lib.version: init

lib/default.nix

@@ -25,6 +25,7 @@ lib.makeExtensible (
     options = call ./options.nix { };
     plugins = call ./plugins { };
     utils = call ./utils.nix { inherit _nixvimTests; } // call ./utils.internal.nix { };
+    version = call ./version.nix { inherit flake; };
 
     # Top-level helper aliases:
     # TODO: deprecate some aliases

lib/version.nix

@@ -0,0 +1,140 @@
+{
+  lib,
+  flake,
+}:
+let
+  inherit (builtins)
+    isList
+    mapAttrs
+    head
+    tail
+    ;
+
+  lockFile = lib.importJSON ../flake.lock;
+
+  /**
+    Resolve an input spec into a node name.
+
+    # Inputs
+
+    `inputSpec` ([String] | String)
+    : Either a node name, or a "follows" path relative to the root node.
+
+    # Output
+
+    The node name.
+
+    # Upstream
+
+    This is based on `resolveInput` in nix's [call-flake.nix]
+
+    [call-flake.nix]: https://github.com/NixOS/nix/blob/46beb9af/src/libflake/call-flake.nix#L21-L25
+  */
+  resolveInput =
+    inputSpec: if isList inputSpec then getInputByPath lockFile.root inputSpec else inputSpec;
+
+  /**
+    Follow an input attrpath from the root node, stepping through each node along the path.
+
+    # Inputs
+
+    `nodeName`
+    : The name of the _current_ node.
+
+    `path`
+    : The input attrpath to follow.
+      E.g. `["dwarffs" "nixpkgs"]`
+
+    # Outputs
+
+    The final node name.
+
+    # Upstream
+
+    This is based on `getInputByPath` in nix's [call-flake.nix]
+
+    [call-flake.nix]: https://github.com/NixOS/nix/blob/46beb9af/src/libflake/call-flake.nix#L27-L37
+  */
+  getInputByPath =
+    nodeName: path:
+    if path == [ ] then
+      nodeName
+    else
+      getInputByPath (resolveInput lockFile.nodes.${nodeName}.inputs.${head path}) (tail path);
+
+  # Inputs specified in our flake.lock
+  lockedInputs = lib.pipe lockFile.nodes.${lockFile.root}.inputs [
+    (mapAttrs (inputName: inputSpec: lockFile.nodes.${resolveInput inputSpec}))
+  ];
+
+  # Our actual inputs, potentially modified by end-user's "follows"
+  realInputs = flake.inputs;
+in
+{
+  /**
+    Check whether a specific input is modified when compared to our `flake.lock` file.
+
+    This can happen when a user specifies one of our inputs "follows" one of theirs.
+  */
+  isInputModified =
+    name:
+    assert lib.assertMsg (
+      realInputs ? ${name}
+    ) "isInputModified: `${lib.strings.escapeNixIdentifier name}` is not in `inputs`.";
+    assert lib.assertMsg (
+      lockedInputs ? ${name}
+    ) "isInputModified: `${lib.strings.escapeNixIdentifier name}` is not in `flake.lock`.";
+    let
+      # If a non-flake input is used, `sourceInfo` will be missing
+      real = realInputs.${name}.sourceInfo.narHash or null;
+      locked = lockedInputs.${name}.locked.narHash;
+    in
+    real != locked;
+
+  /**
+    Nixvim's current commit, or the specified default when nixvim's repo is dirty.
+  */
+  revisionWithDefault = default: flake.sourceInfo.rev or default;
+
+  /**
+    Nixvim's current commit, defaulting to the canonical branch name for this release.
+  */
+  revision = with lib.nixvim.version; revisionWithDefault releaseBranch;
+
+  /**
+    Nixvim's release.
+
+    Derived from the nixpkgs branch targeted in `flake.lock`.
+  */
+  release =
+    let
+      inherit (lockedInputs.nixpkgs.original) ref;
+      parts = lib.splitString "-" ref;
+    in
+    lib.last parts;
+
+  /**
+    The canonical branch name associated with this release of nixvim.
+  */
+  releaseBranch =
+    let
+      inherit (lib.nixvim.version) release;
+    in
+    if release == "unstable" then "main" else "nixos-" + release;
+
+  /**
+    Whether the nixpkgs input is correct for this release of nixvim.
+
+    Can be used to identify mismatched nixpkgs inputs, usually caused our input
+    following a user's input from another channel
+  */
+  correctNixpkgsChannel =
+    let
+      nixvimRelease = lib.nixvim.version.release;
+      nixpkgsRelease = lib.trivial.release;
+    in
+    if nixvimRelease == "unstable" then
+      true # TODO: how do we know what channel a nixpkgs instance is on?
+    else
+      nixvimRelease == nixpkgsRelease;
+}