fix: dart compiler ran out of memory trying to compile linker?

[eseidel]

This actually looks like difficulty compiling the aot-tools.dill, not the linker itself running out of memory:

✗ Failed to link AOT files: Exception: Failed to link: Exhausted heap space, trying to allocate 35232 bytes.
Crash when compiling $HOME/shorebird/bin/cache/artifacts/aot-tools/9472e50354253fde3f2cdb25d8115f7aa6d3c68a/aot-tools:
Out of Memory

#0      _StringBase._concatRangeNative (dart:core-patch/string_patch.dart:962:78)
#1      _JsonStringStringifier.stringify (dart:convert/json.dart:968:19)
#2      SourceLibraryBuilder.addProblem (package:front_end/src/fasta/source/source_library_builder.dart:1868:52)
#3      SourceLoader.tokenize (package:front_end/src/fasta/source/source_loader.dart:949:24)
#4      _rootRunUnary (dart:async/zone.dart:1407:47)
#5      _CustomZone.runUnary (dart:async/zone.dart:1308:19)
#6      _FutureListener.handleValue (dart:async/future_impl.dart:162:18)
#7      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:846:45)
#8      Future._propagateToListeners (dart:async/future_impl.dart:875:13)
#9      Future._completeWithValue (dart:async/future_impl.dart:647:5)
#10     Future._asyncCompleteWithValue.<anonymous closure> (dart:async/future_impl.dart:721:7)
#11     _rootRun (dart:async/zone.dart:1399:13)
#12     _CustomZone.run (dart:async/zone.dart:1301:19)
#13     _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:1233:23)
#14     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#15     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
#16     _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:118:13)
#17     _Timer._runTimers (dart:isolate-patch/timer_impl.dart:405:11)
#18     _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:429:5)
#19     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

 (2250.4s)

[eseidel]

I'm confused as to why source_library_builder would be called at all. This should be compiling a .dill file, which is kernel, not source.

[eseidel]

I think what's going on is the customer is trying to release to an older version of Flutter with our newer shorebird client, which is trying to execute a macho file as a .dart file. :)