[Xamarin.Android.Build.Tasks] Run aapt2 compile incrementally.

[dellis1972]

The aapt2 compile command runs in two modes. The one we
currently use is the archive mode. We calling aapt2 compile
with the --dir argument you end up generating one flata
archive for all the files. The side effect of this is that even
if you only change one file, it will need to regenerate the
entire flata archive.

But it has a second mode. Rather than using --dir you just send
in a single file. This then writes a single .flat file to the
output directory. While this does mean you have to call aapt2 compile
for EVERY file, it does mean we can leverage MSbuilds support for
partial targets. This means MSbuild will detect ONLY the files which
changed and allow us to call aapt2 compile with just THOSE files.

While this may impact on initial build times, the goal is to make
incremental builds quicker. This is especially true for users to
use ALLOT of AndroidResource items.

A note regarding the aapt2 daemon mode. In order to write
accented characters we need to set the StandardInput
encoding to UTF8. This is not possible directly
in netstandard 2.0. So we have to use Console.InputEncoding
instead. Also not that we MUST not include a BOM when writting
the commands. This is because aapt2 will try to parse the BOM
as command characters.

Also the aapt2 link command sometimes reports it is "Done" before
it has even written the archive for the file. So we can get into a
position where we think we are done but the file is not on disk.
So we have had to include a nasty wait which will poll for the
existence of the expected output file and only return when it
exists. The good news is we know at this point if the command
failed or not, so we can bypass the check on failure.

Test	Latest Stable	Aapt2 Daemon
From Clean	00:00:27.92	00:00:27.41
No Changes	00:00:03.14	00:00:03.72
Alter Layout	00:00:16.37	00:00:05.53

[dellis1972]

@jonathanpeppers should we make this feature optional? So users can turn it on/off. Also should we restrict this only to app projects?

[jonathanpeppers]

@dellis1972 I think this could be just the new behavior if all existing projects we know about continue to work. If you reopen this PR on a branch on the xamarin org, the QA tests will be able to run (they can't run on a fork 😞 ).

I think it would also be good to write a test checking if the target builds partially: https://github.com/xamarin/xamarin-android/blob/e2e1a846ca6136f0a3bac5ffb48277938ed5c204/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.ProjectTools/Common/BuildOutput.cs#L65-L76

[dellis1972]

I think it would also be good to write a test checking if the target builds partially:

Yup, this is till a work in progress so I'll get to that too :)

[dellis1972]

/azp run

[azure-pipelines]

Pull request contains merge conflicts.

[dellis1972]

Windows tests are failing with

 C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:23  7556  7648 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]
  C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:23  1388  9012 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]
  C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:24  7328 10176 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]
  C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:24  1272   504 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]
  C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:25   912  5228 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]
  C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:25  9752  5668 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]
  C:\A\xamarin-v00000G-1\_work\1\s\bin\Release\lib\xamarin.android\xbuild\Xamarin\Android\Xamarin.Android.Aapt2.targets(151,3): warning APT2000: aapt2.exe F 02-06 17:05:26  6912  8696 Command.cpp:41] Check failed: android::base::UTF8PathToWindowsLongPath(arg.data(), &path16) Failed to convert file path to UTF-16: file path C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\obj\Release\flat\ [C:\A\xamarin-v00000G-1\_work\1\s\bin\TestRelease\temp\BuildReleaseAppWithA InItAndÜmläüts(Truedxr8)\UnnamedProject.csproj]

so it looks like the daemon mode does not work with long paths on windows 🤦‍♂

[jonathanpeppers]

Should the first use of this daemon be behind a feature flag? Or is it definitely going to be better to use by default?

[dellis1972]

/azp run

[azure-pipelines]

Pull request contains merge conflicts.

[dellis1972]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[dellis1972]

@jonathanpeppers ok we are down to 1 failure

EXEC : error : aprofutil: Unable to read profile through local port: 9013.

its the profile AOT one.

[brendanzagaeski]

Draft release notes

Here is the note I'm thinking of including for this pull request:

### Build and deployment performance

  * [GitHub PR 4190](https://github.com/xamarin/xamarin-android/pull/4190):
    Switch to running AAPT2 in single-file mode rather than `--dir` mode.  This
    reduced the total incremental build time from about 16.4 seconds to about 5.5
    seconds for a test project when a single Android resource file was changed
    between builds.

To suggest something different, feel free to reply in this PR or add a Documentation/release-notes/4190.md file with the new suggestion. Thanks in advance!

[acuntex]

Is it possible to disable this new feature?

We suspect this feature to break the functionality of ResizetizerNT and since it's apparently impossible to downgrade Xamarin.Android after a Visual Studio for Mac upgrade we are not able to build the Android app.

Edit: Apparently it's possible to downgrade Xamarin.Android by installing the old pkg. Apparently it is related to this, ResizetizerNT works fine with 10.3

[dellis1972]

@acuntex its is not possible to disable this feature, and I can't see how it would effect ResizetizerNT. I would recommend you open an Issue in this repo https://github.com/xamarin/xamarin-android/issues/new/choose . Provide as much detail as possible including diagnostic build logs which show the error you are getting.