`fuchsia_tester --coverage` hangs on dartfmt_extras_tests

[garymm]

Steps to reproduce:

1. Check out fuchsia with layer set to topaz.
2. patch replace third_party/dart-pkg/git/flutter/packages/flutter_tools/bin/fuchsia_tester.dart with the copy from upstream flutter: curl https://raw.githubusercontent.com/flutter/flutter/master/packages/flutter_tools/bin/fuchsia_tester.dart -o third_party/dart-pkg/git/flutter/packages/flutter_tools/bin/fuchsia_tester.dart. This won't be needed once the version of flutter in fuchsia gets updated.
3. fx clean-build x64
4. out/x64/host_x64/dart-tools/fuchsia_tester --packages=$PWD/out/x64/dartlang/gen/topaz/tools/dartfmt_extras/dartfmt_extras_tests_library.packages --shell=$PWD/out/x64/host_x64/flutter_tester --test-directory=$PWD/topaz/tools/dartfmt_extras/test --coverage

Expected result:
Test runs to completion and generates coverage data.

Observed result:
Test hangs for 2 minutes, then an exception is raised and the process stays stuck.

00:00 +0: loading /usr/local/google/home/garymm/fuchsia/topaz/tools/dartfmt_extras/test/directives_test.dart                        S
hell: Do not know weight for: TeXGyreSchola (BoldItalic)
Shell: Do not know weight for: TeXGyreSchola (BoldItalic)
02:01 +2: ... Double quotes should be fixed correctly.                                                                              u
nhandled error during test:
/usr/local/google/home/garymm/fuchsia/topaz/tools/dartfmt_extras/test/directives_test.dart
Exception: Timed out while collecting coverage.
#0      CoverageCollector.collectCoverage.<anonymous closure> (package:flutter_tools/src/test/coverage_collector.dart:64)
#1      StackZoneSpecification._run (package:stack_trace/src/stack_zone_specification.dart:209)
#2      StackZoneSpecification._registerCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart:119)
#3      _rootRun (dart:async/zone.dart:1122)
#4      _CustomZone.run (dart:async/zone.dart:1023)
#5      Future.timeout.<anonymous closure> (dart:async/future_impl.dart:731)
#6      StackZoneSpecification._run (package:stack_trace/src/stack_zone_specification.dart:209)
#7      StackZoneSpecification._registerCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart:119)
#8      _rootRun (dart:async/zone.dart:1122)
#9      _CustomZone.run (dart:async/zone.dart:1023)
#10     _CustomZone.runGuarded (dart:async/zone.dart:925)
#11     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965)
#12     StackZoneSpecification._run (package:stack_trace/src/stack_zone_specification.dart:209)
#13     StackZoneSpecification._registerCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart:119)
#14     _rootRun (dart:async/zone.dart:1126)
#15     _CustomZone.run (dart:async/zone.dart:1023)
#16     _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:949)
#17     Timer._createTimer.<anonymous closure> (dart:async-patch/dart:async/timer_patch.dart:21)
#18     _Timer._runTimers (dart:isolate-patch/dart:isolate/timer_impl.dart:382)
#19     _Timer._handleMessage (dart:isolate-patch/dart:isolate/timer_impl.dart:416)
#20     _RawReceivePortImpl._handleMessage (dart:isolate-patch/dart:isolate/isolate_patch.dart:165)

So there are really 2 issues here:

1. This particular test triggers a timeout during coverage collection. Not sure if the problem is in the flutter coverage collector or in the code under test.
2. Once the timeout is triggered, the fuchsia_tester process hangs rather than exits cleanly.

CC @yyoon @cbracken @tvolkert

[cbracken]

@tvolkert I'm about to be out for a couple weeks but it'd be interesting to instrument collect() in package:coverage and see where it's hanging. Collection should take on the order of seconds once it gets started, so I'd imagine we're failing to meet some precondition to get started.

Looks like we're calling collect() with waitPaused: false so the most obvious culprit seems like it'd be just connecting to the VM service.

[jason-simmons]

It looks like one of the flutter_tester processes started by this test suite is segfaulting during the isolate.getSourceReport RPC. collectCoverage in flutter_tools is then timing out waiting for a response from the dead process.

Follow ups:

• collectCoverage should exit if the child process dies
• why is getSourceReport crashing on this test?

[cbracken]

/cc @a-siva for the segfault on getSourceReport

[a-siva]

@jason-simmons did we get any stack trace on the process that segfaulted?

[jason-simmons]

Here is a stack trace that I captured from this crash:

#0  id (this=<optimized out>) at ../../third_party/dart/runtime/vm/object.h:956
#1  IsDynamicClass (this=<optimized out>) at ../../third_party/dart/runtime/vm/object.h:1111
#2  dart::Class::TypeTestNonRecursive (cls=..., test_kind=dart::Object::kIsMoreSpecificThan, type_arguments=..., other=..., 
    other_type_arguments=..., bound_error=0x0, bound_trail=0x0, space=dart::Heap::kOld) at ../../third_party/dart/runtime/vm/object.cc:4099
#3  0x0000000001272744 in TypeTest (this=<optimized out>, test_kind=<optimized out>, type_arguments=..., other=..., other_type_arguments=..., 
    bound_error=<optimized out>, bound_trail=<optimized out>, space=<optimized out>) at ../../third_party/dart/runtime/vm/object.cc:4250
#4  dart::AbstractType::TypeTest (this=<optimized out>, test_kind=dart::Object::kIsMoreSpecificThan, other=..., bound_error=0x0, 
    bound_trail=0x0, space=<optimized out>) at ../../third_party/dart/runtime/vm/object.cc:17340
#5  0x000000000147a461 in IsMoreSpecificThan (this=<optimized out>, other=..., bound_error=0x7ffd037fcb98, space=dart::Heap::kOld, 
    bound_trail=<optimized out>) at ../../third_party/dart/runtime/vm/object.h:6259
#6  dart::CompileType::CanComputeIsInstanceOf (this=0x6c487f8, type=..., is_nullable=true, is_instance=0x7ffd037fb837)
    at ../../third_party/dart/runtime/vm/compiler/backend/type_propagator.cc:767
#7  0x0000000001498906 in IsAssignableTo (this=0x0, type=...) at ../../third_party/dart/runtime/vm/compiler/backend/il.h:101
#8  dart::EffectGraphVisitor::CanSkipTypeCheck (this=0x7ffd037fb9c0, token_pos=..., value=0x6c487c8, dst_type=..., dst_name=...)
    at ../../third_party/dart/runtime/vm/compiler/frontend/flow_graph_builder.cc:1248
#9  0x0000000001497adb in dart::EffectGraphVisitor::BuildAssignableValue (this=0x7ffd037fb9c0, token_pos=..., value=0x6c487c8, dst_type=..., 
    dst_name=...) at ../../third_party/dart/runtime/vm/compiler/frontend/flow_graph_builder.cc:1445
#10 0x00000000014a96ac in dart::EffectGraphVisitor::VisitStoreInstanceFieldNode (this=0x7ffd037fb9c0, node=0x6c47878)
    at ../../third_party/dart/runtime/vm/compiler/frontend/flow_graph_builder.cc:3487
#11 0x00000000014ad3f0 in dart::EffectGraphVisitor::VisitSequenceNode (this=<optimized out>, node=<optimized out>)
    at ../../third_party/dart/runtime/vm/compiler/frontend/flow_graph_builder.cc:4004
#12 0x00000000014ad3f0 in dart::EffectGraphVisitor::VisitSequenceNode (this=<optimized out>, node=<optimized out>)
    at ../../third_party/dart/runtime/vm/compiler/frontend/flow_graph_builder.cc:4004
#13 0x00000000014af983 in dart::FlowGraphBuilder::BuildGraph (this=0x7ffd037fbd40)
    at ../../third_party/dart/runtime/vm/compiler/frontend/flow_graph_builder.cc:4462
#14 0x000000000150644b in dart::DartCompilationPipeline::BuildFlowGraph (this=<optimized out>, zone=<optimized out>, 
    parsed_function=<optimized out>, ic_data_array=..., osr_id=<optimized out>, optimized=<optimized out>)
    at ../../third_party/dart/runtime/vm/compiler/jit/compiler.cc:174
#15 0x00000000015092ec in dart::CompileParsedFunctionHelper::Compile (this=0x7ffd037fc598, pipeline=0x6c40068)
    at ../../third_party/dart/runtime/vm/compiler/jit/compiler.cc:826
#16 0x000000000150a462 in dart::CompileFunctionHelper (pipeline=<optimized out>, function=..., optimized=<optimized out>, 
    osr_id=<optimized out>) at ../../third_party/dart/runtime/vm/compiler/jit/compiler.cc:1017
#17 0x000000000150b0a4 in dart::Compiler::EnsureUnoptimizedCode (thread=0x39933d0, function=...)
    at ../../third_party/dart/runtime/vm/compiler/jit/compiler.cc:1265
#18 0x00000000013b6bba in dart::SourceReport::VisitFunction (this=0x7ffd037fd148, jsarr=0x7ffd037fd0c0, func=...)
    at ../../third_party/dart/runtime/vm/source_report.cc:389
#19 0x00000000013b70d7 in dart::SourceReport::VisitLibrary (this=0x7ffd037fd148, jsarr=0x7ffd037fd0c0, lib=...)
    at ../../third_party/dart/runtime/vm/source_report.cc:482
#20 0x00000000013b7710 in dart::SourceReport::PrintJSON (this=0x7ffd037fd148, js=0x7ffd037fd2d0, script=..., start_pos=..., end_pos=...)
    at ../../third_party/dart/runtime/vm/source_report.cc:519
#21 0x00000000013a3426 in dart::GetSourceReport (thread=<optimized out>, js=0x7ffd037fd2d0)
    at ../../third_party/dart/runtime/vm/service.cc:3004
#22 0x000000000139bcf6 in dart::Service::InvokeMethod (I=<optimized out>, msg=..., parameters_are_dart_objects=<optimized out>)
    at ../../third_party/dart/runtime/vm/service.cc:869
#23 0x000000000139c3f2 in dart::Service::HandleIsolateMessage (isolate=0x39b41b0, msg=...) at ../../third_party/dart/runtime/vm/service.cc:917
#24 0x0000000001225eb8 in dart::IsolateMessageHandler::HandleMessage (this=0x39b3e50, message=0x7ff56c0a3b90)
    at ../../third_party/dart/runtime/vm/isolate.cc:565
#25 0x000000000124f91d in dart::MessageHandler::HandleMessages (this=0x39b3e50, ml=0x7ffd037fe6e8, allow_normal_messages=true, 
    allow_multiple_normal_messages=<optimized out>) at ../../third_party/dart/runtime/vm/message_handler.cc:231
#26 0x000000000124fa2e in dart::MessageHandler::HandleNextMessage (this=0x39b3e50) at ../../third_party/dart/runtime/vm/message_handler.cc:290
#27 0x0000000001533d14 in Dart_HandleMessage () at ../../third_party/dart/runtime/vm/dart_api_impl.cc:1664
#28 0x0000000000d975fc in tonic::DartMessageHandler::OnHandleMessage (this=0x3972f00, dart_state=0x39b3440)
    at ../../topaz/lib/tonic/dart_message_handler.cc:115
#29 0x0000000000d54478 in fml::MessageLoopImpl::RunExpiredTasks (this=<optimized out>)
    at ../../third_party/flutter/fml/message_loop_impl.cc:141
#30 0x0000000000d5806a in fml::MessageLoopLinux::Run (this=0x39260c0) at ../../third_party/flutter/fml/platform/linux/message_loop_linux.cc:69
#31 0x0000000000d546ff in fml::MessageLoopImpl::DoRun (this=0x39260c0) at ../../third_party/flutter/fml/message_loop_impl.cc:77
#32 0x0000000000d4c7ae in shell::RunTester (settings=..., run_forever=false) at ../../third_party/flutter/shell/testing/tester_main.cc:207
#33 0x0000000000d4ce67 in main (argc=<optimized out>, argv=<optimized out>) at ../../third_party/flutter/shell/testing/tester_main.cc:271

[a-siva]

thanks @jason-simmons

[crelier]

@garymm, I suppose this patch is not needed anymore?
https://github.com/flutter/flutter/raw/packages/flutter_tools/bin/fuchsia_tester.dart

I do not find it at that url

[jason-simmons]

Grab that file from the Flutter tip of tree:
https://github.com/flutter/flutter/blob/master/packages/flutter_tools/bin/fuchsia_tester.dart