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let inherit (lib.strings) concatStringsSep ; inherit (lib.lists) filter ; inherit (lib.trivial) showWarnings ;inrec {
/** Throw if `pred` is false, else return `pred`. Intended to be used to augment asserts with helpful error messages.
# Inputs
`pred`
: Predicate that needs to succeed, otherwise `msg` is thrown
`msg`
: Message to throw in case `pred` fails
# Type
``` assertMsg :: Bool -> String -> Bool ```
# Examples :::{.example} ## `lib.asserts.assertMsg` usage example
```nix assertMsg false "nope" stderr> error: nope assert assertMsg ("foo" == "bar") "foo is not bar, silly"; "" stderr> error: foo is not bar, silly ```
::: */ # TODO(Profpatsch): add tests that check stderr assertMsg = pred: msg: pred || throw msg;
/** Specialized `assertMsg` for checking if `val` is one of the elements of the list `xs`. Useful for checking enums.
# Inputs
`name`
: The name of the variable the user entered `val` into, for inclusion in the error message
`val`
: The value of what the user provided, to be compared against the values in `xs`
`xs`
: The list of valid values
# Type
``` assertOneOf :: String -> ComparableVal -> [ComparableVal] -> Bool ```
# Examples :::{.example} ## `lib.asserts.assertOneOf` usage example
```nix let sslLibrary = "libressl"; in assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ] stderr> error: sslLibrary must be one of [ stderr> "openssl" stderr> "bearssl" stderr> ], but is: "libressl" ```
::: */ assertOneOf = name: val: xs: assertMsg (lib.elem val xs) "${name} must be one of ${lib.generators.toPretty { } xs}, but is: ${ lib.generators.toPretty { } val }";
/** Specialized `assertMsg` for checking if every one of `vals` is one of the elements of the list `xs`. Useful for checking lists of supported attributes.
# Inputs
`name`
: The name of the variable the user entered `val` into, for inclusion in the error message
`vals`
: The list of values of what the user provided, to be compared against the values in `xs`
`xs`
: The list of valid values
# Type
``` assertEachOneOf :: String -> [ComparableVal] -> [ComparableVal] -> Bool ```
# Examples :::{.example} ## `lib.asserts.assertEachOneOf` usage example
```nix let sslLibraries = [ "libressl" "bearssl" ]; in assertEachOneOf "sslLibraries" sslLibraries [ "openssl" "bearssl" ] stderr> error: each element in sslLibraries must be one of [ stderr> "openssl" stderr> "bearssl" stderr> ], but is: [ stderr> "libressl" stderr> "bearssl" stderr> ] ```
::: */ assertEachOneOf = name: vals: xs: assertMsg (lib.all (val: lib.elem val xs) vals) "each element in ${name} must be one of ${lib.generators.toPretty { } xs}, but is: ${ lib.generators.toPretty { } vals }";
/** Wrap a value with logic that throws an error when assertions fail and emits any warnings.
# Inputs
`assertions`
: A list of assertions. If any of their `assertion` attrs is `false`, their `message` attrs will be emitted in a `throw`.
`warnings`
: A list of strings to emit as warnings. This function does no filtering on this list.
`val`
: A value to return, wrapped in `warn`, if a `throw` is not necessary.
# Type
``` checkAssertWarn :: [{ assertion :: Bool; message :: String; }] -> [String] -> a -> a ```
# Examples :::{.example} ## `lib.asserts.checkAssertWarn` usage example ```nix checkAssertWarn [ { assertion = false; message = "Will fail"; } ] [ ] null stderr> error: stderr> Failed assertions: stderr> - Will fail
checkAssertWarn [ { assertion = true; message = "Will not fail"; } ] [ "Will warn" ] null stderr> evaluation warning: Will warn null ```
::: */ checkAssertWarn = assertions: warnings: val: let failedAssertions = map (x: x.message) (filter (x: !x.assertion) assertions); in if failedAssertions != [ ] then throw "\nFailed assertions:\n${concatStringsSep "\n" (map (x: "- ${x}") failedAssertions)}" else showWarnings warnings val;
}