tests: add false positive gosec G117 case

[adamdecaf]

Issue: securego/gosec#1614

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a new test case designed to highlight and reproduce a false positive detection within the gosec static analysis tool. The added code illustrates a common pattern of handling sensitive data during JSON serialization by masking it in a custom MarshalJSON implementation, which gosec currently misinterprets as a direct exposure of sensitive information. This change aims to provide a concrete example for improving the accuracy of gosec's vulnerability detection logic.

Highlights

• New Test Case for Gosec G117: A new test file, tests/code/gosec_G117.go, has been added to specifically reproduce a false positive scenario for the G117 rule in the gosec static analysis tool.
• False Positive Reproduction: The test case demonstrates a situation where a Credentials struct with a sensitive Password field, which is masked via a custom MarshalJSON method before serialization, is incorrectly flagged by gosec as a G117 vulnerability.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Changelog

• tests/code/gosec_G117.go
  • Added a new Go file to include a test case for a false positive in gosec's G117 rule.

Activity

• The pull request was created by adamdecaf.
• A new file tests/code/gosec_G117.go was added to the repository.
• The changes address issue G117 - false positive even when masked securego/gosec#1614.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request adds a test case for a gosec false positive (G117) related to custom JSON marshaling of sensitive fields. The implementation is sound, but I have a couple of minor suggestions to improve code clarity and adhere to common Go idioms.

[gemini-code-assist]

For improved conciseness, you can use an anonymous struct directly within the json.Marshal call. This is a common Go idiom for custom JSON marshalers and avoids defining a named type (Aux) that is only used once in this scope.

return json.Marshal(struct {
		Username string
		Password string
	}{
		Username: c.Username,
		Password: mask(c.Password),
	})

[gemini-code-assist]

The input parameter is unused within the function. In Go, it's idiomatic to use the blank identifier _ for unused parameters to make it explicit that they are intentionally ignored. This improves code clarity and satisfies linters that check for unused variables.

func mask(_ string) string {