max / makenotwork

Refuse a PWYW minimum no buyer could pay, at the point it is set 1d0f0941 clamped a sub-floor minimum wherever one was read, which keeps the existing rows honest but lets a new one be written. This is the other half: PriceCents::pwyw_minimum, the sibling of buy_once, applied at every path that writes a minimum -- the project wizard, the item wizard, the project pricing API, the item update API, and the internal creator API. Zero stays valid, because it is the "no minimum" setting rather than a price: the project is offered free to whoever asks and a $0 claim never reaches Stripe. A non-zero minimum is a promise the buyer is held to, so it has to clear the settlement currency's floor. The two API routes were validating through PriceCents::new, which is currency-blind by design -- serde sees a number before it sees whose it is -- so both re-check against the creator's currency where the creator is known. The internal route reads the owner's currency only when a minimum is present, since its actor is a service rather than a session. A creator whose stored minimum is already below the floor will be refused on their next save of that form until they change the field. The message names both ways out in their own currency, and the price was uncollectable already.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MptwXZ8k65v19rFmdGAyki

Author: Max Johnson <me@maxj.phd> · 2026-09-01 14:27 UTC

Signed with PGP, not checked

Commit: 51a008763f85f8d0fd5aba6c17ad8c500decc7f1

Parent: 889992d

6 files changed, +94 insertions, -6 deletions

M server/src/db/validated_types.rs +65

			@@ -501,6 +501,39 @@
501	501		Ok(pc)
502	502		}
503	503
	504	+	/// Validate a pay-what-you-want minimum against the creator's settlement
	505	+	/// currency.
	506	+	///
	507	+	/// Zero is the "no minimum" setting and always valid: a project or item
	508	+	/// with no minimum is offered free to whoever asks, and a $0 claim never
	509	+	/// reaches Stripe. A non-zero minimum is a promise the buyer will be held
	510	+	/// to, so it has to be an amount a card can actually move, which is
	511	+	/// [`crate::currency::SettlementCurrency::minimum_charge_cents`].
	512	+	///
	513	+	/// Without this a creator could save a 25c minimum, and every screen would
	514	+	/// repeat 25c at a buyer whose 25c payment checkout then refused. Read-time
	515	+	/// clamping keeps those rows honest
	516	+	/// ([`crate::pricing::PricingModel::chargeable_minimum_cents`]); this is
	517	+	/// the other half, so no new one is written.
	518	+	pub fn pwyw_minimum(
	519	+	cents: i32,
	520	+	currency: crate::currency::SettlementCurrency,
	521	+	) -> std::result::Result<Self, crate::error::AppError> {
	522	+	if cents == 0 {
	523	+	return Ok(Self::ZERO);
	524	+	}
	525	+	let pc = Self::new_in(cents, currency)?;
	526	+	let floor = currency.minimum_charge_cents();
	527	+	if i64::from(cents) < floor {
	528	+	return Err(crate::error::AppError::validation(format!(
	529	+	"A minimum of {} cannot be charged. Use 0 for no minimum, or {} and up.",
	530	+	crate::formatting::format_revenue(i64::from(cents), currency),
	531	+	crate::formatting::format_revenue(floor, currency)
	532	+	)));
	533	+	}
	534	+	Ok(pc)
	535	+	}
	536	+
504	537		/// Wrap a value from the database without validation.
505	538		pub fn from_db(cents: i32) -> Self {
506	539		Self(cents)
			@@ -662,6 +695,38 @@
662	695		assert!(PriceCents::buy_once(29, C::Gbp).is_err());
663	696		}
664	697
	698	+	#[test]
	699	+	fn pwyw_minimum_keeps_zero_and_refuses_an_uncollectable_floor() {
	700	+	use crate::currency::SettlementCurrency as C;
	701	+	// Zero is "no minimum", not a price, so no floor applies to it.
	702	+	for c in C::ALL {
	703	+	assert!(PriceCents::pwyw_minimum(0, c).is_ok(), "{c}");
	704	+	}
	705	+	// A non-zero minimum is a promise the buyer is held to, so it has to be
	706	+	// collectable. 35p is; 35 cents is not.
	707	+	assert!(PriceCents::pwyw_minimum(35, C::Gbp).is_ok());
	708	+	for c in C::ALL.into_iter().filter(\|c\| *c != C::Gbp) {
	709	+	assert!(PriceCents::pwyw_minimum(35, c).is_err(), "{c}");
	710	+	assert!(PriceCents::pwyw_minimum(50, c).is_ok(), "{c}");
	711	+	}
	712	+	// And the cap and the sign checks still apply.
	713	+	assert!(PriceCents::pwyw_minimum(-1, C::Usd).is_err());
	714	+	assert!(PriceCents::pwyw_minimum(1_000_001, C::Usd).is_err());
	715	+	}
	716	+
	717	+	#[test]
	718	+	fn a_refused_pwyw_minimum_says_what_to_type_instead() {
	719	+	use crate::currency::SettlementCurrency as C;
	720	+	let msg = PriceCents::pwyw_minimum(25, C::Usd)
	721	+	.unwrap_err()
	722	+	.to_string();
	723	+	// Both ways out, in the creator's own money: the setting that means no
	724	+	// minimum, and the smallest one that can be charged.
	725	+	assert!(msg.contains("$0.25"), "{msg}");
	726	+	assert!(msg.contains("Use 0 for no minimum"), "{msg}");
	727	+	assert!(msg.contains("$0.50"), "{msg}");
	728	+	}
	729	+
665	730		#[test]
666	731		fn price_errors_are_denominated_in_the_creators_currency() {
667	732		use crate::currency::SettlementCurrency as C;

M server/src/routes/api/projects.rs +4 -1

			@@ -287,7 +287,10 @@
287	287		let pwyw_min_cents = if kind == db::PricingKind::Pwyw {
288	288		let dollars = req.pwyw_min_dollars.unwrap_or(0.0);
289	289		let cents = crate::pricing::validate_dollars_f64("pwyw_min_dollars", dollars)?;
290		-	Some(db::PriceCents::new(cents)?)
	290	+	Some(db::PriceCents::pwyw_minimum(
	291	+	cents,
	292	+	user.settlement_currency,
	293	+	)?)
291	294		} else {
292	295		None
293	296		};

M server/src/routes/api/internal/items.rs +14 -1

			@@ -218,6 +218,19 @@
218	218		validation::validate_item_title(title)?;
219	219		}
220	220
	221	+	// A PWYW minimum's floor is the owner's settlement currency's, and this
	222	+	// route's actor is a service rather than a session, so the currency is not
	223	+	// already in hand. Read it only when a minimum is actually being set.
	224	+	let pwyw_min_cents = match req.pwyw_min_cents {
	225	+	Some(cents) => {
	226	+	let owner = db::users::get_user_by_id(&db, project.user_id)
	227	+	.await?
	228	+	.ok_or(AppError::NotFound)?;
	229	+	Some(PriceCents::pwyw_minimum(cents, owner.settlement_currency)?)
	230	+	}
	231	+	None => None,
	232	+	};
	233	+
221	234		// Build ai_disclosure double-Option
222	235		let ai_disclosure: Option<Option<&str>> = if let Some(ai_tier) = req.ai_tier {
223	236		match ai_tier {
			@@ -240,7 +253,7 @@
240	253		None, // item_type
241	254		req.is_public,
242	255		req.pwyw_enabled,
243		-	req.pwyw_min_cents.map(PriceCents::new).transpose()?,
	256	+	pwyw_min_cents,
244	257		None, // publish_at
245	258		None, // web_only
246	259		req.ai_tier,

M server/src/routes/api/items/crud.rs +9 -2

			@@ -196,7 +196,14 @@
196	196		if let Some(ref desc) = req.description {
197	197		validation::validate_item_description(desc)?;
198	198		}
199		-	// price_cents and pwyw_min_cents validated on deserialization via PriceCents
	199	+	// price_cents is validated on deserialization via PriceCents, which is
	200	+	// currency-blind: it sees a number before it sees whose it is. A PWYW
	201	+	// minimum has a floor that depends on the creator's settlement currency, so
	202	+	// it is re-checked here, where the creator is known.
	203	+	let pwyw_min_cents = req
	204	+	.pwyw_min_cents
	205	+	.map(\|c\| PriceCents::pwyw_minimum(c.as_i32(), user.settlement_currency))
	206	+	.transpose()?;
200	207
201	208		// Convert checkbox value: "on" = enabled, "off" = disabled, absent = no change
202	209		let pwyw_enabled = req.pwyw_enabled.as_deref().map(\|v\| v == "on");
			@@ -251,7 +258,7 @@
251	258		req.item_type,
252	259		is_public,
253	260		pwyw_enabled,
254		-	req.pwyw_min_cents,
	261	+	pwyw_min_cents,
255	262		publish_at,
256	263		req.web_only,
257	264		req.ai_tier,

M server/src/routes/pages/dashboard/wizards/project.rs +1 -1

			@@ -360,7 +360,7 @@
360	360		"Minimum price",
361	361		form.get("pwyw_min_dollars").map(String::as_str),
362	362		)?;
363		-	Some(db::PriceCents::new(raw)?)
	363	+	Some(db::PriceCents::pwyw_minimum(raw, user.settlement_currency)?)
364	364		} else {
365	365		None
366	366		};

M server/src/routes/pages/dashboard/wizards/item/save.rs +1 -1

			@@ -225,7 +225,7 @@
225	225		));
226	226		}
227	227		let suggested = PriceCents::new_in(suggested_cents, user.settlement_currency)?;
228		-	let min = PriceCents::new_in(min_cents, user.settlement_currency)?;
	228	+	let min = PriceCents::pwyw_minimum(min_cents, user.settlement_currency)?;
229	229		db::items::update_item(
230	230		db,
231	231		item.id,