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https://github.com/dramforever/nix-dram

Nix Flakes with a modified frontend, by dramforever
https://github.com/dramforever/nix-dram
nix-flake
Last synced: about 12 hours ago
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Nix Flakes with a modified frontend, by dramforever
Host: GitHub
URL: https://github.com/dramforever/nix-dram
Owner: dramforever
Created: 2021-02-01T10:08:11.000Z (almost 4 years ago)
Default Branch: main
Last Pushed: 2024-12-16T08:29:00.000Z (24 days ago)
Last Synced: 2025-01-01T11:07:49.380Z (8 days ago)
Topics: nix-flake
Language: Haskell
Homepage:
Size: 102 KB
Stars: 79
Watchers: 7
Forks: 5
Open Issues: 3
Metadata Files:
- Readme: README.md
Awesome Lists containing this project

README

        # `nix-dram`

![Build status](https://github.com/dramforever/nix-dram/actions/workflows/check.yml/badge.svg)

*Nix with a modified frontend, by dramforever*

## Nix Flake

This repository contains a Nix Flake. To use it, use the following Flake URL:

```plain

github:dramforever/nix-dram

```

The modified Nix is available as `defaultApp`:

```console

$ nix run github:dramforever/nix-dram -- --version

nix (Nix) 2.4pre20201205_a5d85d0

```

The binary cache of this flake is available on Cachix. Set it up with:

```console

$ cachix use dram

```

Check out [a list of the contents of this flake](#contents-of-this-flake).

---

## What is this about?

The main reason of this fork is as follows

As a [Nix Flakes][nix-flakes] user, I was constantly typing `nixpkgs` over and

over again in commands like:

[nix-flakes]: https://nixos.org/manual/nix/unstable/command-ref/new-cli/nix3-flake.html

```console

$ nix run nixpkgs#hello

$ nix search nixpkgs hello

```

See the issue? The Flakes version of Nix does not have an idea of a 'default'

flake of any sort. At all. The best you can do is rename `nixpkgs` to `n`, but

still it frankly sucks.

Introducing `nix-dram`:

```console

$ nix run hello

$ nix search hello

```

Now there's no `nixpkgs` in sight. (You do need to add a `default-flake` option

to your Nix config though.)

Well that's the first thing anyway. It turns out that there were several things

I really want to change about Nix, so what I did is just to dump them here. A

detailed explanation follows.

## What's new?

There are three patches over Nix in this repository:

- `nix-flake-default.patch`: This changes the Nix CLI so that it parses

  `INSTALLABLE` arguments differently. The usage of the command `nix search` was

  also changed. See below for details.

- `nix-search-meta.patch`: This is not a very user-visible change. It basically

  alters `nix search` so that the `--json` option now dumps the entire `meta`

  attribute of the package.

  This is mainly used to support `nix-search-pretty` so that it has more

  information to work with, but could support other tooling as well.

There is a patch that was removed:

- `nix-flake-http-redirect.patch`: This arose from a thought on how we could

  keep using the good old channels in Nix Flakes. A quick thought is to just

  make Nix follow the redirect and save the final redirect target in

  `flake.lock`. This is an implementation of that idea.

  This was removed because it was already merged into Nix as pull request

  [#4595](https://github.com/NixOS/nix/pull/4595). See details below.

These changes are *incompatible* but is predicted to minimally affect current

usage. See below for details.

The documentation has *not* yet been changed to reflect the changes.

### Changes to `INSTALLABLE`

An configuration option `default-flake` is added, which specifies the default

flake URL when using the command line interface.

An `INSTALLABLE` command line argument, such as that of `nix run`, now has and

additional rule when parsing:

- If an `INSTALLABLE` looks like an attribute path, e.g. `foo.bar`, it is looked

  up as if it were `#foo.bar`, where `` is taken

  from the config. If the config is unset an error is reported.

  'Looks like an attribute path' is defined as fully matching the regular

  expression `[a-zA-Z0-9_"-][a-zA-Z0-9_".-]`

- Otherwise it is treated as a Flake `INSTALLABLE` as before.

Command line completion of the new `INSTALLABLE` syntax *is* supported.

[docs-indirect]: https://nixos.org/manual/nix/unstable/command-ref/new-cli/nix3-flake.html#types

(In cases where a Flake URL is expected (such as the arguments of

`--override-flake`), the behavior is not changed, i.e. using `nixpkgs` there

still means `--override-flake flake:nixpkgs [...]` .)

The following table shows the incompatibilities. The 'Legacy compatibility'

columns shows a syntax to use that both `nix-dram` and `nixFlakes` will

interpret according to the column 'Meaning in `nixFlakes`'. As mentioned above,

`` means the value taken from Nix configuration.

| Syntax | Meaning in `nix-dram` | Meaning in `nixFlakes` | Legacy compatibility |

|---|---|---|---|

| `blender` | `#blender` | `flake:blender` | `blender#` |

| `xorg.xclock` | `#xorg.xclock` | `./xorg.xclock/` (directory) | `./xorg.xclock` or `xorg.xclock/` |

One notable example is that if you want to refer to the `result` symlink from a

build output, you will need to specify `./result` or `result/`.

Here are examples of `INSTALLABLE` syntax that is unaffected:

| Syntax | Meaning |

|---|---|

| `.` | Current directory |

| `flake:blender` | Flake registry reference to `blender` |

| `./nix-dram` | The directory `nix-dram` within the current directory |

| `github:dramforever/nix-dram` | The GitHub repository [dramforever/nix-dram][dramforever-nix-dram] |

| `nixpkgs#hello` | `flake:nixpkgs#hello` |

[dramforever-nix-dram]: https://github.com/dramforever/nix-dram

As one can see the change affects a relative small number of use cases, and

incompatibilities can be worked around by appending one single character, which

even improves readability (though arguably so).

### Changes to `nix search`

The `nix search` command used to have this syntax:

```console

$ nix search [options] INSTALLABLE [KEYWORD]

```

It now has this syntax:

```console

$ nix search [options] [KEYWORD]

```

With the `INSTALLABLE` argument moved into an option, defaulting to that

specified in the `default-flake` option:

```plain

  -i, --installable INSTALLABLE     Search within this installable

```

The following table shows a comparison of use cases, the first of which is

predicted to be the most common.

| `nix-dram` | `nixFlakes` |

|---|---|

| `nix search hello` | `nix search default hello` |

| `nix search -i github:NixOS/nixpkgs hello` | `nix search github:NixOS/nixpkgs hello` |

| `nix search --expr foo hello` | `nix search --expr foo '' hello` |

| `nix search --file foo hello` | `nix search --file foo '' hello` |

### `nix-search` and `nix-search-pretty`

The `nix search` command, when given the `--json` option, now dumps the `meta`

attribute of each search result into a JSON property called `meta`.

```jsonc

{

  "legacyPackages.x86_64-linux.hello": {

    "pname": "hello",

    "version": "2.10",

    "description": "A program that produces a familiar, friendly greeting",

    "meta": {

      "available": true,

      "broken": false,

      "changelog": "https://git.savannah.gnu.org/cgit/hello.git/plain/NEWS?h=v2.10",

      "description": "A program that produces a familiar, friendly greeting",

      // ...

    }

  },

  // ...

}

```

`nix-search-pretty` is an example program that takes in this JSON and produces

colorized search output. `nix-search` is thin wrapper around the two. (Recorded

using [termtosvg]):

[termtosvg]: https://github.com/nbedos/termtosvg

![Demonstration of `nix-search-pretty`](images/nix-search-demo.svg)

`nix-search` is a wrapper around `nix-search-pretty` with similar usage to `nix

search`.

### Locked HTTP redirects in Flake inputs

(**Update**: This is already merged into Nix, as PR

[#4595](https://github.com/NixOS/nix/pull/4595))

(An issue was discovered with this approach, namely

[#4672](https://github.com/NixOS/nix/issues/4672), so this might end up getting

reverted. Either case, this patch no longer belongs in nix-dram.)

(Refer to [a post on Discourse][http-redir] for discussion.)

[http-redir]: https://discourse.nixos.org/t/future-of-channels-and-channels-nixos-org-in-a-flakes-world/11563

How could we refer to good old channels in a Flake URL? Here's a possible way

that I thought of:

1. When a user specifies an `http`/`https` URL, and it leads to (possibly

   several) redirects, we instead record the *final redirection destination* in

   `flake.lock`.

2. When a `flake.lock` is consulted to download the tarball, the URL in

   `flake.lock` is used.

This way specifying:

```nix

inputs.nixpkgs.url = "https://nixos.org/channels/nixos-unstable/nixexprs.tar.xz";

```

Would actually just work, as instead of failing with an invalid hash whenever

`nixos-unstable` updates, it saves the redirected URL which points to a stable

version. `flake.nix` would look something like this:

```jsonc

{

  "nodes": {

    "nixpkgs": {

      "locked": {

        "narHash": "sha256-N1qI50AkeTSBp1ffUCHrcK2re52wrn6euFFGGvFa2iw=",

        "type": "tarball",

        "url": "https://releases.nixos.org/nixos/unstable/nixos-21.05pre269929.ff96a0fa563/nixexprs.tar.xz"

      },

      "original": {

        "type": "tarball",

        "url": "https://nixos.org/channels/nixos-unstable/nixexprs.tar.xz"

      }

    },

    // ...

}

```

This way, older versions of Nix seeing this new lock file would just behave as

if someone used `--override-input`, and newer versions of Nix seeing the old

lock file with the pre-redirection URL would simply migrate it over when `nix

flake update --update-input` is used.

A major concern would be whether this redirection is actually part of the

intended interface of channels.nixos.org.

## More on the design

In the usual version of `nixFlakes`, it is in fact a conscious design choice

that you have to type `nixpkgs` every time. I tried making [a feature

request][the-feature-request] but got immmediately shut down, with an

explanation that `flake:nixpkgs` should not be prioritized as a 'default'. I

guess `flake:default` it is? In any case, it seems that the main author is open

to improvements, but is not *that* keen on the idea.

[the-feature-request]: https://github.com/NixOS/nix/issues/4438

After some discussion with [gytis-ivaskevicius], the default flake was made

configurable with the config file.

[gytis-ivaskevicius]: https://github.com/gytis-ivaskevicius

The basic idea of `nix-dram` is based on a slightly different prediction of how

Flakes will be used. Namely, it is predicted that users will create their own

personal Flake, referencing other Flakes as inputs. It will possibly provide a

package set for use in `nix` commands, various `nixosConfigurations`, and so on.

'Smaller' Flakes will exists and possibly even in great numbers, but each user

will have their own 'favorite' Flake to be used for most purposes. In `nix-dram`

that flake will be assigned `default-flake`. This indeed seems to be the use

case with popular demonstration repositories such as [nixflk] showing this

approach. Will this be how we use Flakes in the future? We will have to wait and

see.

[nixflk]: https://github.com/nrdxp/nixflk

This project is called `nix-dram` with the specific intention that it will

*never* be official. This is just one person, me, trying out one point in the

design space. That's how free software works, isn't it?

## Why is this not a script or a few shell functions?

(Reference: )

### `INSTALLABLE`

`nix-dram` handles everything where an `INSTALLABLE` is expected, so other

commands will also work, like `nix run`, `nix eval`, `nix develop`, `nix edit`.

(Yes I do use these all the time.) Even more obscure ones like and `nix copy`,

`nix bundle` also work.

A wrapper around `nix` would mean more subcommands I'd feel comfortable

implementing, honestly. On the other hand, if you do the C++ work, to modify

`INSTALLABLE` handling, there's just one function you absolutely need to touch,

namely `SourceExprCommand::parseInstallables`:

Another thing is compatibility with the old syntax. In the case of a wrapper, it

could be possible to be allow for both 'implicit flake' and 'explicit flake'

`INSTALLABLE` to work together as described in ['Changes to

`INSTALLABLE`'](#changes-to-installable), but it is going to be much more

handling.

A script would need to look at *each* `INSTALLABLE` argument and translate those

that need translating. Figuring out which arguments are `INSTALLABLE` is

actually the hardest part. A wrapper would need to either understand all the

options or require something like a `--` marker, otherwise it could accidentally

change `--override-flake foo bar` into `--override-flake #foo

#bar`.

### Command line completion

`nix-dram` also handles command line completion, so if you type `nix search

wires` and press tab, you get `wireshark`. Not having to type `nixpkgs#wires`

makes it much smoother. Conceivably you can write your completion handlers as

well, but that's honestly way too much for me.

That's because `nix` the program itself handles command line completion. If you

write a wrapper, you need to to translate completion requests/responses (Yes,

responses as well if you don't want `wires` completing to

`#wireshark`). You may even need to call `nix` *twice* to

generate completion for both the registry and attributes. It seems *much* more

work than just patching whatever generates the completion. And the problem of

handling options also occurs here.

### Are you sure this is the best way?

I like how much I get from the moderate amount of patching I did. The

main drawback I find is that I need to spend quite a bit of time building

`nix-dram`. I honestly think it's worth it.

### But what if...

If you think `nix-dram` is too much, you can write your own little scripts.

`nix-dram` might just not be what you need.

If you like specifying the flake all the time, then by all means just use the

usual Nix Flakes CLI.

If you have any idea on how what `nix-dram` does could be done in a more

lightweight way, I'm happy to take suggestions.

---

## Contents of this flake

```console

$ nix flake show github:dramforever/nix-dram

github:dramforever/nix-dram/[...]

├───apps

│   ├───aarch64-linux

│   │   ├───nix-dram: app

│   │   └───nix-dram-progress: app

│   ├───i686-linux

│   │   ├───nix-dram: app

│   │   └───nix-dram-progress: app

│   ├───x86_64-darwin

│   │   ├───nix-dram: app

│   │   └───nix-dram-progress: app

│   └───x86_64-linux

│       ├───nix-dram: app

│       └───nix-dram-progress: app

├───checks

│   ├───aarch64-linux

│   │   ├───nix-dram: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│   │   ├───nix-dram-progress: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│   │   ├───nix-nar-listing: derivation 'nix-nar-listing-0.1.0.0'

│   │   ├───nix-search: derivation 'nix-search'

│   │   └───nix-search-pretty: derivation 'nix-search-pretty-0.1.0.0'

│   ├───i686-linux

│   │   ├───nix-dram: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│   │   ├───nix-dram-progress: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│   │   ├───nix-nar-listing: derivation 'nix-nar-listing-0.1.0.0'

│   │   ├───nix-search: derivation 'nix-search'

│   │   └───nix-search-pretty: derivation 'nix-search-pretty-0.1.0.0'

│   ├───x86_64-darwin

│   │   ├───nix-dram: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│   │   ├───nix-dram-progress: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│   │   ├───nix-nar-listing: derivation 'nix-nar-listing-0.1.0.0'

│   │   ├───nix-search: derivation 'nix-search'

│   │   └───nix-search-pretty: derivation 'nix-search-pretty-0.1.0.0'

│   └───x86_64-linux

│       ├───nix-dram: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│       ├───nix-dram-progress: derivation 'nix-dram-2.4pre20201205_a5d85d0'

│       ├───nix-nar-listing: derivation 'nix-nar-listing-0.1.0.0'

│       ├───nix-search: derivation 'nix-search'

│       └───nix-search-pretty: derivation 'nix-search-pretty-0.1.0.0'

├───defaultApp

│   ├───aarch64-linux: app

│   ├───i686-linux: app

│   ├───x86_64-darwin: app

│   └───x86_64-linux: app

├───defaultPackage

│   ├───aarch64-linux: package 'nix-dram-2.4pre20201205_a5d85d0'

│   ├───i686-linux: package 'nix-dram-2.4pre20201205_a5d85d0'

│   ├───x86_64-darwin: package 'nix-dram-2.4pre20201205_a5d85d0'

│   └───x86_64-linux: package 'nix-dram-2.4pre20201205_a5d85d0'

├───overlay: Nixpkgs overlay

└───packages

    ├───aarch64-linux

    │   ├───nix-dram: package 'nix-dram-2.4pre20201205_a5d85d0'

    │   ├───nix-dram-progress: package 'nix-dram-2.4pre20201205_a5d85d0'

    │   ├───nix-nar-listing: package 'nix-nar-listing-0.1.0.0'

    │   ├───nix-search: package 'nix-search'

    │   └───nix-search-pretty: package 'nix-search-pretty-0.1.0.0'

    ├───i686-linux

    │   ├───nix-dram: package 'nix-dram-2.4pre20201205_a5d85d0'

    │   ├───nix-dram-progress: package 'nix-dram-2.4pre20201205_a5d85d0'

    │   ├───nix-nar-listing: package 'nix-nar-listing-0.1.0.0'

    │   ├───nix-search: package 'nix-search'

    │   └───nix-search-pretty: package 'nix-search-pretty-0.1.0.0'

    ├───x86_64-darwin

    │   ├───nix-dram: package 'nix-dram-2.4pre20201205_a5d85d0'

    │   ├───nix-dram-progress: package 'nix-dram-2.4pre20201205_a5d85d0'

    │   ├───nix-nar-listing: package 'nix-nar-listing-0.1.0.0'

    │   ├───nix-search: package 'nix-search'

    │   └───nix-search-pretty: package 'nix-search-pretty-0.1.0.0'

    └───x86_64-linux

        ├───nix-dram: package 'nix-dram-2.4pre20201205_a5d85d0'

        ├───nix-dram-progress: package 'nix-dram-2.4pre20201205_a5d85d0'

        ├───nix-nar-listing: package 'nix-nar-listing-0.1.0.0'

        ├───nix-search: package 'nix-search'

        └───nix-search-pretty: package 'nix-search-pretty-0.1.0.0'

```