From 4576c676752232a33a51ba565dbf8d4f8cdcf463 Mon Sep 17 00:00:00 2001
From: Silvan Mosberger <silvan.mosberger@tweag.io>
Date: Fri, 19 May 2023 17:25:30 +0200
Subject: [PATCH] Integrate sources with subpaths into mkDerivation

Make root, subpath internal

Adapted from https://github.com/NixOS/nixpkgs/pull/112083

Co-Authored-By: Robert Hensing <robert@roberthensing.nl>
---
 lib/fileset.nix                         |  8 ++++----
 pkgs/stdenv/generic/make-derivation.nix | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/lib/fileset.nix b/lib/fileset.nix
index d975068ebc911..40391960593f0 100644
--- a/lib/fileset.nix
+++ b/lib/fileset.nix
@@ -438,8 +438,8 @@ in {
       fileset :: FileSet,
     } -> {
       outPath :: String,
-      root :: String,
-      subpath :: String,
+      _root :: String,
+      _subpath :: String,
     }
   */
   importToStore = { name ? "source", base ? entryPoint, entryPoint, fileset }:
@@ -497,8 +497,8 @@ in {
       };
       components = removePrefix base entryPoint;
     in {
-      inherit root;
-      subpath = toSubpath components;
+      _root = root;
+      _subpath = toSubpath components;
       outPath =
         if components == [] then
           root
diff --git a/pkgs/stdenv/generic/make-derivation.nix b/pkgs/stdenv/generic/make-derivation.nix
index 40ad357739b70..52ddc9bc434d4 100644
--- a/pkgs/stdenv/generic/make-derivation.nix
+++ b/pkgs/stdenv/generic/make-derivation.nix
@@ -437,6 +437,20 @@ else let
       inherit doCheck doInstallCheck;
 
       inherit outputs;
+
+      ${if attrs ? src then "src" else null} =
+        if attrs.src ? _root && attrs.src ? _subpath then
+          attrs.src.root
+        else
+          attrs.src;
+
+      # TODO simplify by adding to unpackPhase instead.
+      #      This wasn't done yet to avoid a mass rebuild while working on this.
+      postUnpack = if attrs.src ? _root && attrs.src ? _subpath && attrs.src._subpath != "./." then ''
+        sourceRoot="$sourceRoot"/${lib.escapeShellArg attrs.src._subpath}
+        ${attrs.postUnpack or ""}
+      '' else attrs.postUnpack or null;
+
     } // lib.optionalAttrs (__contentAddressed) {
       inherit __contentAddressed;
       # Provide default values for outputHashMode and outputHashAlgo because