`src/shared/uniswap.js` gated the token and the amount on truthiness, and
gated them independently. An address is never falsy once set, but an amount
of `0n` is, so a hop supplying a zero amount fixed the token permanently
while leaving the amount open, and the next hop's figure was then displayed
against the first hop's token, at that token's scale.
Input side: a V3 `USDT -> WETH` hop with `amountIn = 0n` followed by a V2
`WETH -> USDC` hop of `0.5e18` rendered `Token In = USDT` with
`Amount = 500000000000.0000 USDT`. Output side: a V3 hop followed by a V4
step with `amountOutMin = 0n` kept `Min. received = 0.5000 WETH` on screen
for a final leg that guarantees nothing.
Both halves are the same gate in the same file and take the same remedy, so
they are one change rather than two statements of one rule.
- One `present()` helper replaces every truthiness gate on a decoded value.
- The input and output sides are each set as a PAIR, never field by field:
an amount and the token it is counted in always come from the same hop.
The input side is fixed by the first hop that states either half, the
output side by the last. A half the establishing hop did not state stays
null and the line says so.
- A zero slippage floor reads `None (no minimum guaranteed)` rather than
`0.0000`, which reads as an artifact of the four-decimal rule.
- A V4 `amountIn` of zero is `ActionConstants.OPEN_DELTA` -- v4-periphery's
`V4Router` substitutes the full open credit for it -- so it reads
`All available (V4 open delta)`, not `0.0000`, which would have stated the
exact inverse of what the step does. `amountOutMinimum` gets no such
mapping and a zero there is a literal floor of zero.
Tests: the two fail-first cases from the issues, two further pairing cases
(a zero minimum against a named output token, and a final leg naming a token
but no minimum), the open-delta amount, and the PERMIT2_PERMIT-only
`execute()` that must invent no output token. Native ETH is pinned on both
sides against the real mainnet fixture and the WRAP_ETH/UNWRAP_WETH paths.
closes#364
sneak
bbfbe885cd