Move graph cycle detection to rust. (cherrypick of #11202) #11203
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Our existing cycle detection (and reporting) algorithm is implemented recursively in Python, and can hit recursion depth limits for larger graphs. Rather than porting to an iterative algorithm (which is complex when you need to actually report the cycle path), or adjusting recursion limits (which would work fine, but which exist as a reminder that stack frames are not cheap in Python), port our existing algorithm to Rust. Fixes pantsbuild#11201. [ci skip-build-wheels]
Eric-Arellano
approved these changes
Nov 19, 2020
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Problem
Our existing cycle detection (and reporting) algorithm is implemented recursively in Python, and can hit recursion depth limits for larger graphs.
Solution
Rather than porting to an iterative algorithm (which is complex when you need to actually report the cycle path), or adjusting recursion limits (which would work fine, but which exist as a reminder that stack frames are not cheap in Python), port our existing algorithm to Rust.
Fixes #11201.
[ci skip-build-wheels]