Calls inside a loop.md

43 - Calls inside a loop

Calls to external contracts inside a loop are dangerous (especially if the loop index can be user-controlled) because it could lead to DoS if one of the calls reverts or execution runs out of gas. Avoid calls within loops, check that loop index cannot be user-controlled or is bounded. (see here)

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Slide Screenshot

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Slide Text

• External Calls Inside Loops
• Loop Index User Controlled
• Reverts -> Out-of-Gas Error
• Avoid Calls in Loops
• Prevent DoS

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References

• Youtube Reference

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