Nested follows cause flake interactions to update the nested input #460

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opened 2024-08-04 20:50:18 +00:00 by diniamo · 2 comments

diniamo commented

2024-08-04 20:50:18 +00:00

Describe the bug

The title sums it up pretty well: let's say a flake contains inputs.a.inputs.b.inputs.c.follows = "...", doing any sort of interaction with the flake (for example nix --verbose flake show) causes it to update input b.

Steps To Reproduce

Paste this into a file named flake.nix

{
  inputs = {
    nixpkgs.url = "nixpkgs/nixos-unstable";

    nvf = {
      url = "github:NotAShelf/nvf";
      inputs.nixpkgs.follows = "nixpkgs";
      inputs.zig.inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = _: {};
}

Run nix --verbose flake show twice
Notice that it still tries to fetch the zig-overlay input on the second run, and if you were to manually lock the input to an older commit, it would update it.

Expected behavior

The random fetch and update don't happen.

`nix --version` output

nix (Lix, like Nix) 2.90.0

## Describe the bug The title sums it up pretty well: let's say a flake contains `inputs.a.inputs.b.inputs.c.follows = "..."`, doing any sort of interaction with the flake (for example `nix --verbose flake show`) causes it to update input `b`. ## Steps To Reproduce 1. Paste this into a file named `flake.nix` ```nix { inputs = { nixpkgs.url = "nixpkgs/nixos-unstable"; nvf = { url = "github:NotAShelf/nvf"; inputs.nixpkgs.follows = "nixpkgs"; inputs.zig.inputs.nixpkgs.follows = "nixpkgs"; }; }; outputs = _: {}; } ``` 2. Run `nix --verbose flake show` twice 3. Notice that it still tries to fetch the zig-overlay input on the second run, and if you were to manually lock the input to an older commit, it would update it. ## Expected behavior The random fetch and update don't happen. ## `nix --version` output `nix (Lix, like Nix) 2.90.0`

diniamo added the

bug

label 2024-08-04 20:50:18 +00:00

ma27 self-assigned this 2024-08-18 19:52:51 +00:00

jade commented

2024-08-18 21:48:52 +00:00

Owner

This bug's evil twin: #465

This bug's evil twin: https://git.lix.systems/lix-project/lix/issues/465

jade added the

Area/flakes

label 2024-08-18 21:48:56 +00:00

lix-bot commented

2024-08-19 16:38:04 +00:00

Member

This issue was mentioned on Gerrit on the following CLs:

commit message in cl/1802 ("flake: don't refetch unmodified inputs by recursive follows")

This issue was mentioned on Gerrit on the following CLs: * commit message in [cl/1802](https://gerrit.lix.systems/c/lix/+/1802) ("flake: don't refetch unmodified inputs by recursive follows")