docs: document build memory limits and container env var behaviour - #589
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Both of these came out of a user hitting them live in Discord and losing time to guesswork, and neither was written down anywhere. Container memory: GameCI caps the container at a percentage of host memory (95% Linux, 80% Windows, 75% elsewhere), so a Windows build on a 16GB GitHub runner silently gets ~12.8GB with ~3GB left unused. That is a reasonable default, but when an IL2CPP/Burst build dies with an LLVM out-of-memory there was nothing telling you dockerMemoryLimit was the knob, or that peak memory is driven mostly by parallelism - which matters disproportionately for DOTS/ECS projects, where Burst AOT rather than IL2CPP is often the real consumer. Env vars: the container inherits a fixed allowlist, not the workflow environment, so setting something like IL2CPP_ADDITIONAL_ARGS in `env:` is silently dropped at the container boundary. This is genuinely surprising - it looks like it should work - and the fix (pass it via customParameters and read it with Environment.GetCommandLineArgs) is not obvious either. Also documents dockerShmSize, which had no reference entry at all despite being the documented remedy for "Insufficient shared memory available" on Unity 6.6+. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Included review availability: Your plan provides up to 2 included reviews per hour; 0 remain after this review. 📝 WalkthroughWalkthroughThe documentation adds Builder configuration options for Docker shared memory, environment forwarding, Unity settings, strict validation, and ChangesDocumentation updates
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In `@docs/09-troubleshooting/common-issues.mdx`:
- Line 382: Update the memory guidance example by removing the unsupported
-maxConcurrentImport parameter and replacing it with the supported Asset
Pipeline setting “Desired Import Worker Count.”
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Shows the customParameters + buildMethod injection pattern end to end, including why IL2CPP_ADDITIONAL_ARGS specifically cannot be used (env vars do not reach the container) and PlayerSettings.SetAdditionalIl2CppArgs is the route instead. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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In `@docs/09-troubleshooting/common-issues.mdx`:
- Around line 443-444: Update the import worker count assignments to use
EditorUserSettings instead of EditorSettings, including desiredImportWorkerCount
and standbyImportWorkerCount, so CiBuild.Build compiles with Unity 6.
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The "environment variables don't reach Unity" section previously offered customParameters as the only workaround. That is still the right answer for Unity command line arguments, but it cannot set an environment variable - which is exactly what Unity's own IL2CPP_ADDITIONAL_ARGS and similar toolchain knobs read. dockerEnv (game-ci/cli#261) closes that gap, so lead with it and keep customParameters as the argument-passing alternative, with a note on when each applies. Also documents the GAME_CI_* prefix (game-ci/cli#262): every CLI option is settable as an environment variable, which is how a workflow reaches options the action has no matching input for. Records the precedence (input > env > default) and the reserved-namespace tradeoff. Cross-reference anchors verified against the built HTML rather than assumed. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
…isms Two errors in the parallelism worked example, both caught by asking what covers settings other than IL2CPP: 1. desiredImportWorkerCount and standbyImportWorkerCount are on EditorUserSettings, not EditorSettings. The sample as written would not compile - and it is code we are inviting people to copy. 2. The section claimed IL2CPP_ADDITIONAL_ARGS "cannot be used" because env vars do not reach the container. That was true when written and is no longer: dockerEnv (game-ci/cli#261) forwards them explicitly. Adds a table separating the three mechanisms, because they are not interchangeable and the difference is not guessable: env-var settings go through dockerEnv, editor command line settings (-job-worker-count, -gc-helper-count) through customParameters, and editor-API-only settings need a build method. Asset import workers are specifically called out as having no command line or environment equivalent at all - a Unity constraint rather than a GameCI one, and the reason the editor script in this example exists. Every API name and command line argument here verified against Unity's 6000.0 scripting reference rather than carried over from the previous draft. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Completes the three-mechanism picture. The table previously sent people writing their own build method for anything Unity exposes only as an Editor scripting API - asset import worker counts being the case with no command line argument and no environment variable at all. game-ci/cli#263 applies those APIs directly, so the table's last two rows now point at unitySettings instead of at hand-written C#. Documents both forms (assignment and invocation), the reflection-based resolution that means there is no fixed list of supported settings, the CI-only application, and the lenient-by-default failure behaviour with unitySettingsStrict as the opt-in. Anchors verified against the built HTML. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Inline comments:
In `@docs/09-troubleshooting/common-issues.mdx`:
- Line 419: Remove the IL2CPP_ADDITIONAL_ARGS example value --maxcpucount=2 from
all referenced troubleshooting examples, including the entries near the existing
configuration examples. Do not replace it with an undocumented option; only use
a documented platform-specific parallelism control if one already exists.
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CodeRabbit flagged --maxcpucount as unsupported and it is right, for a more specific reason than "undocumented". Unity's own reference for SetAdditionalIl2CppArgs states the contents are "passed directly to the C++ compiler with no interpretation" and that "valid compiler flags depend on the platform you are building for and the C++ compiler used by IL2CPP on that platform". --maxcpucount is an MSBuild option, not a clang or MSVC flag, so this channel is the wrong destination for it - and Unity warns the same feature carries "a high risk of breaking builds" and is experimental. Removes all six occurrences rather than the one that was flagged: the same example had been copied into the builder reference, the dockerEnv section, the unitySettings section, the GAME_CI_* section and the CiBuild.cs sample. The parallelism guidance now uses only controls verified against Unity's 6000.0 reference: -job-worker-count, EditorUserSettings import worker counts, and Il2CppCodeGeneration.OptimizeSize. dockerEnv examples use a neutral variable, since the mechanism is what they illustrate and they do not need to make a Unity claim to do it. Adds a note explaining what IL2CPP_ADDITIONAL_ARGS actually feeds, so readers who find the widespread advice elsewhere understand why it is not repeated here. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Summary
Two undocumented behaviours that a user hit live in Discord and lost real time to, plus one missing reference entry.
1. Build runs out of memory (new troubleshooting section)
GameCI caps the container's memory at a percentage of host memory — 95% on Linux, 80% on Windows, 75% elsewhere (
defaultDockerMemoryLimit()in the CLI). On a standard 16 GB GitHub-hosted Windows runner that means the build gets ~12.8 GB with ~3 GB left unused, and nothing anywhere told youdockerMemoryLimitwas the knob to reclaim it.The section also covers the part that actually dominates peak memory — parallelism — and calls out that this hits DOTS/ECS projects disproportionately, since Burst AOT rather than IL2CPP is often the real consumer there. Includes the pattern for applying CI-only settings without changing committed Project Settings (editor script +
customParameters+buildMethod).2. Environment variables don't reach the container (new troubleshooting section)
The container inherits a fixed allowlist, not the workflow environment. So setting something like
IL2CPP_ADDITIONAL_ARGSinenv:is silently dropped at the container boundary — it looks like it should work, and there's no error to tell you otherwise. Documents what is forwarded, why, and thatcustomParametersis the reliable route.3.
dockerShmSizereference entry (was missing entirely)It had no entry in the builder reference at all, despite being the documented remedy for
Insufficient shared memory availableon Unity 6.6+.Test plan
yarn oxfmt --checkpasses on both changed files (the repo-wide check reports pre-existing issues across 389 files, untouched here)#dockermemorylimit,#customparameters,#buildmethod1025mshm default all read fromgame-ci/clidirectly🤖 Generated with Claude Code
Summary by CodeRabbit
dockerEnv,unitySettings, andunitySettingsStrict, including supported syntax and strict failure behavior.