Fetch image builder version from Modal settings

[ehdr]

Note

Both SDKs now fetch and cache environment settings and use the server-provided Image Builder Version for image builds, replacing hardcoded defaults and updating calls to pass the resolved environment.

• Breaking change:
  • SDKs read Image Builder Version from account settings instead of defaulting to 2024.10 (may trigger one rebuild on first run).
• Go SDK:
  • Environment settings: Add environment.go with Environment model, cached fetch (sync.Map + singleflight) via EnvironmentGetOrCreate and imageBuilderVersion(ctx, env).
  • Image builds: Image.Build() uses server-derived builderVersion and logs builder_version/env_name.
  • Environment resolution: Replace environmentName() with firstNonEmpty(..., profile.Environment) across services (Apps, Cls, Functions, Proxy, Queue, Volume, Sandbox, Secret).
  • Client: Track environmentsCache and environmentGroup.
• JS SDK:
  • Environment settings: Add environment fetch/caching in ModalClient (fetchEnvironment, getImageBuilderVersion) via environmentGetOrCreate.
  • Image builds: Image.build() uses server-derived builderVersion and logs builder_version/env_name.
• Tests:
  • Add environment caching/precedence tests in Go and JS.
  • Update image-related tests to set MODAL_IMAGE_BUILDER_VERSION where needed; vitest sets default env var.
• Docs:
  • Update CHANGELOG.md to note breaking change.

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[cursor]

Bug: Missing fallback for empty server image builder version

The new imageBuilderVersion function returns whatever the server provides, which could be an empty string if EnvironmentSettings.ImageBuilderVersion is not set. The old implementation had a hardcoded fallback of "2024.10" when both the profile and server-provided values were empty. Without this fallback, image builds may receive an empty builderVersion, potentially causing undefined behavior if the server doesn't guarantee this field is always populated.

Additional Locations (1)

• modal-js/src/client.ts#L225-L233