lib: move assertMsg and assertOneOf to their own library file

Since the `assertOneOf` uses `lib.generators`, they are not really trivial
anymore and should go into their own library file.
This commit is contained in:
Profpatsch 2018-08-08 19:26:52 +02:00
parent 3e45b61a99
commit efdf618330
5 changed files with 53 additions and 46 deletions

44
lib/asserts.nix Normal file
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@ -0,0 +1,44 @@
{ lib }:
rec {
/* Print a trace message if pred is false.
Intended to be used to augment asserts with helpful error messages.
Example:
assertMsg false "nope"
=> false
stderr> trace: nope
assert (assertMsg ("foo" == "bar") "foo is not bar, silly"); ""
stderr> trace: foo is not bar, silly
stderr> assert failed at
Type:
assertMsg :: Bool -> String -> Bool
*/
# TODO(Profpatsch): add tests that check stderr
assertMsg = pred: msg:
if pred
then true
else builtins.trace msg false;
/* Specialized `assertMsg` for checking if val is one of the elements
of a list. Useful for checking enums.
Example:
let sslLibrary = "libressl"
in assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ]
=> false
stderr> trace: sslLibrary must be one of "openssl", "bearssl", but is: "libressl"
Type:
assertOneOf :: String -> ComparableVal -> List ComparableVal -> Bool
*/
assertOneOf = name: val: xs: assertMsg
(lib.elem val xs)
"${name} must be one of ${
lib.generators.toPretty {} xs}, but is: ${
lib.generators.toPretty {} val}";
}

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@ -38,10 +38,11 @@ let
systems = callLibs ./systems;
# misc
asserts = callLibs ./asserts.nix;
debug = callLibs ./debug.nix;
generators = callLibs ./generators.nix;
misc = callLibs ./deprecated.nix;
# domain-specific
fetchers = callLibs ./fetchers.nix;
@ -59,9 +60,7 @@ let
inherit (trivial) id const concat or and bitAnd bitOr bitXor bitNot
boolToString mergeAttrs flip mapNullable inNixShell min max
importJSON warn info nixpkgsVersion version mod compare
splitByAndCompare functionArgs setFunctionArgs isFunction
assertMsg assertOneOf;
splitByAndCompare functionArgs setFunctionArgs isFunction;
inherit (fixedPoints) fix fix' extends composeExtensions
makeExtensible makeExtensibleWithCustomName;
inherit (attrsets) attrByPath hasAttrByPath setAttrByPath
@ -118,6 +117,8 @@ let
unknownModule mkOption;
inherit (types) isType setType defaultTypeMerge defaultFunctor
isOptionType mkOptionType;
inherit (asserts)
assertMsg assertOneOf;
inherit (debug) addErrorContextToAttrs traceIf traceVal traceValFn
traceXMLVal traceXMLValMarked traceSeq traceSeqN traceValSeq
traceValSeqFn traceValSeqN traceValSeqNFn traceShowVal

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@ -509,7 +509,7 @@ rec {
=> 3
*/
last = list:
assert assertMsg (list != []) "lists.last: list must not be empty!";
assert lib.assertMsg (list != []) "lists.last: list must not be empty!";
elemAt list (length list - 1);
/* Return all elements but the last
@ -519,7 +519,7 @@ rec {
=> [ 1 2 ]
*/
init = list:
assert assertMsg (list != []) "lists.init: list must not be empty!";
assert lib.assertMsg (list != []) "lists.init: list must not be empty!";
take (length list - 1) list;

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@ -171,7 +171,7 @@ rec {
builtins.fromJSON (builtins.readFile path);
## Warnings and asserts
## Warnings
/* See https://github.com/NixOS/nix/issues/749. Eventually we'd like these
to expand to Nix builtins that carry metadata so that Nix can filter out
@ -188,44 +188,6 @@ rec {
warn = msg: builtins.trace "WARNING: ${msg}";
info = msg: builtins.trace "INFO: ${msg}";
/* Print a trace message if pred is false.
Intended to be used to augment asserts with helpful error messages.
Example:
assertMsg false "nope"
=> false
stderr> trace: nope
assert (assertMsg ("foo" == "bar") "foo is not bar, silly"); ""
stderr> trace: foo is not bar, silly
stderr> assert failed at
Type:
assertMsg :: Bool -> String -> Bool
*/
# TODO(Profpatsch): add tests that check stderr
assertMsg = pred: msg:
if pred
then true
else builtins.trace msg false;
/* Specialized `assertMsg` for checking if val is one of the elements
of a list. Useful for checking enums.
Example:
let sslLibrary = "libressl"
in assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ]
=> false
stderr> trace: sslLibrary must be one of "openssl", "bearssl", but is: "libressl"
Type:
assertOneOf :: String -> ComparableVal -> List ComparableVal -> Bool
*/
assertOneOf = name: val: xs: assertMsg
(lib.elem val xs)
"${name} must be one of ${
lib.generators.toPretty {} xs}, but is: ${
lib.generators.toPretty {} val}";
## Function annotations

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@ -441,7 +441,7 @@ rec {
# Either value of type `finalType` or `coercedType`, the latter is
# converted to `finalType` using `coerceFunc`.
coercedTo = coercedType: coerceFunc: finalType:
assert assertMsg (coercedType.getSubModules == null)
assert lib.assertMsg (coercedType.getSubModules == null)
"coercedTo: coercedType must not have submodules (its a ${
coercedType.description})";
mkOptionType rec {