fix(linter): fix stack overflow in no-unreachable rule on large files

[Boshen]

Summary

• Convert set_depth_first_search in oxc_cfg from recursive to iterative implementation using an explicit stack
• Update no-unreachable rule to use the iterative DFS instead of petgraph's recursive depth_first_search

This fixes stack overflow when linting large files with many basic blocks in the control flow graph.

Closes #11250

Test plan

• All 916 linter tests pass
• Verified fix with reduced stack size: RUST_MIN_STACK=262144 ./target/debug/oxlint -A all -D no-unreachable large_file.js
• Also tested with 128KB stack size successfully

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes a stack overflow issue in the no-unreachable linter rule when processing large files by converting the depth-first search implementation from recursive to iterative.

Changes:

• Converted set_depth_first_search function in crates/oxc_cfg/src/visit.rs from a recursive to an iterative implementation using an explicit stack
• Updated no-unreachable rule to import set_depth_first_search instead of petgraph's depth_first_search

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
crates/oxc_linter/src/rules/eslint/no_unreachable.rs	Updated imports to use the iterative set_depth_first_search implementation
crates/oxc_cfg/src/visit.rs	Replaced recursive DFS with iterative implementation using explicit stack to prevent stack overflow

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[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 41 skipped benchmarks¹

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_{Comparing fix/no-unreachable-stack-overflow (544e353) with main (b516088)²}

Footnotes

1. 41 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (40ef7ee) during the generation of this report, so b516088 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[camc314]

Merge activity

• Jan 16, 12:32 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Jan 16, 12:32 PM UTC: camc314 added this pull request to the Graphite merge queue.
• Jan 16, 12:39 PM UTC: Merged by the Graphite merge queue.