infer_clone/website/docs/checker-inefficient-keyset-...

---
title: "Inefficient keySet Iterator"
description: "Check for inefficient uses of iterators that iterate on keys then lookup their values, instead of iterating on key-value pairs directly."
---

Check for inefficient uses of iterators that iterate on keys then lookup their values, instead of iterating on key-value pairs directly.

Activate with `--inefficient-keyset-iterator`.

Supported languages:
- C/C++/ObjC: No
- Java: Yes


## List of Issue Types

The following issue types are reported by this checker:
- [INEFFICIENT_KEYSET_ITERATOR](/docs/next/all-issue-types#inefficient_keyset_iterator)
[website] make doc-publish Summary: New website! Now with one page per checker, and only one page containing all issue types for easy tooling. Each checker page also lists the issue types it can report. For now only issue types with documentation appear in either page, filling these up is still TODO. Reviewed By: mityal Differential Revision: D21934465 fbshipit-source-id: 82ae1e417 5 years ago			`---`
			`title: "Inefficient keySet Iterator"`
			`description: "Check for inefficient uses of iterators that iterate on keys then lookup their values, instead of iterating on key-value pairs directly."`
			`---`

			`Check for inefficient uses of iterators that iterate on keys then lookup their values, instead of iterating on key-value pairs directly.`

			Activate with `--inefficient-keyset-iterator`.

			`Supported languages:`
			`- C/C++/ObjC: No`
			`- Java: Yes`

make doc-publish Summary: Needed to remove user_documentation for the new CONFIG_CHECK_BETWEEN_MARKERS issue type otherwise it violated the invariant that the corresponding checker should be documented too but its development has just started. Reviewed By: skcho Differential Revision: D22065820 fbshipit-source-id: 4b3a58850 5 years ago

			`## List of Issue Types`

			`The following issue types are reported by this checker:`
[website] make docs URLs absolute Summary: A bug in docusaurus makes relative URLs fail depending on how the page was accessed, because the URL of a page in docs/ will end in / if accessed directly or via hyperlink, but that / will be omitted when clicking on the sidebar. The final / makes all the difference when interpreting relative URLs so relative URLs are essentially broken. See https://github.com/facebook/docusaurus/issues/2832 for more details. This changes URL generation to generate URLs /docs/next/..., and manually substitute relative URLs that had been written by hand. Also fix a few other things about outdated links/comments. Finally, `make doc-publish`. Reviewed By: dulmarod Differential Revision: D22117187 fbshipit-source-id: 32e2ba7e1 5 years ago			`- [INEFFICIENT_KEYSET_ITERATOR](/docs/next/all-issue-types#inefficient_keyset_iterator)`