diff options
| -rw-r--r-- | default.nix | 10 | ||||
| -rw-r--r-- | nix/readTree/README.md | 9 | ||||
| -rw-r--r-- | nix/readTree/default.nix | 43 | ||||
| -rw-r--r-- | nix/readTree/tests/default.nix | 15 |
4 files changed, 53 insertions, 24 deletions
diff --git a/default.nix b/default.nix index 19c00bb2c4d2..bb9bc703bf2c 100644 --- a/default.nix +++ b/default.nix @@ -56,8 +56,10 @@ let }; }; - readTree' = import ./nix/readTree { - argsFilter = depotArgsFilter; + readDepot = depotArgs: import ./nix/readTree {} { + args = depotArgs; + path = ./.; + filter = depotArgsFilter; }; # To determine build targets, we walk through the depot tree and @@ -91,7 +93,7 @@ let (node.meta.targets or [])) else []; -in fix(self: (readTree' { +in fix(self: (readDepot { depot = self; # Pass third_party as 'pkgs' (for compatibility with external @@ -107,7 +109,7 @@ in fix(self: (readTree' { # Note that it is intended for exceptional circumstance, such as # debugging by bisecting nixpkgs. externalArgs = args; -} ./.) // { +}) // { # Make the path to the depot available for things that might need it # (e.g. NixOS module inclusions) path = ./.; diff --git a/nix/readTree/README.md b/nix/readTree/README.md index 138abbe30583..b56bc944caba 100644 --- a/nix/readTree/README.md +++ b/nix/readTree/README.md @@ -70,8 +70,13 @@ the tree as empty nodes (`{}`). ## Import structure -`readTree` is called with two parameters: The arguments to pass to all imports, -and the initial path at which to start the traversal. +`readTree` is called with an argument set containing a few parameters: + +* `path`: Initial path at which to start the traversal. +* `args`: Arguments to pass to all imports. +* `filter`: (optional) A function to filter the argument set on each + import based on the location in the tree. This can be used to, for + example, implement a "visibility" system inside of a tree. The package headers in this repository follow the form `{ pkgs, ... }:` where `pkgs` is a fixed-point of the entire package tree (see the `default.nix` at the diff --git a/nix/readTree/default.nix b/nix/readTree/default.nix index 633915f78b3d..b105738a4f80 100644 --- a/nix/readTree/default.nix +++ b/nix/readTree/default.nix @@ -5,11 +5,17 @@ # Provides a function to automatically read a a filesystem structure # into a Nix attribute set. # -# Optionally accepts an argument `argsFilter` on import, which is a -# function that receives the current tree location (as a list of -# strings) and the argument set and can arbitrarily modify it. -{ argsFilter ? (x: _parts: x) -, ... }: +# Called with an attribute set taking the following arguments: +# +# path: Path to a directory from which to start reading the tree. +# +# args: Argument set to pass to each imported file. +# +# filter: Function to filter `args` based on the tree location. This should +# be a function of the form `args -> location -> args`, where the +# location is a list of strings representing the path components of +# the current readTree target. Optional. +{ ... }: let inherit (builtins) @@ -53,7 +59,7 @@ let # The marker is added to every set that was imported directly by # readTree. - importWithMark = args: path: parts: + importWithMark = args: path: parts: filter: let importedFile = import path; pathType = builtins.typeOf importedFile; @@ -61,7 +67,7 @@ let assert assertMsg (pathType == "lambda") "readTree: trying to import ${toString path}, but it’s a ${pathType}, you need to make it a function like { depot, pkgs, ... }"; - importedFile (argsFilter (argsWithPath args parts) parts); + importedFile (filter (argsWithPath args parts) parts); in if (isAttrs imported) then imported // (marker parts) else imported; @@ -70,14 +76,14 @@ let let res = match "(.*)\\.nix" file; in if res == null then null else head res; - readTree = { args, initPath, rootDir, parts }: + readTree = { args, initPath, rootDir, parts, argsFilter }: let dir = readDirVisible initPath; joinChild = c: initPath + ("/" + c); self = if rootDir then { __readTree = []; } - else importWithMark args initPath parts; + else importWithMark args initPath parts argsFilter; # Import subdirectories of the current one, unless the special # `.skip-subtree` file exists which makes readTree ignore the @@ -90,6 +96,7 @@ let children = if hasAttr ".skip-subtree" dir then [] else map (c: { name = c; value = readTree { + inherit argsFilter; args = args; initPath = (joinChild c); rootDir = false; @@ -101,16 +108,22 @@ let nixFiles = filter (f: f != null) (map nixFileName (attrNames dir)); nixChildren = map (c: let p = joinChild (c + ".nix"); in { name = c; - value = importWithMark args p (parts ++ [ c ]); + value = importWithMark args p (parts ++ [ c ]) argsFilter; }) nixFiles; in if dir ? "default.nix" then (if isAttrs self then self // (listToAttrs children) else self) else (listToAttrs (nixChildren ++ children) // (marker parts)); in { - __functor = _: args: initPath: readTree { - inherit args initPath; - rootDir = true; - parts = []; - }; + __functor = _: + { path + , args + , filter ? (x: _parts: x) }: + readTree { + inherit args; + argsFilter = filter; + initPath = path; + rootDir = true; + parts = []; + }; } diff --git a/nix/readTree/tests/default.nix b/nix/readTree/tests/default.nix index f3cab2844785..06d4a12dd08f 100644 --- a/nix/readTree/tests/default.nix +++ b/nix/readTree/tests/default.nix @@ -8,7 +8,10 @@ let assertThrows ; - tree-ex = depot.nix.readTree {} ./test-example; + tree-ex = depot.nix.readTree { + path = ./test-example; + args = {}; + }; example = it "corresponds to the README example" [ (assertEq "third_party attrset" @@ -32,7 +35,10 @@ let "roquefort") ]; - tree-tl = depot.nix.readTree {} ./test-tree-traversal; + tree-tl = depot.nix.readTree { + path = ./test-tree-traversal; + args = {}; + }; traversal-logic = it "corresponds to the traversal logic in the README" [ (assertEq "skip subtree default.nix is read" @@ -82,7 +88,10 @@ let # these each call readTree themselves because the throws have to happen inside assertThrows wrong = it "cannot read these files and will complain" [ (assertThrows "this file is not a function" - (depot.nix.readTree {} ./test-wrong-not-a-function).not-a-function) + (depot.nix.readTree { + path = ./test-wrong-not-a-function; + args = {}; + }).not-a-function) # can’t test for that, assertThrows can’t catch this error # (assertThrows "this file is a function but doesn’t have dots" # (depot.nix.readTree {} ./test-wrong-no-dots).no-dots-in-function) |