Add inputs.self.lfs flake attribute

doc/manual/rl-next/git-lfs-support.md

@@ -1,11 +1,18 @@
 ---
 synopsis: "Git LFS support"
-prs: [10153]
+prs: [10153, 12468]
 ---
 
 The Git fetcher now supports Large File Storage (LFS). This can be enabled by passing the attribute `lfs = true` to the fetcher, e.g.
 ```console
 nix flake prefetch 'git+ssh://git@github.com/Apress/repo-with-large-file-storage.git?lfs=1'
 ```
 
+A flake can also declare that it requires lfs to be enabled:
+```
+{
+  inputs.self.lfs = true;
+}
+```
+
 Author: [**@b-camacho**](https://github.com/b-camacho), [**@kip93**](https://github.com/kip93)

src/libflake/flake/flake.cc

@@ -381,7 +381,7 @@ static FlakeRef applySelfAttrs(
 {
     auto newRef(ref);
 
-    std::set<std::string> allowedAttrs{"submodules"};
+    std::set<std::string> allowedAttrs{"submodules", "lfs"};
 
     for (auto & attr : flake.selfAttrs) {
         if (!allowedAttrs.contains(attr.first))

tests/nixos/fetch-git/test-cases/lfs/default.nix

@@ -193,5 +193,36 @@
 
       assert fetched_lfs == fetched_flake, \
         f"fetching as flake input (store path {fetched_flake}) yielded a different result than using fetchGit (store path {fetched_lfs})"
+
+
+    with subtest("Check self.lfs"):
+      client.succeed(f"""
+        printf '{{
+          inputs.self.lfs = true;
+          outputs = {{ self }}: {{ }};
+        }}' >{repo.path}/flake.nix
+      """)
+      client.succeed(f"{repo.git} add : >&2")
+      client.succeed(f"{repo.git} commit -m 'add flake' >&2")
+      client.succeed(f"{repo.git} push origin main >&2")
+
+      # memorize the revision
+      self_lfs_rev = client.succeed(f"{repo.git} rev-parse HEAD").strip()
+
+      with TemporaryDirectory() as tempdir:
+        client.succeed(f"mkdir -p {tempdir}")
+        client.succeed(f"""
+          printf '{{
+            inputs.foo = {{
+              url = "git+{repo.remote}?ref=main&rev={self_lfs_rev}";
+            }};
+            outputs = {{ foo, self }}: {{ inherit (foo) outPath; }};
+          }}' >{tempdir}/flake.nix
+        """)
+        fetched_self_lfs = client.succeed(f"""
+          nix eval --debug --raw {tempdir}#.outPath
+        """)
+
+    client.succeed(f"cmp {repo.path}/beeg {fetched_self_lfs}/beeg >&2")
   '';
 }