buildGoModule: add goSum attribute to make goModules rebuild (#399532)

pkgs/build-support/go/module.nix

@@ -37,6 +37,9 @@ lib.extendMkDerivation {
           "buildGoModule: vendorHash is missing"
       ),
 
+      # The go.sum file to track which can cause rebuilds.
+      goSum ? null,
+
       # Whether to delete the vendor folder supplied with the source.
       deleteVendor ? false,
 
@@ -69,13 +72,24 @@ lib.extendMkDerivation {
         vendorHash
         deleteVendor
         proxyVendor
+        goSum
         ;
       goModules =
         if (finalAttrs.vendorHash == null) then
           ""
         else
           (stdenv.mkDerivation {
-            name = "${finalAttrs.name or "${finalAttrs.pname}-${finalAttrs.version}"}-go-modules";
+            name =
+              let
+                prefix = "${finalAttrs.name or "${finalAttrs.pname}-${finalAttrs.version}"}-";
+
+                # If "goSum" is supplied then it can cause "goModules" to rebuild.
+                # Attach the hash name of the "go.sum" file so we can rebuild when it changes.
+                suffix = lib.optionalString (
+                  finalAttrs.goSum != null
+                ) "-${(lib.removeSuffix "-go.sum" (lib.removePrefix "${builtins.storeDir}/" finalAttrs.goSum))}";
+              in
+              "${prefix}go-modules${suffix}";
 
             nativeBuildInputs = (finalAttrs.nativeBuildInputs or [ ]) ++ [
               go
@@ -83,7 +97,7 @@ lib.extendMkDerivation {
               cacert
             ];
 
-            inherit (finalAttrs) src modRoot;
+            inherit (finalAttrs) src modRoot goSum;
 
             # The following inheritance behavior is not trivial to expect, and some may
             # argue it's not ideal. Changing it may break vendor hashes in Nixpkgs and