fix(map): validate map subdocument when loaded with init

[AbdelrahmanHafez]

Fixes #15957

When a document with nested Maps is loaded from the db via findOne() etc., validate() silently passes even for invalid data.

The issue is in _getPathsToValidate(), which has an optimization that removes paths with no validators. SchemaMap has no direct validators, so map paths were getting removed entirely before validation could recurse into subdocuments.

The reason constructor-created docs worked fine is they track paths like myMap.someKey in activePaths.modify, which gets validated through SchemaSubdocument. But init only tracks myMap in activePaths.init, which was getting skipped by the optimization.

Fix: skip the optimization for SchemaMap paths. The existing $* schema path (SchemaSubdocument) already handles recursive validation of map entries and their nested subdocuments, so no additional doValidate method was needed.

[Copilot]

Pull request overview

This PR fixes a bug where validation silently passes for invalid nested map subdocuments when documents are loaded from the database via findOne() or similar methods. The issue occurred because _getPathsToValidate() has an optimization that removes paths with no validators, and SchemaMap itself has no direct validators. Additionally, SchemaMap lacked a doValidate method to validate subdocuments within the map.

Changes:

• Added doValidate method to SchemaMap to validate subdocuments in map values
• Modified _getPathsToValidate() to skip the validator optimization for SchemaMap types
• Added test case to verify nested map subdocument validation after initialization

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

File	Description
lib/schema/map.js	Added doValidate method to validate subdocuments in map values when the map contains schemas with $isSingleNested flag
lib/document.js	Modified validation path optimization to exclude SchemaMap types, ensuring maps are always validated even without direct validators
test/types.map.test.js	Added test case for validating nested map subdocuments loaded via init() with invalid data

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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[hasezoey]

LGTM

[vkarpov15]

Thanks 👍