Trap CALL_EXCEPTION errors when resolving ENS entries (#1690).

ethers-io · Jun 22, 2021 · 91951dc · 91951dc
1 parent 8277f5a
commit 91951dc
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Showing 3 changed files with 54 additions and 21 deletions.
diff --git a/packages/providers/src.ts/base-provider.ts b/packages/providers/src.ts/base-provider.ts
@@ -250,19 +250,23 @@ export class Resolver implements EnsResolver {
     }
 
     async _fetchBytes(selector: string, parameters?: string): Promise<string> {
-
         // keccak256("addr(bytes32,uint256)")
         const transaction = {
             to: this.address,
             data: hexConcat([ selector, namehash(this.name), (parameters || "0x") ])
         };
 
-        const result = await this.provider.call(transaction);
-        if (result === "0x") { return null; }
+        try {
+            const result = await this.provider.call(transaction);
+            if (result === "0x") { return null; }
 
-        const offset = BigNumber.from(hexDataSlice(result, 0, 32)).toNumber();
-        const length = BigNumber.from(hexDataSlice(result, offset, offset + 32)).toNumber();
-        return hexDataSlice(result, offset + 32, offset + 32 + length);
+            const offset = BigNumber.from(hexDataSlice(result, 0, 32)).toNumber();
+            const length = BigNumber.from(hexDataSlice(result, offset, offset + 32)).toNumber();
+            return hexDataSlice(result, offset + 32, offset + 32 + length);
+        } catch (error) {
+            if (error.code === Logger.errors.CALL_EXCEPTION) { return null; }
+            return null;
+        }
     }
 
     _getAddress(coinType: number, hexBytes: string): string {
@@ -332,17 +336,22 @@ export class Resolver implements EnsResolver {
 
         // If Ethereum, use the standard `addr(bytes32)`
         if (coinType === 60) {
-            // keccak256("addr(bytes32)")
-            const transaction = {
-                to: this.address,
-                data: ("0x3b3b57de" + namehash(this.name).substring(2))
-            };
-            const hexBytes = await this.provider.call(transaction);
+            try {
+                // keccak256("addr(bytes32)")
+                const transaction = {
+                    to: this.address,
+                    data: ("0x3b3b57de" + namehash(this.name).substring(2))
+                };
+                const hexBytes = await this.provider.call(transaction);
 
-            // No address
-            if (hexBytes === "0x" || hexBytes === HashZero) { return null; }
+                // No address
+                if (hexBytes === "0x" || hexBytes === HashZero) { return null; }
 
-            return this.provider.formatter.callAddress(hexBytes);
+                return this.provider.formatter.callAddress(hexBytes);
+            } catch (error) {
+                if (error.code === Logger.errors.CALL_EXCEPTION) { return null; }
+                throw error;
+            }
         }
 
         // keccak256("addr(bytes32,uint256")
@@ -1499,9 +1508,14 @@ export class BaseProvider extends Provider implements EnsProvider {
 
 
     async getResolver(name: string): Promise<Resolver> {
-        const address = await this._getResolver(name);
-        if (address == null) { return null; }
-        return new Resolver(this, address, name);
+        try {
+            const address = await this._getResolver(name);
+            if (address == null) { return null; }
+            return new Resolver(this, address, name);
+        } catch (error) {
+            if (error.code === Logger.errors.CALL_EXCEPTION) { return null; }
+            return null;
+        }
     }
 
     async _getResolver(name: string): Promise<string> {
@@ -1523,7 +1537,12 @@ export class BaseProvider extends Provider implements EnsProvider {
             data: ("0x0178b8bf" + namehash(name).substring(2))
         };
 
-        return this.formatter.callAddress(await this.call(transaction));
+        try {
+            return this.formatter.callAddress(await this.call(transaction));
+        } catch (error) {
+            if (error.code === Logger.errors.CALL_EXCEPTION) { return null; }
+            throw error;
+        }
     }
 
     async resolveName(name: string | Promise<string>): Promise<string> {

diff --git a/packages/providers/src.ts/etherscan-provider.ts b/packages/providers/src.ts/etherscan-provider.ts
@@ -98,8 +98,18 @@ function checkError(method: string, error: any, transaction: any): any {
     // incompatibility; maybe for v6 consider forwarding reverts as errors
     if (method === "call" && error.code === Logger.errors.SERVER_ERROR) {
         const e = error.error;
-        if (e && e.message.match("reverted") && isHexString(e.data)) {
-            return e.data;
+
+        // Etherscan keeps changing their string
+        if (e && (e.message.match(/reverted/i) || e.message.match(/VM execution error/i))) {
+            // Etherscan prefixes the data like "Reverted 0x1234"
+            let data = e.data;
+            if (data) { data = "0x" + data.replace(/^.*0x/i, ""); }
+
+            if (isHexString(data)) { return data; }
+
+            logger.throwError("missing revert data in call exception", Logger.errors.CALL_EXCEPTION, {
+                error, data: "0x"
+            });
         }
     }
 

diff --git a/packages/providers/src.ts/json-rpc-provider.ts b/packages/providers/src.ts/json-rpc-provider.ts
@@ -30,6 +30,10 @@ function checkError(method: string, error: any, params: any): any {
         if (e && e.message.match("reverted") && isHexString(e.data)) {
             return e.data;
         }
+
+        logger.throwError("missing revert data in call exception", Logger.errors.CALL_EXCEPTION, {
+            error, data: "0x"
+        });
     }
 
     let message = error.message;