fix(escrow): unbounded u128

crates/bin/escrow_manager/src/contracts.rs

@@ -84,14 +84,17 @@ impl Contracts {
         *self.graph_tally_collector.address()
     }
 
+    /// Saturates at `u128::MAX`. An unlimited approval (`U256::MAX`) doesn't fit in `u128`, and the
+    /// only thing done with this value is comparing it against the configured allowance, which any
+    /// saturated value clears. Returning an error here instead bricked the whole process on startup.
     pub async fn allowance(&self) -> anyhow::Result<u128> {
-        self.token
+        let allowance = self
+            .token
             .allowance(self.payer(), *self.payments_escrow.address())
             .call()
             .await
-            .context("get allowance")?
-            .try_into()
-            .context("result out of bounds")
+            .context("get allowance")?;
+        Ok(u128::try_from(allowance).unwrap_or(u128::MAX))
     }
 
     pub async fn approve(&self, amount: u128) -> anyhow::Result<()> {

crates/bin/escrow_manager/src/main.rs

@@ -134,7 +134,7 @@ async fn main() -> anyhow::Result<()> {
 
     let mut allowance = contracts.allowance().await?;
     let expected_allowance = config.grt_allowance as u128 * GRT;
-    tracing::info!(allowance = allowance as f64 * 1e-18);
+    tracing::info!(allowance = %format_allowance(allowance));
     if allowance < expected_allowance {
         if config.dry_run {
             tracing::info!(
@@ -147,7 +147,7 @@ async fn main() -> anyhow::Result<()> {
                 .await
                 .context("approve")?;
             allowance = contracts.allowance().await?;
-            tracing::info!(allowance = allowance as f64 * 1e-18);
+            tracing::info!(allowance = %format_allowance(allowance));
         }
     }
 
@@ -493,6 +493,15 @@ async fn main() -> anyhow::Result<()> {
     }
 }
 
+/// `u128::MAX` is what `Contracts::allowance` saturates an unlimited on-chain approval to. Printed
+/// as GRT it reads as 3.4e20, which looks like a real (absurd) number rather than "no limit set".
+fn format_allowance(allowance: u128) -> String {
+    match allowance {
+        u128::MAX => "unlimited".to_string(),
+        allowance => format!("{}", allowance as f64 * 1e-18),
+    }
+}
+
 /// Target escrow balance for a receiver with the given debt. The balance steps up while debt
 /// reaches `fill_factor` of the current step, so the target settles at roughly `debt / fill_factor`
 /// once the steps are fine-grained (above `MAX_ADJUSTMENT`, where they stop doubling).