perf(dotnet): optimize dictionary lookups in model Equals methods

[daniel-jonathan]

Optimize Dictionary Lookups in Model Equals Methods

Problem

The generated model Equals methods perform inefficient dictionary comparisons for AdditionalProperties:

input.AdditionalProperties.ContainsKey(kv.Key) && Equals(kv.Value, input.AdditionalProperties[kv.Key])

This performs two dictionary lookups per key:

1. ContainsKey(kv.Key) - checks if key exists
2. input.AdditionalProperties[kv.Key] - retrieves the value

CodeQL Warning

Source: CodeQL static analysis on openfga/dotnet-sdk#156

Warning: "Inefficient use of ContainsKey and indexer"

Impact: Performance penalty on every equality check for models with AdditionalProperties

Solution

Use TryGetValue which performs both operations in a single dictionary lookup:

input.AdditionalProperties.TryGetValue(kv.Key, out var inputValue) && Equals(kv.Value, inputValue)

Changes

File: config/clients/dotnet/template/modelGeneric.mustache line 357

Before:

&& (this.AdditionalProperties.Count == input.AdditionalProperties.Count && this.AdditionalProperties.All(kv => input.AdditionalProperties.ContainsKey(kv.Key) && Equals(kv.Value, input.AdditionalProperties[kv.Key])));

After:

&& (this.AdditionalProperties.Count == input.AdditionalProperties.Count && this.AdditionalProperties.All(kv => input.AdditionalProperties.TryGetValue(kv.Key, out var inputValue) && Equals(kv.Value, inputValue)));

Impact

This optimization applies to all generated models with AdditionalProperties, including:

• All 79+ model files in the dotnet SDK
• Future model generations
• Reduces O(2) dictionary operations to O(1)

Testing

Verified that the generated code:

• Builds successfully with 0 errors
• Maintains identical equality semantics
• Resolves CodeQL warning
• Follows C# best practices

References

• CodeQL analysis: feat: add StreamedListObjects support dotnet-sdk#156
• C# best practice: Use TryGetValue instead of ContainsKey + indexer
• Performance: https://stackoverflow.com/questions/9382681/what-is-more-efficient-dictionary-trygetvalue-or-containskeyitem

Files Modified

• config/clients/dotnet/template/modelGeneric.mustache

Summary by CodeRabbit

• Refactor
  • Optimized object comparison logic for improved performance.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

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Walkthrough

A .NET template file was modified to refactor the Equals method's AdditionalProperties comparison logic. The implementation changed from using ContainsKey and key lookup to using TryGetValue within a lambda expression for retrieving and comparing property values.

Changes

Cohort / File(s)	Summary
Equals method comparison refactoring config/clients/dotnet/template/modelGeneric.mustache	Modified AdditionalProperties equality check to use TryGetValue instead of ContainsKey with direct key lookup; introduces local variable for retrieved value comparison

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Verify that TryGetValue properly replaces the ContainsKey + lookup pattern without behavioral changes
• Confirm the null-check logic and comparison semantics remain equivalent to the original implementation
• Check template syntax validity and proper escaping for Mustache templating

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and accurately summarizes the main change: optimizing dictionary lookups in .NET model Equals methods by replacing ContainsKey+indexer with TryGetValue.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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