xianny
24 lines
647 B
Markdown
24 lines
647 B
Markdown
---
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title: Exceptional ERC20s
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---
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Some ERC20s have unique behavior that may require extra handling. We
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document these here as they are discovered.
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# Assert vs Require
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These ERC20\'s use [assert]{.title-ref} instead of
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[require]{.title-ref}, which means that if the token reverts then
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(nearly) all of the gas from your transaction will be consumed.
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Specifically, you are left with 1/64 of the gas limit. Be mindful of
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this when implementing fallback logic; for example, if a call to
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[transferFrom]{.title-ref} reverts then note you will only have 1/64 of
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the gas limit to handle the exception.
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Known tokens:
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- KNC
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- LINK
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- sUSD
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- USDT
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