lib/customization: Improve callPackage error message for missing args

This uses the levenshtein distance to look through all possible
arguments to find ones that are close to what was requested:

  error: Function in /home/infinisil/src/nixpkgs/pkgs/tools/text/ripgrep/default.nix
    called without required argument "fetchFromGithub",
    did you mean "fetchFromGitHub" or "fetchFromGitLab"?

With https://github.com/NixOS/nix/pull/3468 (in current nixUnstable) the error
message becomes even better, adding line location info
This commit is contained in:
Silvan Mosberger 2020-07-25 19:54:37 +02:00 committed by Profpatsch
parent f8c1aee5da
commit 1c00bf3948

View File

@ -117,8 +117,55 @@ rec {
callPackageWith = autoArgs: fn: args:
let
f = if lib.isFunction fn then fn else import fn;
auto = builtins.intersectAttrs (lib.functionArgs f) autoArgs;
in makeOverridable f (auto // args);
fargs = lib.functionArgs f;
# All arguments that will be passed to the function
# This includes automatic ones and ones passed explicitly
allArgs = builtins.intersectAttrs fargs autoArgs // args;
# A list of argument names that the function requires, but
# wouldn't be passed to it
missingArgs = lib.attrNames
# Filter out arguments that have a default value
(lib.filterAttrs (name: value: ! value)
# Filter out arguments that would be passed
(removeAttrs fargs (lib.attrNames allArgs)));
# Get a list of suggested argument names for a given missing one
getSuggestions = arg: lib.pipe (autoArgs // args) [
lib.attrNames
# Only use ones that are at most 2 edits away. While mork would work,
# levenshteinAtMost is only fast for 2 or less.
(lib.filter (lib.strings.levenshteinAtMost 2 arg))
# Put strings with shorter distance first
(lib.sort (x: y: lib.strings.levenshtein x arg < lib.strings.levenshtein y arg))
# Only take the first couple results
(lib.take 3)
# Quote all entries
(map (x: "\"" + x + "\""))
];
prettySuggestions = suggestions:
if suggestions == [] then ""
else if lib.length suggestions == 1 then ", did you mean ${lib.elemAt suggestions 0}?"
else ", did you mean ${lib.concatStringsSep ", " (lib.init suggestions)} or ${lib.last suggestions}?";
errorForArg = arg:
let
loc = builtins.unsafeGetAttrPos arg fargs;
# loc' can be removed once lib/minver.nix is >2.3.4, since that includes
# https://github.com/NixOS/nix/pull/3468 which makes loc be non-null
loc' = if loc != null then loc.file + ":" + toString loc.line
else if ! lib.isFunction fn then
toString fn + lib.optionalString (lib.sources.pathIsDirectory fn) "/default.nix"
else "<unknown location>";
in "Function called without required argument \"${arg}\" at "
+ "${loc'}${prettySuggestions (getSuggestions arg)}";
# Only show the error for the first missing argument
error = errorForArg (lib.head missingArgs);
in if missingArgs == [] then makeOverridable f allArgs else throw error;
/* Like callPackage, but for a function that returns an attribute