stash: Refactor to use finalAttrs, straighten out src references

Previously, it was somewhat difficult to override the source tree for
stash: The `src` attribute was used in several places, some of which 
were unreachable. Now, using the `finalAttrs` argument, both the go
and yarn builds can use the same source tree, overriding it only once.

This change also adds a `postPatch` attribute, whose sole purpose is 
to copy the yarn build result into place, which again makes it easier
to override the source tree without having to duplicate the 
load-bearing other items on `preBuild`.

pkgs/by-name/st/stash/package.nix

@@ -21,22 +21,18 @@ let
     ;
 
   pname = "stash";
-
-  src = fetchFromGitHub {
-    owner = "stashapp";
-    repo = "stash";
-    tag = "v${version}";
-    hash = srcHash;
-  };
-
+in
+buildGoModule (
+  finalAttrs:
+  let
     frontend = stdenv.mkDerivation (final: {
-    inherit version;
-    pname = "${pname}-ui";
-    src = "${src}/ui/v2.5";
+      pname = "${finalAttrs.pname}-ui";
+      inherit (finalAttrs) version gitHash;
+      src = "${finalAttrs.src}/ui/v2.5";
 
       yarnOfflineCache = fetchYarnDeps {
         yarnLock = "${final.src}/yarn.lock";
-      hash = yarnHash;
+        hash = finalAttrs.yarnHash;
       };
 
       nativeBuildInputs = [
@@ -48,7 +44,7 @@ let
 
       postPatch = ''
         substituteInPlace codegen.ts \
-        --replace-fail "../../graphql/" "${src}/graphql/"
+          --replace-fail "../../graphql/" "${finalAttrs.src}/graphql/"
       '';
 
       buildPhase = ''
@@ -56,8 +52,8 @@ let
 
         export HOME=$(mktemp -d)
         export VITE_APP_DATE='1970-01-01 00:00:00'
-      export VITE_APP_GITHASH=${gitHash}
-      export VITE_APP_STASH_VERSION=v${version}
+        export VITE_APP_GITHASH=${finalAttrs.gitHash}
+        export VITE_APP_STASH_VERSION=v${finalAttrs.version}
         export VITE_APP_NOLEGACY=true
 
         yarn --offline run gqlgen
@@ -71,21 +67,29 @@ let
       dontInstall = true;
       dontFixup = true;
     });
-in
-buildGoModule {
+  in
+  {
     inherit
       pname
-    src
       version
+      gitHash
+      yarnHash
       vendorHash
       ;
 
+    src = fetchFromGitHub {
+      owner = "stashapp";
+      repo = "stash";
+      tag = "v${finalAttrs.version}";
+      hash = srcHash;
+    };
+
     ldflags = [
       "-s"
       "-w"
       "-X 'github.com/stashapp/stash/internal/build.buildstamp=1970-01-01 00:00:00'"
-    "-X 'github.com/stashapp/stash/internal/build.githash=${gitHash}'"
-    "-X 'github.com/stashapp/stash/internal/build.version=v${version}'"
+      "-X 'github.com/stashapp/stash/internal/build.githash=${finalAttrs.gitHash}'"
+      "-X 'github.com/stashapp/stash/internal/build.version=v${finalAttrs.version}'"
       "-X 'github.com/stashapp/stash/internal/build.officialBuild=false'"
     ];
     tags = [
@@ -95,8 +99,11 @@ buildGoModule {
 
     subPackages = [ "cmd/stash" ];
 
-  preBuild = ''
+    postPatch = ''
       cp -a ${frontend} ui/v2.5/build
+    '';
+
+    preBuild = ''
       # `go mod tidy` requires internet access and does nothing
       echo "skip_mod_tidy: true" >> gqlgen.yml
       # remove `-trimpath` fron `GOFLAGS` because `gqlgen` does not work with it
@@ -112,7 +119,7 @@ buildGoModule {
         inherit (nixosTests) stash;
         version = testers.testVersion {
           package = stash;
-        version = "v${version} (${gitHash}) - Unofficial Build - 1970-01-01 00:00:00";
+          version = "v${finalAttrs.version} (${finalAttrs.gitHash}) - Unofficial Build - 1970-01-01 00:00:00";
         };
       };
     };
@@ -122,7 +129,7 @@ buildGoModule {
       description = "Organizer for your adult videos/images";
       license = lib.licenses.agpl3Only;
       homepage = "https://stashapp.cc/";
-    changelog = "https://github.com/stashapp/stash/blob/v${version}/ui/v2.5/src/docs/en/Changelog/v${lib.versions.major version}${lib.versions.minor version}0.md";
+      changelog = "https://github.com/stashapp/stash/blob/v${finalAttrs.version}/ui/v2.5/src/docs/en/Changelog/v${lib.versions.major finalAttrs.version}${lib.versions.minor finalAttrs.version}0.md";
       maintainers = with lib.maintainers; [
         Golo300
         DrakeTDL
@@ -134,4 +141,5 @@ buildGoModule {
         "aarch64-darwin"
       ];
     };
-}
+  }
+)