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Show precise error messages in option merge failures 

For instance, if time.timeZone is defined multiple times, you now get
the error message:

  error: user-thrown exception: The unique option `time.timeZone' is defined multiple times, in `/etc/nixos/configurations/misc/eelco/x11vnc.nix' and `/etc/nixos/configuration.nix'.

while previously you got:

  error: user-thrown exception: Multiple definitions of string. Only one is allowed for this option.

and only an inspection of the stack trace gave a clue as to what
option caused the problem.
This commit is contained in:
Eelco Dolstra 2013-10-28 19:48:30 +01:00
parent dbefab9cf4
commit 73f32d0375
6 changed files with 58 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
lib/modules.nix
View File

@ -128,7 +128,7 @@ rec {
opt.options ? apply && res ? apply ||
opt.options ? type && res ? type
then
throw "The option `${showOption loc}' in `${opt.file}' is already declared in ${concatStringsSep " and " (map (d: "`${d}'") res.declarations)}."
throw "The option `${showOption loc}' in `${opt.file}' is already declared in ${showFiles res.declarations}."
else
opt.options // res //
{ declarations = [opt.file] ++ res.declarations;
@ -153,7 +153,7 @@ rec {
fold (def: res:
if opt.type.check def.value then res
else throw "The option value `${showOption loc}' in `${def.file}' is not a ${opt.type.name}.")
(opt.type.merge' { prefix = loc; } (map (m: m.value) defsFinal)) defsFinal;
(opt.type.merge { prefix = loc; files = map (m: m.file) defsFinal; } (map (m: m.value) defsFinal)) defsFinal;
# Finally, apply the ‘apply’ function to the merged
# value. This allows options to yield a value computed
# from the definitions.

17
lib/options.nix
View File

@ -55,21 +55,20 @@ rec {
}
) (attrNames defs));
mergeDefaultOption = list:
mergeDefaultOption = args: list:
if length list == 1 then head list
else if all builtins.isFunction list then x: mergeDefaultOption (map (f: f x) list)
else if all builtins.isFunction list then x: mergeDefaultOption args (map (f: f x) list)
else if all isList list then concatLists list
else if all isAttrs list then fold lib.mergeAttrs {} list
else if all builtins.isBool list then fold lib.or false list
else if all builtins.isString list then lib.concatStrings list
else if all builtins.isInt list && all (x: x == head list) list
then head list
else throw "Cannot merge values.";
else if all builtins.isInt list && all (x: x == head list) list then head list
else throw "Cannot merge definitions of `${showOption args.prefix}' given in ${showFiles args.files}.";
/* Obsolete, will remove soon. Specify an option type or apply
function instead. */
mergeTypedOption = typeName: predicate: merge: list:
mergeTypedOption = typeName: predicate: merge: args: list:
if all predicate list then merge list
else throw "Expect a ${typeName}.";
@ -82,9 +81,10 @@ rec {
(x: if builtins ? isString then builtins.isString x else x + "")
lib.concatStrings;
mergeOneOption = list:
mergeOneOption = args: list:
if list == [] then abort "This case should never happen."
else if length list != 1 then throw "Multiple definitions. Only one is allowed for this option."
else if length list != 1 then
throw "The unique option `${showOption args.prefix}' is defined multiple times, in ${showFiles args.files}."
else head list;
@ -135,6 +135,7 @@ rec {
/* Helper functions. */
showOption = concatStringsSep ".";
showFiles = files: concatStringsSep " and " (map (f: "`${f}'") files);
unknownModule = "<unknown-file>";
}

76
lib/types.nix
View File

@ -19,27 +19,24 @@ rec {
};
# name (name of the type)
# check (check the config value)
# merge (default merge function)
# getSubOptions (returns sub-options for manual generation)
isOptionType = isType "option-type";
mkOptionType =
{ name
, check ? (x: true)
, merge ? mergeDefaultOption
, merge' ? args: merge
, getSubOptions ? prefix: {}
{ # Human-readable representation of the type.
name
, # Function applied to each definition that should return true if
# its type-correct, false otherwise.
check ? (x: true)
, # Merge a list of definitions together into a single value.
merge ? mergeDefaultOption
, # Return a flat list of sub-options. Used to generate
# documentation.
getSubOptions ? prefix: {}
}:
{ _type = "option-type";
inherit name check merge merge' getSubOptions;
inherit name check merge getSubOptions;
};
addToPrefix = args: name: args // { prefix = args.prefix ++ [name]; };
types = rec {
unspecified = mkOptionType {
@ -49,7 +46,7 @@ rec {
bool = mkOptionType {
name = "boolean";
check = builtins.isBool;
merge = fold lib.or false;
merge = args: fold lib.or false;
};
int = mkOptionType {
@ -60,7 +57,7 @@ rec {
string = mkOptionType {
name = "string";
check = builtins.isString;
merge = lib.concatStrings;
merge = args: lib.concatStrings;
};
# Like ‘string’, but add newlines between every value. Useful for
@ -68,54 +65,56 @@ rec {
lines = mkOptionType {
name = "string";
check = builtins.isString;
merge = lib.concatStringsSep "\n";
merge = args: lib.concatStringsSep "\n";
};
commas = mkOptionType {
name = "string";
check = builtins.isString;
merge = lib.concatStringsSep ",";
merge = args: lib.concatStringsSep ",";
};
envVar = mkOptionType {
name = "environment variable";
inherit (string) check;
merge = lib.concatStringsSep ":";
merge = args: lib.concatStringsSep ":";
};
attrs = mkOptionType {
name = "attribute set";
check = isAttrs;
merge = fold lib.mergeAttrs {};
merge = args: fold lib.mergeAttrs {};
};
# derivation is a reserved keyword.
package = mkOptionType {
name = "derivation";
check = isDerivation;
merge = mergeOneOption;
};
path = mkOptionType {
name = "path";
# Hacky: there is no ‘isPath’ primop.
check = x: builtins.unsafeDiscardStringContext (builtins.substring 0 1 (toString x)) == "/";
merge = mergeOneOption;
};
# drop this in the future:
list = builtins.trace "types.list is deprecated; use types.listOf instead" types.listOf;
list = builtins.trace "`types.list' is deprecated; use `types.listOf' instead" types.listOf;
listOf = elemType: mkOptionType {
name = "list of ${elemType.name}s";
check = value: isList value && all elemType.check value;
merge' = args: defs: imap (n: def: elemType.merge' (addToPrefix args (toString n)) [def]) (concatLists defs);
merge = args: defs: imap (n: def: elemType.merge (addToPrefix args (toString n)) [def]) (concatLists defs);
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["*"]);
};
attrsOf = elemType: mkOptionType {
name = "attribute set of ${elemType.name}s";
check = x: isAttrs x && all elemType.check (lib.attrValues x);
merge' = args: lib.zipAttrsWith (name:
elemType.merge' (addToPrefix (args // { inherit name; }) name));
merge = args: lib.zipAttrsWith (name:
elemType.merge (addToPrefix (args // { inherit name; }) name));
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name>"]);
};
@ -138,43 +137,39 @@ rec {
if isList x then listOnly.check x
else if isAttrs x then attrOnly.check x
else false;
merge' = args: defs: attrOnly.merge' args (imap convertIfList defs);
merge = args: defs: attrOnly.merge args (imap convertIfList defs);
getSubOptions = prefix: elemType.getSubOptions (prefix ++ ["<name?>"]);
};
uniq = elemType: mkOptionType {
inherit (elemType) name check;
merge = list:
if length list == 1 then
head list
else
throw "Multiple definitions of ${elemType.name}. Only one is allowed for this option.";
merge = mergeOneOption;
getSubOptions = elemType.getSubOptions;
};
none = elemType: mkOptionType {
inherit (elemType) name check;
merge = list:
throw "No definitions are allowed for this option.";
merge = args: list:
throw "No definitions are allowed for the option `${showOption args.prefix}'.";
getSubOptions = elemType.getSubOptions;
};
nullOr = elemType: mkOptionType {
name = "null or ${elemType.name}";
check = x: builtins.isNull x || elemType.check x;
merge' = args: defs:
merge = args: defs:
if all isNull defs then null
else if any isNull defs then
throw "Some but not all values are null."
else elemType.merge' args defs;
throw "The option `${showOption args.prefix}' is defined both null and not null, in ${showFiles args.files}."
else elemType.merge args defs;
getSubOptions = elemType.getSubOptions;
};
functionTo = elemType: mkOptionType {
name = "function that evaluates to a(n) ${elemType.name}";
check = builtins.isFunction;
merge' = args: fns:
fnArgs: elemType.merge' args (map (fn: fn fnArgs) fns);
merge = args: fns:
fnArgs: elemType.merge args (map (fn: fn fnArgs) fns);
getSubOptions = elemType.getSubOptions;
};
@ -183,8 +178,7 @@ rec {
mkOptionType rec {
name = "submodule";
check = x: isAttrs x || builtins.isFunction x;
merge = merge' {};
merge' = args: defs:
merge = args: defs:
let
coerce = def: if builtins.isFunction def then def else { config = def; };
modules = opts' ++ map coerce defs;
@ -204,4 +198,8 @@ rec {
};
/* Helper function. */
addToPrefix = args: name: args // { prefix = args.prefix ++ [name]; };
}

9
nixos/modules/config/shells-environment.nix
View File

@ -25,11 +25,14 @@ in
'';
type = types.attrsOf (mkOptionType {
name = "a string or a list of strings";
merge = xs:
merge = args: xs:
let xs' = filterOverrides xs; in
if isList (head xs') then concatLists xs'
else if builtins.lessThan 1 (length xs') then abort "variable in ‘environment.variables’ has multiple values"
else if !builtins.isString (head xs') then abort "variable in ‘environment.variables’ does not have a string value"
else if builtins.lessThan 1 (length xs') then
# Don't show location info here, since it's too general.
throw "The option `${showOption args.prefix}' is defined multiple times."
else if !builtins.isString (head xs') then
throw "The option `${showOption args.prefix}' does not have a string value."
else head xs';
});
apply = mapAttrs (n: v: if isList v then concatStringsSep ":" v else v);

2
nixos/modules/config/sysctl.nix
View File

@ -7,7 +7,7 @@ let
sysctlOption = mkOptionType {
name = "sysctl option value";
check = x: builtins.isBool x || builtins.isString x || builtins.isInt x;
merge = xs: last xs; # FIXME: hacky way to allow overriding in configuration.nix.
merge = args: xs: last xs; # FIXME: hacky way to allow overriding in configuration.nix.
};
in

2
nixos/modules/misc/nixpkgs.nix
View File

@ -26,7 +26,7 @@ let
configType = mkOptionType {
name = "nixpkgs config";
check = traceValIfNot isConfig;
merge = fold mergeConfig {};
merge = args: fold mergeConfig {};
};
in