ConcurrentModifictionException error
campbebj opened this issue ยท 5 comments
Hey im getting the following error and then my client is just freezing up after that. I think it might be a reaction to be displaying litematica schematics but im not 100% sure. is there anything i can provide to help with debugging?
[16:38:09] [CullThread/INFO]: [STDERR]: java.util.ConcurrentModificationException
[16:38:09] [CullThread/INFO]: [STDERR]: at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445)
[16:38:09] [CullThread/INFO]: [STDERR]: at java.util.HashMap$EntryIterator.next(HashMap.java:1479)
[16:38:09] [CullThread/INFO]: [STDERR]: at java.util.HashMap$EntryIterator.next(HashMap.java:1477)
[16:38:09] [CullThread/INFO]: [STDERR]: at dev.tr7zw.entityculling.CullTask.run(CullTask.java:56)
[16:38:09] [CullThread/INFO]: [STDERR]: at java.lang.Thread.run(Thread.java:748)
Hmm I have no clue how litematica schematics are rendered, but yea it might be an issue with that. But that at worst should kill the cull thread, not freeze up the client. I'll look into it.
I don't think it's an issue with Litematica as I'm getting the error as well.
[03:06:37] [CullThread/INFO]: [STDERR]: java.util.ConcurrentModificationException
[03:06:37] [CullThread/INFO]: [STDERR]: at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1584)
[03:06:37] [CullThread/INFO]: [STDERR]: at java.base/java.util.HashMap$EntryIterator.next(HashMap.java:1617)
[03:06:37] [CullThread/INFO]: [STDERR]: at java.base/java.util.HashMap$EntryIterator.next(HashMap.java:1615)
[03:06:37] [CullThread/INFO]: [STDERR]: at dev.tr7zw.entityculling.CullTask.run(CullTask.java:56)
[03:06:37] [CullThread/INFO]: [STDERR]: at java.base/java.lang.Thread.run(Thread.java:831)
Perhaps you could use a ConcurrentHashMap
if you're using multiple threads? Typical operations still don't require synchronization, so I don't think performance would be a big issue, and a ConcurrentHashMap
can be iterated over and modified by different threads.
My mod list:
Fabric Mods:
advancements-enlarger: Advancements Enlarger 0.2.3
amecs: Amecs 1.3.3+mc.1.16.3
amecsapi: Amecs API 1.1.3+mc1.16.5
angerable-patch: Angerable Patch 1.1.0-1.16.4
appleskin: AppleSkin 1.0.11
architectury: Architectury 1.8.131
artifice: Artifice 0.14.6+1.16.5
autoconfig1u: Auto Config v1 Updated 3.3.1
beaconsforall: Beacons For All 1.4.1-1.16.5
betterdroppeditems: Better Dropped Items 1.2.4-1.16.2
bettergraves: Better Graves 0.4.1
bettersleeping: Better Sleeping 0.4.0
betterthanmending: BetterThanMending 1.3.0
blue_endless_jankson: jankson 1.2.0
cameraoverhaul: Camera Overhaul 1.2.2-fabric-universal
can-i-mine-this-block: cAn i MiNe thIS bLOCk? 1.0.2
carpet: Carpet Mod in Fabric 1.4.28
carpet-extra: Carpet Extra 1.4.27
cloth-basic-math: Cloth Basic Math 0.5.1
cloth-client-events-v0: Cloth Client Events v0 1.5.47
cloth-config2: Cloth Config v4 4.11.14
colormatic: Colormatic 2.2.8+mc.1.16.3
com_github_shevek_parallelgzip: parallelgzip master-SNAPSHOT
com_moandjiezana_toml_toml4j: toml4j 0.7.2
com_squareup_moshi_moshi: moshi 1.9.2
com_squareup_okio_okio: okio 1.16.0
cotton-config: Cotton Config 1.0.0-rc.7
cotton-logging: Cotton Logging 1.0.0-rc.4
craftpresence: CraftPresence 1.7.6
dynamicfps: Dynamic FPS 2.0.1
dynamicsoundfilters: Dynamic Sound Filters 1.2.0+1.16.5
elytra_swap: Elytra Swap 2.2.0-1.16.2
enhancedblockentities: Enhanced Block Entities 0.1
entityculling: EntityCulling-Fabric 1.0.2
fabric: Fabric API 0.32.0+1.16
fabric-api-base: Fabric API Base 0.2.1+9354966b7d
fabric-api-lookup-api-v1: Fabric API Lookup API (v1) 1.0.0+dc716ea17d
fabric-biome-api-v1: Fabric Biome API (v1) 3.1.1+ca58154a7d
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.5+ca58154a7d
fabric-command-api-v1: Fabric Command API (v1) 1.1.0+f9b3753b7d
fabric-commands-v0: Fabric Commands (v0) 0.2.2+ca58154a7d
fabric-containers-v0: Fabric Containers (v0) 0.1.11+9354966b7d
fabric-content-registries-v0: Fabric Content Registries (v0) 0.2.1+ca58154a7d
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.1.3+ca58154a7d
fabric-diagonal-panes: Fabric Diagonal Panes 0.4.0
fabric-dimensions-v1: fabric-dimensions-v1 2.0.6+9354966b7d
fabric-entity-events-v1: Fabric Entity Events (v1) 1.0.3+ca58154a7d
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.4.2+ca58154a7d
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.1+ca58154a7d
fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.6+ca58154a7d
fabric-item-api-v1: Fabric Item API (v1) 1.2.1+ca58154a7d
fabric-item-groups-v0: Fabric Item Groups (v0) 0.2.3+ca58154a7d
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.4+9354966b7d
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.1+ca58154a7d
fabric-language-kotlin: Fabric Language Kotlin 1.4.21+build.1
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 1.2.1+ca58154a7d
fabric-loot-tables-v1: Fabric Loot Tables (v1) 1.0.2+ca58154a7d
fabric-mining-levels-v0: Fabric Mining Levels (v0) 0.1.3+ca58154a7d
fabric-models-v0: Fabric Models (v0) 0.2.1+ca58154a7d
fabric-mumblelink-mod: MumbleLink 0.7.5
fabric-networking-api-v1: Fabric Networking API (v1) 1.0.1+ca58154a7d
fabric-networking-blockentity-v0: Fabric Networking Block Entity (v0) 0.2.8+ca58154a7d
fabric-networking-v0: Fabric Networking (v0) 0.3.2+ca58154a7d
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 1.9.4+9354966b7d
fabric-object-builders-v0: Fabric Object Builders (v0) 0.7.2+ca58154a7d
fabric-particles-v1: Fabric Particles (v1) 0.2.4+ca58154a7d
fabric-registry-sync-v0: Fabric Registry Sync (v0) 0.7.4+ca58154a7d
fabric-renderer-api-v1: Fabric Renderer API (v1) 0.4.1+ca58154a7d
fabric-renderer-indigo: Fabric Renderer - Indigo 0.4.4+ca58154a7d
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 2.2.1+ca58154a7d
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.1.5+ca58154a7d
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 0.1.13+ca58154a7d
fabric-rendering-v0: Fabric Rendering (v0) 1.1.2+ca58154a7d
fabric-rendering-v1: Fabric Rendering (v1) 1.5.1+ca58154a7d
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.4.2+ca58154a7d
fabric-screen-api-v1: Fabric Screen API (v1) 1.0.0+c045166c7d
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.1.5+9354966b7d
fabric-start-the-music: Start the Music! 0.2.1
fabric-structure-api-v1: Fabric Structure API (v1) 1.1.4+ca58154a7d
fabric-tag-extensions-v0: Fabric Tag Extensions (v0) 1.1.1+ca58154a7d
fabric-textures-v0: Fabric Textures (v0) 1.0.6+ca58154a7d
fabric-tool-attribute-api-v1: Fabric Tool Attribute API (v1) 1.2.6+ca58154a7d
fabric-tree-chopper: Fabric Tree Chopper 0.6.1
fabricloader: Fabric Loader 0.11.2
fairenchanting: FairEnchanting 1.2.0
fiber: fiber 0.23.0-2
fiber2cloth: Fiber To Cloth 3.1.0
harvest: Harvest 1.2.12
hydrogen: Hydrogen 0.2-SNAPSHOT
indium: Indium 1.0.0
inventorysorter: Inventory Sorter 1.7.7-1.16
iris: Iris 0.2.0-sodium_compatibility
itemmodelfix: Item Model Fix 1.0.0
jankson: Jankson 3.0.1+j1.2.0
java: OpenJDK 64-Bit Server VM 16
kirin: Kirin UI 1.7-1.16.2
krypton: Krypton 0.1.2
kyrptconfig: Kytpt Config 1.1.6-1.16
lambdabettergrass: LambdaBetterGrass 1.0.3+1.16
lambdynlights: LambDynamicLights 1.3.4+1.16
lazydfu: LazyDFU 0.1.2
lightoverlay: Light Overlay 5.8.0
lithium: Lithium 0.6.4-SNAPSHOT
malilib: MaLiLib 0.10.0-dev.21+arne.2
minecraft: Minecraft 1.16.5
mm: Manningham Mills 2.1
modmenu: Mod Menu 1.16.8
modupdater: ModUpdater 1.1.11+1.16.2-rc2
mostructures: Mo' Structures 1.1.0+mc.1.16.5
mousewheelie: Mouse Wheelie 1.6.4+mc1.16.4
net_gegy1000_just-now: just-now 0.1.0-SNAPSHOT
notenoughanimations: NotEnoughAnimations 1.0.3
notenoughcrashes: Not Enough Crashes 3.1.8
okzoomer: Ok Zoomer 4.0.1+1.16.2
org_apache_commons_commons-compress: commons-compress 1.19
org_aperlambda_lambdajcommon: lambdajcommon 1.8.1
org_codehaus_groovy_groovy: groovy 3.0.3
org_codehaus_groovy_groovy-jsr223: groovy-jsr223 3.0.3
org_jetbrains_annotations: annotations 20.0.0
org_jetbrains_kotlin_kotlin-reflect: kotlin-reflect 1.4.21
org_jetbrains_kotlin_kotlin-stdlib: kotlin-stdlib 1.4.21
org_jetbrains_kotlin_kotlin-stdlib-jdk7: kotlin-stdlib-jdk7 1.4.21
org_jetbrains_kotlin_kotlin-stdlib-jdk8: kotlin-stdlib-jdk8 1.4.21
org_jetbrains_kotlinx_kotlinx-coroutines-core: kotlinx-coroutines-core 1.3.7
org_jetbrains_kotlinx_kotlinx-coroutines-core-jvm: kotlinx-coroutines-core-jvm 1.4.2
org_jetbrains_kotlinx_kotlinx-coroutines-jdk8: kotlinx-coroutines-jdk8 1.4.2
org_tukaani_xz: xz 1.8
presencefootsteps: Presence Footsteps r29+1.16.4
repurposed_structures: Repurposed Structures 1.16.5-1.8.6
roughlyenoughitems: Roughly Enough Items 5.10.184
roughlyenoughitems-api: REI (API) 5.10.184
roughlyenoughitems-default-plugin: REI (Default Plugin) 5.10.184
roughlyenoughitems-runtime: REI (Runtime) 5.10.184
roughlyenoughresources: Roughly Enough Resources 2.1.3
screenshotclipboard: Screenshot to Clipboard 1.0.6
seamless_loading_screen: Seamless Loading Screen 1.3.1
slight-gui-modifications: 'Slight' GUI Modifications 1.7.1
smoothscrollingeverywhere: Smooth Scrolling Everywhere 3.0.3-unstable
sneak-through-berries: Sneak Through Berries 1.1.0+1.16.4-fabric
sodium: Sodium IRIS-SNAPSHOT
spark: spark 1.4.3
spruceui: SpruceUI 2.0.4+1.16
starlight: Starlight 0.0.3
textile_backup: Textile Backup 2.1.0-prev-1.16.4
the_loved_ones: The Loved Ones 1.1.0+1.16.4
tic_tacs: Tic-TACS 0.1.3
tweakeroo: Tweakeroo 0.10.0-dev.20210303.123654
tweed: Tweed API 3.0.0-beta.22
voyager: Voyager 1.0.0
waila: Hwyla 1.9.22
worldedit: WorldEdit 7.2.0-SNAPSHOT+5279-a8bba3b
worldeditcui: worldeditcui 1.16.1
Perhaps you could use a ConcurrentHashMap if you're using multiple threads? Typical operations still don't require synchronization, so I don't think performance would be a big issue, and a ConcurrentHashMap can be iterated over and modified by different threads.
A ConcurrentHashMap does synchronize internally, also this map is not a map I control(the blockentity map). You are 2 versions behind, the release yesterday hides this exceptions since it's not of relevant(at worst the culling is 10ms outdated, that is less than one frame on a 60hz monitor).
That's my bad, I forgot to mark this mod to be checked for updated by my mod manager.
Wrapping a map with Collections.synchronizedMap()
does synchronize internally on all calls. However, a ConcurrentHashMap
doesn't synchronize on get
s or iteration at all, and only synchronizes on individual bins in the map if the bins aren't empty when a put
is issued.
I don't think a quick @Redirect
for the original map constructor (wherever it is) would be terrible if it means you don't have to use a janky non-deterministic hack like this.
Like I noted in the comment on that code, I don't think there is any value to be gained by using mixins to put a ConcurrentHashMap
into there. I mean it sure can be done, but in the end it's just more stuff to maintain(especially in regards to other mods that might touch that like Lithium) without any visible end user benefits other than it being ever so slightly slower.
The entire culling process is running async to the main thread, so it has to be able to handle stuff unexpectedly changing like the world turning null/chunks not being loaded any more or in this case the block-/entity maps not being async friendly.