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SamuelFrostSamuelFrost
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Document override extendsMergeMode as full top-level replace
Align spec and schema with spread semantics: set properties replace the inherited value entirely; omitted properties keep the chain below.
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‎docs/specs/devcontainerjson-reference.md‎

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@@ -73,11 +73,10 @@ Uses the same [merge logic](devcontainer-reference.md#merge-logic) applied to im
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### `extendsMergeMode`: `override`
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Uses overlay-style merging when the current file should replace rather than combine with the base:
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Uses overlay-style merging when the current file should replace inherited values rather than combine with the base (`{ ...base, ...current }`):
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- Arrays and scalars from the current file replace the base when set on the current file (for example, `forwardPorts` is only the current file's list).
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- Object maps and `hostRequirements` are shallow-merged per key, with the current file winning on conflicts.
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- Boolean `init` and `privileged` use the current file's value when set.
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- Each top-level property set on the current file fully replaces the inherited value (arrays, object maps, `hostRequirements`, scalars, and booleans).
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- Top-level properties omitted on the current file keep the value from the referenced configuration chain.
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Neither `extends` nor `extendsMergeMode` is present in the merged result.
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‎schemas/devContainer.base.schema.json‎

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"combine",
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"override"
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],
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"description": "How to merge the referenced extends file with this file. combine (default) uses the image metadata merge logic. override replaces arrays and scalars from this file and shallow-merges object maps and hostRequirements."
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"description": "How to merge the referenced extends file with this file. combine (default) uses the image metadata merge logic. override uses spread semantics: each top-level property set on this file fully replaces the inherited value; omitted properties keep the inherited value."
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},
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"features": {
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"type": "object",

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