Remove invalid networks check from Sourcify fetcher

packages/fetch-and-compile/README.md

@@ -124,7 +124,7 @@ export interface FetchAndCompileOptions {
 
 ### `getSupportedNetworks`
 
-If you want a list of supported networks, you can call `getSupportedNetworks`:
+If you want a (potentially partial) list of supported networks, you can call `getSupportedNetworks`:
 
 ```ts
 import { getSupportedNetworks } from "@truffle/fetch-and-compile";
@@ -140,6 +140,8 @@ const networks = getSupportedNetworks();
 // }
 ```
 
+Note that there may be additional unlisted supported networks.
+
 You can also pass in a list of fetchers if you want to restrict the output to the networks
 supported by the fetchers you list. (You can also pass in a config and it will use the `sourceFetchers`
 property if set, or a `FetchAndCompileOptions` and it will use the `fetch.precedence` field if set.)

packages/source-fetcher/lib/sourcify.ts

@@ -3,7 +3,7 @@ const debug = debugModule("source-fetcher:sourcify");
 
 import type { Fetcher, FetcherConstructor } from "./types";
 import type * as Types from "./types";
-import { removeLibraries, InvalidNetworkError } from "./common";
+import { removeLibraries } from "./common";
 import { networkNamesById, networksByName } from "./networks";
 import retry from "async-retry";
 
@@ -164,12 +164,8 @@ const SourcifyFetcher: FetcherConstructor = class SourcifyFetcher
   constructor(networkId: number) {
     this.networkId = networkId;
     this.networkName = networkNamesById[networkId];
-    if (
-      this.networkName === undefined ||
-      !SourcifyFetcher.supportedNetworks.has(this.networkName)
-    ) {
-      throw new InvalidNetworkError(networkId, "sourcify");
-    }
+    //we no longer check if the network is supported; the list is now only
+    //used for if you explicitly ask
   }
 
   static getSupportedNetworks(): Types.SupportedNetworks {