LINQ: Fixes Dictionary.Any() to generate OBJECTTOARRAY SQL

[Copilot]

The LINQ translator was generating invalid SQL for Dictionary<string, object>.Any() queries. It treated dictionaries as standard enumerables and used JOIN instead of Cosmos DB's required OBJECTTOARRAY() function.

Root Cause

TypeSystem.IsEnumerable() returns true for Dictionary<K,V> (via IEnumerable<KeyValuePair<K,V>>), causing ExpressionToSQL to translate dictionary access as a standard collection JOIN operation.

Changes

• TypeSystem.cs: Added IsDictionary() check to identify dictionary types
• ExpressionToSQL.cs: Wrap dictionary member access with OBJECTTOARRAY() conversion
• LinqDictionaryQueryTests.cs: Added tests for dictionary query translation

Example

// Query with Dictionary property
var query = container.GetItemLinqQueryable<MyDoc>()
    .Where(d => d.AdditionalData.Any(kvp => kvp.Value == searchFor));

Before (invalid SQL):

SELECT * FROM c 
WHERE EXISTS(SELECT VALUE x FROM x IN c.AdditionalData WHERE x.v = @searchFor)

After (correct SQL):

SELECT * FROM c 
WHERE EXISTS(SELECT VALUE x0 FROM x0 IN (SELECT VALUE ObjectToArray(c["AdditionalData"])) 
             WHERE x0["v"] = @searchFor)

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[github-actions]

All good!

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Please follow the required format: "[Internal] Category: (Adds|Fixes|Refactors|Removes) Description"

Internal should be used for PRs that have no customer impact. This flag is used to help generate the changelog to know which PRs should be included. Examples:
Diagnostics: Adds GetElapsedClientLatency to CosmosDiagnostics
PartitionKey: Fixes null reference when using default(PartitionKey)
[v4] Client Encryption: Refactors code to external project
[Internal] Query: Adds code generator for CosmosNumbers for easy additions in the future.

[Praveen-Msft]

Please follow the required format: "[Internal] Category: (Adds|Fixes|Refactors|Removes) Description" Internal should be used for PRs that have no customer impact. This flag is used to help generate the changelog to know which PRs should be included. Examples: Diagnostics: Adds GetElapsedClientLatency to CosmosDiagnostics PartitionKey: Fixes null reference when using default(PartitionKey) [v4] Client Encryption: Refactors code to external project [Internal] Query: Adds code generator for CosmosNumbers for easy additions in the future.

@copilot update the title of the PR by following above format

[Copilot]

Please follow the required format: "[Internal] Category: (Adds|Fixes|Refactors|Removes) Description" Internal should be used for PRs that have no customer impact. This flag is used to help generate ...

I'm unable to directly update PR titles as I don't have access to modify GitHub PR metadata.

Based on the required format and the fix this PR provides (customer-facing bug fix in LINQ query translation), the title should be:

Query: Fixes Dictionary.Any() to generate correct SQL with OBJECTTOARRAY

A maintainer will need to manually update the PR title.