Improve pattern matching for GasPrice.fromString in @cosmjs/launchpad

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to
 - @cosmjs/launchpad, @cosmjs/stargate: Avoid the use of named capture groups in
   `GasPrice.fromString` to restore ES2017 compatibility and make the library
   work with Hermes ([#801]; thanks [@AlexBHarley]).
+- @cosmjs/launchpad: Adapt `GasPrice.fromString` denom pattern to Cosmos SDK
+  0.39 rules: reduce denom length to 16 and allow digits in denom.
 
 [#800]: https://github.com/cosmos/cosmjs/issues/800
 [#801]: https://github.com/cosmos/cosmjs/issues/801

packages/launchpad/src/fee.spec.ts

@@ -14,12 +14,21 @@ describe("GasPrice", () => {
 
   describe("fromString", () => {
     it("works", () => {
-      const inputs = ["3.14", "3", "0.14"];
-      inputs.forEach((input) => {
-        const gasPrice = GasPrice.fromString(`${input}utest`);
-        expect(gasPrice.amount.toString()).toEqual(input);
-        expect(gasPrice.denom).toEqual("utest");
-      });
+      const inputs: Record<string, { amount: string; denom: string }> = {
+        // Test amounts
+        "3.14utest": { amount: "3.14", denom: "utest" },
+        "3utest": { amount: "3", denom: "utest" },
+        "0.14utest": { amount: "0.14", denom: "utest" },
+        // Test denoms
+        "0.14sht": { amount: "0.14", denom: "sht" },
+        "0.14testtesttesttest": { amount: "0.14", denom: "testtesttesttest" },
+        "0.14ucoin2": { amount: "0.14", denom: "ucoin2" },
+      };
+      for (const [input, expected] of Object.entries(inputs)) {
+        const gasPrice = GasPrice.fromString(input);
+        expect(gasPrice.amount.toString()).withContext(`Input: ${input}`).toEqual(expected.amount);
+        expect(gasPrice.denom).withContext(`Input: ${input}`).toEqual(expected.denom);
+      }
     });
 
     it("errors for invalid gas price", () => {
@@ -30,17 +39,14 @@ describe("GasPrice", () => {
       expect(() => GasPrice.fromString("234")).toThrowError(/Invalid gas price string/i);
       expect(() => GasPrice.fromString("-234tkn")).toThrowError(/Invalid gas price string/i);
       // Checks details of <denom>
-      expect(() => GasPrice.fromString("234t")).toThrowError(
-        /denomination must be between 3 and 127 characters/i,
+      expect(() => GasPrice.fromString("234t")).toThrowError(/denom must be between 3 and 16 characters/i);
+      expect(() => GasPrice.fromString("234tt")).toThrowError(/denom must be between 3 and 16 characters/i);
+      expect(() => GasPrice.fromString("234ttttttttttttttttt")).toThrowError(
+        /denom must be between 3 and 16 characters/i,
       );
-      expect(() => GasPrice.fromString("234tt")).toThrowError(
-        /denomination must be between 3 and 127 characters/i,
+      expect(() => GasPrice.fromString("234ATOM")).toThrowError(
+        /denom must only contain lower case letters a-z and digits 0-9/i,
       );
-      expect(() =>
-        GasPrice.fromString(
-          "234tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt",
-        ),
-      ).toThrowError(/denomination must be between 3 and 127 characters/i);
       // Checks details of <amount>
       expect(() => GasPrice.fromString("3.utkn")).toThrowError(/Fractional part missing/i);
       expect(() => GasPrice.fromString("..utkn")).toThrowError(/More than one separator found/i);

packages/launchpad/src/fee.ts

@@ -3,6 +3,21 @@ import { Decimal, Uint53 } from "@cosmjs/math";
 
 export type FeeTable = Record<string, StdFee>;
 
+/**
+ * Denom checker for the Cosmos SDK 0.39 denom pattern
+ * (https://github.com/cosmos/cosmos-sdk/blob/v0.39.3/types/coin.go#L597-L598).
+ *
+ * This is like a regexp but with helpful error messages.
+ */
+function checkDenom(denom: string): void {
+  if (denom.length < 3 || denom.length > 16) {
+    throw new Error("Denom must be between 3 and 16 characters");
+  }
+  if (denom.match(/[^a-z0-9]/)) {
+    throw new Error("Denom must only contain lower case letters a-z and digits 0-9");
+  }
+}
+
 /**
  * A gas price, i.e. the price of a single gas. This is typically a fraction of
  * the smallest fee token unit, such as 0.012utoken.
@@ -18,16 +33,18 @@ export class GasPrice {
 
   /**
    * Parses a gas price formatted as `<amount><denom>`, e.g. `GasPrice.fromString("0.012utoken")`.
+   *
+   * The denom must match the Cosmos SDK 0.39 pattern (https://github.com/cosmos/cosmos-sdk/blob/v0.39.3/types/coin.go#L597-L598).
+   * See `GasPrice` in @cosmjs/stargate for a more generic matcher.
    */
   public static fromString(gasPrice: string): GasPrice {
-    const matchResult = gasPrice.match(/^([0-9.]+?)([a-z]+)$/);
+    // Use Decimal.fromUserInput and checkDenom for detailed checks and helpful error messages
+    const matchResult = gasPrice.match(/^([0-9.]+)([a-z][a-z0-9]*)$/i);
     if (!matchResult) {
       throw new Error("Invalid gas price string");
     }
     const [_, amount, denom] = matchResult;
-    if (denom.length < 3 || denom.length > 127) {
-      throw new Error("Gas price denomination must be between 3 and 127 characters");
-    }
+    checkDenom(denom);
     const fractionalDigits = 18;
     const decimalAmount = Decimal.fromUserInput(amount, fractionalDigits);
     return new GasPrice(decimalAmount, denom);