[build] fix broken incrementality of Mono.Android.csproj#10578
Merged
[build] fix broken incrementality of Mono.Android.csproj#10578
Mono.Android.csproj#10578Conversation
I noticed this was happening like for *every* build...
> .\dotnet-local.cmd build .\src\Mono.Android\Mono.Android.csproj -bl
...
Build succeeded with 78 warning(s) in 125.6s
Even with no changes!
I tracked this down to this chain of events:
Mono.Android.csproj
Target CoreCompile
Building target "CoreCompile" completely.
Input file "Android.Runtime\JNIEnv.g.cs" is newer than output file "obj\Debug\net10.0\android-36\Mono.Android.pdb".
...
Target _BuildJNIEnv
Building target "_BuildJNIEnv" completely.
Input file "..\..\bin\BuildDebug\jnienv-gen.dll" is newer than output file "../../src/Mono.Android/Android.Runtime/JNIEnv.g.cs".
...
Target CoreCompile
Building target "CoreCompile" completely.
Input file "D:\src\xamarin-android\bin\Debug\lib\packs\Microsoft.Android.Sdk.Windows\36.1.99\Sdk\AutoImport.props" is newer than output file "obj\Debug\net9.0\jnienv-gen.pdb".
Reviewing the `_GenerateBundledVersions` MSBuild target, it just runs
every time! No `Inputs` or `Outputs` are defined, so it is always
considered out-of-date.
I created a new `_WriteBundledVersionsCache` target that writes a
cache file with all important properties, and then made
`_GenerateBundledVersions` depend on that target, and added `Inputs`
and `Outputs` to it.
This appears to speed up our builds significantly!
> .\dotnet-local.cmd build .\src\Mono.Android\Mono.Android.csproj -bl
...
Build succeeded in 2.1s
grendello
approved these changes
Nov 7, 2025
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I noticed this was happening like for every build...
Even with no changes!
I tracked this down to this chain of events:
Reviewing the
_GenerateBundledVersionsMSBuild target, it just runs every time! NoInputsorOutputsare defined, so it is always considered out-of-date.I created a new
_WriteBundledVersionsCachetarget that writes a cache file with all important properties, and then made_GenerateBundledVersionsdepend on that target, and addedInputsandOutputsto it.This appears to speed up our builds significantly!