OutOfMemoryException

[megerlms]

I'm using altcover to cover my unit tests written with xUnit.
Sometimes it happens that I get an OutOfMemoryException when the coverage tool is generating the result file.
The PC hat 8GB RAM that should be sufficient.
The exception looks like this:
.....coverage.xml.0.acv (8.628.739b)

Unhandled Exception:
System.OutOfMemoryException: Insufficient memory to continue the execution of the program.
at (wrapper alloc) System.Object.AllocVector(intptr,intptr)
at System.Collections.Generic.List1[T].set_Capacity (System.Int32 value) <0x7fdffebcd190 + 0x00053> in <0f8aeac9d63d4b8aa575761bb4e65b79>:0 at System.Collections.Generic.List1[T].AddWithResize (T item) <0x7fdffebcd560 + 0x00063> in <0f8aeac9d63d4b8aa575761bb4e65b79>:0
at System.Collections.Generic.List1[T].Add (T item) <0x7fdffebcd510 + 0x00048> in <0f8aeac9d63d4b8aa575761bb4e65b79>:0 at AltCover.Runner.sink@432 (System.Collections.Generic.ICollection1[T] hits, System.IO.BinaryReader formatter, Microsoft.FSharp.Core.Unit unitVar0) [0x000d5] in :0
at AltCover.Runner+CollectResults@425.Invoke (System.String f) [0x00076] in :0
at Microsoft.FSharp.Collections.SeqModule.Iterate[T] (Microsoft.FSharp.Core.FSharpFunc2[T,TResult] action, System.Collections.Generic.IEnumerable1[T] source) [0x0002c] in <5b5a6cc1904cf4daa7450383c16c5a5b>:0
at AltCover.Runner.CollectResults (System.Collections.Generic.ICollection1[T] hits, System.String report) [0x00044] in <ff776df29b8d4500bb9107f1fcd3295d>:0 at AltCover.Runner.MonitorBase (System.Collections.Generic.ICollection1[T] hits, System.String report, Microsoft.FSharp.Core.FSharpFunc2[T,TResult] payload, Microsoft.FSharp.Collections.FSharpList1[T] args) [0x0001b] in :0
at AltCover.Runner+GetMonitor@748.Invoke (System.Collections.Generic.ICollection1[T] hits, System.String report, Microsoft.FSharp.Core.FSharpFunc2[T,TResult] payload, Microsoft.FSharp.Collections.FSharpList1[T] args) [0x00000] in <ff776df29b8d4500bb9107f1fcd3295d>:0 at AltCover.Runner+value@776.Invoke (Microsoft.FSharp.Core.Unit unitVar0) [0x00058] in <ff776df29b8d4500bb9107f1fcd3295d>:0 at AltCover.CommandLine.doPathOperation[a] (Microsoft.FSharp.Core.FSharpFunc2[T,TResult] f, a defaultValue, System.Boolean store) [0x000a1] in :0
at AltCover.Runner.DoCoverage[a] (System.String[] arguments, a options1) [0x00051] in :0
at AltCover.Main.Main (System.String[] arguments) [0x00035] in :0
at AltCover.Main+EffectiveMain@469.Invoke (System.String[] arguments) [0x00000] in :0
[ERROR] FATAL UNHANDLED EXCEPTION: System.OutOfMemoryException: Insufficient memory to continue the execution of the program.
at (wrapper alloc) System.Object.AllocVector(intptr,intptr)
at System.Collections.Generic.List1[T].set_Capacity (System.Int32 value) <0x7fdffebcd190 + 0x00053> in <0f8aeac9d63d4b8aa575761bb4e65b79>:0 at System.Collections.Generic.List1[T].AddWithResize (T item) <0x7fdffebcd560 + 0x00063> in <0f8aeac9d63d4b8aa575761bb4e65b79>:0
at System.Collections.Generic.List1[T].Add (T item) <0x7fdffebcd510 + 0x00048> in <0f8aeac9d63d4b8aa575761bb4e65b79>:0 at AltCover.Runner.sink@432 (System.Collections.Generic.ICollection1[T] hits, System.IO.BinaryReader formatter, Microsoft.FSharp.Core.Unit unitVar0) [0x000d5] in :0
at AltCover.Runner+CollectResults@425.Invoke (System.String f) [0x00076] in :0
at Microsoft.FSharp.Collections.SeqModule.Iterate[T] (Microsoft.FSharp.Core.FSharpFunc2[T,TResult] action, System.Collections.Generic.IEnumerable1[T] source) [0x0002c] in <5b5a6cc1904cf4daa7450383c16c5a5b>:0
at AltCover.Runner.CollectResults (System.Collections.Generic.ICollection1[T] hits, System.String report) [0x00044] in <ff776df29b8d4500bb9107f1fcd3295d>:0 at AltCover.Runner.MonitorBase (System.Collections.Generic.ICollection1[T] hits, System.String report, Microsoft.FSharp.Core.FSharpFunc2[T,TResult] payload, Microsoft.FSharp.Collections.FSharpList1[T] args) [0x0001b] in :0
at AltCover.Runner+GetMonitor@748.Invoke (System.Collections.Generic.ICollection1[T] hits, System.String report, Microsoft.FSharp.Core.FSharpFunc2[T,TResult] payload, Microsoft.FSharp.Collections.FSharpList1[T] args) [0x00000] in <ff776df29b8d4500bb9107f1fcd3295d>:0 at AltCover.Runner+value@776.Invoke (Microsoft.FSharp.Core.Unit unitVar0) [0x00058] in <ff776df29b8d4500bb9107f1fcd3295d>:0 at AltCover.CommandLine.doPathOperation[a] (Microsoft.FSharp.Core.FSharpFunc2[T,TResult] f, a defaultValue, System.Boolean store) [0x000a1] in :0
at AltCover.Runner.DoCoverage[a] (System.String[] arguments, a options1) [0x00051] in :0
at AltCover.Main.Main (System.String[] arguments) [0x00035] in :0
at AltCover.Main+EffectiveMain@469.Invoke (System.String[] arguments) [0x00000] in :0

Mono version used is:
mono --version
Mono JIT compiler version 5.16.0.220 (tarball Mon Nov 26 17:17:59 UTC 2018)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: __thread
SIGSEGV: altstack
Notifications: epoll
Architecture: amd64
Disabled: none
Misc: softdebug
Interpreter: yes
LLVM: yes(3.6.0svn-mono-/)
GC: sgen (concurrent by default)

OS is: Ubuntu 18.04

[SteveGilham]

The compression used in the visit file format means there can be a lot of visits per output byte if there are repetitive patterns.

As a work-around, if you are interested only in "did I visit this place?", rather than "how many times did I do so?", the --single command line option can significantly reduce the amount of data being processed.

[megerlms]

Indeed, I tried this option already. Unfortunately I could not mention any difference.
The calls I do use are....

...for instrumentation:
$ALTCOV --single -i $WORKING_DIR -o $WORKING_DIR/instr/ -s xunit* -s ${TEST_ASM:0:-4} -s AWS*

...for running:
$ALTCOV Runner -x mono -c coverage/${TEST_ASM}.cort.xml -r=${WORKING_DIR}/instr/ -- $XUNIT ${WORKING_DIR}/instr/${TEST_ASM} -xml ./testresults/${TEST_ASM}.tests.xml

Note:
$ALTCOVER points to the altcover executable
$XUNIT points to the xUnit executable

[SteveGilham]

I'll have to do some more investigation to see if I can find why --single seems to have no effect for you. In the mean time, pre-release build 656 contains a change that should mitigate the memory use for the intermediate processing, where the stack trace is indicating.

Could you give that a try?

[megerlms]

I was some days occupied by other stuff, I will give it a try.

[megerlms]

I tried the new release 659 and the exception didn't appear. Also the --single option seems to work.
Thanks for the quick fix!