fetchFromGitHub: re-fetch upon version changes

nixos/doc/manual/release-notes/rl-2405.section.md

@@ -165,6 +165,10 @@ The pre-existing [services.ankisyncd](#opt-services.ankisyncd.enable) has been m
   "mysecret"` becomes `services.aria2.rpcSecretFile = "/path/to/secret_file"`
   where the file `secret_file` contains the string `mysecret`.
 
+- `fetchFromGitHub`'s default `name` is now dependent to `rev`. This ensures that the result FOD is always re-fetced for each new version, and makes irrelevent hashes more discoverable.
+
+  This also means that the default `name` is no longer `"source"`. Packages must adhere to the [Nixpkgs specification about `sourceRoot`](https://nixos.org/manual/nixpkgs/unstable/#var-stdenv-sourceRoot) and specify `sourceRoot = "${src.name}/subdir"` instead of `sourceRoot = "source/subdir"`, or the build will fail.
+
 - Invidious has changed its default database username from `kemal` to `invidious`. Setups involving an externally provisioned database (i.e. `services.invidious.database.createLocally == false`) should adjust their configuration accordingly. The old `kemal` user will not be removed automatically even when the database is provisioned automatically.(https://github.com/NixOS/nixpkgs/pull/265857)
 
 - `inetutils` now has a lower priority to avoid shadowing the commonly used `util-linux`. If one wishes to restore the default priority, simply use `lib.setPrio 5 inetutils` or override with `meta.priority = 5`.

pkgs/build-support/fetchgit/default.nix

@@ -27,6 +27,7 @@ lib.makeOverridable (
 , # Impure env vars (https://nixos.org/nix/manual/#sec-advanced-attributes)
   # needed for netrcPhase
   netrcImpureEnvVars ? []
+, passthru ? {}
 , meta ? {}
 , allowedRequisites ? null
 }:
@@ -103,7 +104,7 @@ stdenvNoCC.mkDerivation {
 
   inherit preferLocalBuild meta allowedRequisites;
 
-  passthru = {
+  passthru = passthru // {
     gitRepoUrl = url;
   };
 }

pkgs/build-support/fetchgithub/default.nix

@@ -1,22 +1,30 @@
 { lib, fetchgit, fetchzip }:
 
 lib.makeOverridable (
-{ owner, repo, rev, name ? "source"
+{ owner, repo, rev
+, name ? null # Override with nullbto use the default value
+, pname ? "source-${owner}-${repo}"
 , fetchSubmodules ? false, leaveDotGit ? null
 , deepClone ? false, private ? false, forceFetchGit ? false
 , sparseCheckout ? []
 , githubBase ? "github.com", varPrefix ? null
+, passthru ? { }
 , meta ? { }
 , ... # For hash agility
 }@args:
 
 let
+  name = if args.name or null != null then args.name
+  else "${pname}-${rev}";
 
   position = (if args.meta.description or null != null
     then builtins.unsafeGetAttrPos "description" args.meta
     else builtins.unsafeGetAttrPos "rev" args
   );
   baseUrl = "https://${githubBase}/${owner}/${repo}";
+  newPassthru = passthru // {
+    inherit rev owner repo;
+  };
   newMeta = meta // {
     homepage = meta.homepage or baseUrl;
   } // lib.optionalAttrs (position != null) {
@@ -53,16 +61,19 @@ let
   fetcherArgs = (if useFetchGit
     then {
       inherit rev deepClone fetchSubmodules sparseCheckout; url = gitRepoUrl;
+      passthru = newPassthru;
     } // lib.optionalAttrs (leaveDotGit != null) { inherit leaveDotGit; }
     else {
       url = "${baseUrl}/archive/${rev}.tar.gz";
 
-      passthru = {
+      passthru = newPassthru // {
         inherit gitRepoUrl;
       };
     }
   ) // privateAttrs // passthruAttrs // { inherit name; };
 in
 
-fetcher fetcherArgs // { meta = newMeta; inherit rev owner repo; }
+(fetcher fetcherArgs).overrideAttrs (finalAttrs: previousAttrs: {
+  meta = newMeta;
+})
 )