
if "%PROCESSOR_ARCHITECTURE%"=="x86" (
    set architecture=86
    set architecture_bits=32
) else (
    set architecture=64
    set architecture_bits=64
)

This only affects dev-builds, and only on some alternate-consoles. Still the fix is trivial and we can make this logic a bit resilient.

[miloush]

Wouldn't it be more proper to fix the offending consoles rather than normalizing non-standard practices?

[vatsan-madhavan]

Absolutely! (BTW cmder has already fixed this based on my report - cmderdev/cmder#2294)

That said, it assumes that the offending console is doing something unequivocally wrong. There is no universal compact on the valid values for an environment variable named architecture, unfortunately. For e.g., a console could have set it legitimately to something like amd64, which was quite commonplace before Intel jumped into the game and x64 became the new norm. and $(Architecture)=amd64 would still trigger the same problem on our side.

There is a subtle bug here, which is this: We don't rule out invalid values that we are incapable of dealing with further down the line. I had assumed at the time I built this that $(Architecture) would only be supplied by the build scripts (if they are supplied by an external party at all), and that the values supplied would only be valid ones.

What we need here is a validity check, and possibly also a check for amd64.

    <!-- 
        Architecture is intended to be driven entirely by $(Platform) - clear it first before proceeding
        to infer its value again in case it has been set externally by the environment or supplied as a 
        parameter to MSBuild 
    -->
    <Architecture/>
    <Architecture Condition="'$(Platform)'=='x64' or 
                             '$(Platform)'=='x86' or 
                             '$(Platform)'=='arm' or 
                             '$(Platform)'=='arm64'">$(Platform)</Architecture>

    <Architecture Condition="'$(Platform)'=='Win32' Or 
                             '$(Platform)' == 'AnyCPU' Or 
                             '$(Platform)' == 'Any CPU'">x86</Architecture>
    <Architecture Condition="'$(Platform)'=='amd64'">x64</Architecture>
    <Architecture Condition="'$(Architecture)'==''">x64</Architecture>

    <!-- No suitable value was found - select a default --> 
    <Architecture Condition="'$(Architecture)' !='x86' And 
                             '$(Architecture)' !='x64' And 
                             '$(Architecture)' !='arm' And 
                             '$(Architecture)' !='arm64'">x64</Architecture>

note: In theory, we can't deal with arm or arm64 either yet; I don't expect we'll ever learn to deal with arm(32)..