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nixpkgs/lib/deprecated.nix
Graham Christensen 152c63c9ff
Convert libs to a fixed-point
This does break the API of being able to import any lib file and get
its libs, however I'm not sure people did this.

I made this while exploring being able to swap out docFn with a stub
in #2305, to avoid functor performance problems. I don't know if that
is going to move forward (or if it is a problem or not,) but after
doing all this work figured I'd put it up anyway :)

Two notable advantages to this approach:

1. when a lib inherits another lib's functions, it doesn't
   automatically get put in to the scope of lib
2. when a lib implements a new obscure functions, it doesn't
   automatically get put in to the scope of lib

Using the test script (later in this commit) I got the following diff
on the API:

  + diff master fixed-lib
  11764a11765,11766
  > .types.defaultFunctor
  > .types.defaultTypeMerge
  11774a11777,11778
  > .types.isOptionType
  > .types.isType
  11781a11786
  > .types.mkOptionType
  11788a11794
  > .types.setType
  11795a11802
  > .types.types

This means that this commit _adds_ to the API, however I can't find a
way to fix these last remaining discrepancies. At least none are
_removed_.

Test script (run with nix-repl in the PATH):

  #!/bin/sh

  set -eux

  repl() {
      suff=${1:-}
      echo "(import ./lib)$suff" \
          | nix-repl 2>&1
  }

  attrs_to_check() {
      repl "${1:-}" \
          | tr ';'  $'\n' \
          | grep "\.\.\." \
          | cut -d' ' -f2 \
          | sed -e "s/^/${1:-}./" \
          | sort
  }

  summ() {
      repl "${1:-}" \
          | tr ' ' $'\n' \
          | sort \
          | uniq
  }

  deep_summ() {
      suff="${1:-}"
      depth="${2:-4}"
      depth=$((depth - 1))
      summ "$suff"

      for attr in $(attrs_to_check "$suff" | grep -v "types.types"); do
          if [ $depth -eq 0 ]; then
              summ "$attr" | sed -e "s/^/$attr./"
          else
              deep_summ "$attr" "$depth" | sed -e "s/^/$attr./"
          fi
      done
  }

  (
      cd nixpkgs

      #git add .
      #git commit -m "Auto-commit, sorry" || true
      git checkout fixed-lib
      deep_summ > ../fixed-lib
      git checkout master
      deep_summ > ../master
  )

  if diff master fixed-lib; then
      echo "SHALLOW MATCH!"
  fi

  (
      cd nixpkgs
      git checkout fixed-lib
      repl .types
  )
2017-09-16 21:36:43 -04:00

394 lines
16 KiB
Nix

{ lib }:
let
inherit (builtins) isFunction head tail isList isAttrs isInt attrNames;
in
with lib.lists;
with lib.attrsets;
with lib.strings;
rec {
# returns default if env var is not set
maybeEnv = name: default:
let value = builtins.getEnv name; in
if value == "" then default else value;
defaultMergeArg = x : y: if builtins.isAttrs y then
y
else
(y x);
defaultMerge = x: y: x // (defaultMergeArg x y);
foldArgs = merger: f: init: x:
let arg = (merger init (defaultMergeArg init x));
# now add the function with composed args already applied to the final attrs
base = (setAttrMerge "passthru" {} (f arg)
( z: z // rec {
function = foldArgs merger f arg;
args = (lib.attrByPath ["passthru" "args"] {} z) // x;
} ));
withStdOverrides = base // {
override = base.passthru.function;
};
in
withStdOverrides;
# predecessors: proposed replacement for applyAndFun (which has a bug cause it merges twice)
# the naming "overridableDelayableArgs" tries to express that you can
# - override attr values which have been supplied earlier
# - use attr values before they have been supplied by accessing the fix point
# name "fixed"
# f: the (delayed overridden) arguments are applied to this
#
# initial: initial attrs arguments and settings. see defaultOverridableDelayableArgs
#
# returns: f applied to the arguments // special attributes attrs
# a) merge: merge applied args with new args. Wether an argument is overridden depends on the merge settings
# b) replace: this let's you replace and remove names no matter which merge function has been set
#
# examples: see test cases "res" below;
overridableDelayableArgs =
f: # the function applied to the arguments
initial: # you pass attrs, the functions below are passing a function taking the fix argument
let
takeFixed = if isFunction initial then initial else (fixed : initial); # transform initial to an expression always taking the fixed argument
tidy = args:
let # apply all functions given in "applyPreTidy" in sequence
applyPreTidyFun = fold ( n: a: x: n ( a x ) ) lib.id (maybeAttr "applyPreTidy" [] args);
in removeAttrs (applyPreTidyFun args) ( ["applyPreTidy"] ++ (maybeAttr "removeAttrs" [] args) ); # tidy up args before applying them
fun = n: x:
let newArgs = fixed:
let args = takeFixed fixed;
mergeFun = args.${n};
in if isAttrs x then (mergeFun args x)
else assert isFunction x;
mergeFun args (x ( args // { inherit fixed; }));
in overridableDelayableArgs f newArgs;
in
(f (tidy (lib.fix takeFixed))) // {
merge = fun "mergeFun";
replace = fun "keepFun";
};
defaultOverridableDelayableArgs = f:
let defaults = {
mergeFun = mergeAttrByFunc; # default merge function. merge strategie (concatenate lists, strings) is given by mergeAttrBy
keepFun = a: b: { inherit (a) removeAttrs mergeFun keepFun mergeAttrBy; } // b; # even when using replace preserve these values
applyPreTidy = []; # list of functions applied to args before args are tidied up (usage case : prepareDerivationArgs)
mergeAttrBy = mergeAttrBy // {
applyPreTidy = a: b: a ++ b;
removeAttrs = a: b: a ++ b;
};
removeAttrs = ["mergeFun" "keepFun" "mergeAttrBy" "removeAttrs" "fixed" ]; # before applying the arguments to the function make sure these names are gone
};
in (overridableDelayableArgs f defaults).merge;
# rec { # an example of how composedArgsAndFun can be used
# a = composedArgsAndFun (x: x) { a = ["2"]; meta = { d = "bar";}; };
# # meta.d will be lost ! It's your task to preserve it (eg using a merge function)
# b = a.passthru.function { a = [ "3" ]; meta = { d2 = "bar2";}; };
# # instead of passing/ overriding values you can use a merge function:
# c = b.passthru.function ( x: { a = x.a ++ ["4"]; }); # consider using (maybeAttr "a" [] x)
# }
# result:
# {
# a = { a = ["2"]; meta = { d = "bar"; }; passthru = { function = .. }; };
# b = { a = ["3"]; meta = { d2 = "bar2"; }; passthru = { function = .. }; };
# c = { a = ["3" "4"]; meta = { d2 = "bar2"; }; passthru = { function = .. }; };
# # c2 is equal to c
# }
composedArgsAndFun = f: foldArgs defaultMerge f {};
# shortcut for attrByPath ["name"] default attrs
maybeAttrNullable = maybeAttr;
# shortcut for attrByPath ["name"] default attrs
maybeAttr = name: default: attrs: attrs.${name} or default;
# Return the second argument if the first one is true or the empty version
# of the second argument.
ifEnable = cond: val:
if cond then val
else if builtins.isList val then []
else if builtins.isAttrs val then {}
# else if builtins.isString val then ""
else if val == true || val == false then false
else null;
# Return true only if there is an attribute and it is true.
checkFlag = attrSet: name:
if name == "true" then true else
if name == "false" then false else
if (elem name (attrByPath ["flags"] [] attrSet)) then true else
attrByPath [name] false attrSet ;
# Input : attrSet, [ [name default] ... ], name
# Output : its value or default.
getValue = attrSet: argList: name:
( attrByPath [name] (if checkFlag attrSet name then true else
if argList == [] then null else
let x = builtins.head argList; in
if (head x) == name then
(head (tail x))
else (getValue attrSet
(tail argList) name)) attrSet );
# Input : attrSet, [[name default] ...], [ [flagname reqs..] ... ]
# Output : are reqs satisfied? It's asserted.
checkReqs = attrSet: argList: condList:
(
fold lib.and true
(map (x: let name = (head x); in
((checkFlag attrSet name) ->
(fold lib.and true
(map (y: let val=(getValue attrSet argList y); in
(val!=null) && (val!=false))
(tail x))))) condList));
# This function has O(n^2) performance.
uniqList = { inputList, acc ? [] }:
let go = xs: acc:
if xs == []
then []
else let x = head xs;
y = if elem x acc then [] else [x];
in y ++ go (tail xs) (y ++ acc);
in go inputList acc;
uniqListExt = { inputList,
outputList ? [],
getter ? (x: x),
compare ? (x: y: x==y) }:
if inputList == [] then outputList else
let x = head inputList;
isX = y: (compare (getter y) (getter x));
newOutputList = outputList ++
(if any isX outputList then [] else [x]);
in uniqListExt { outputList = newOutputList;
inputList = (tail inputList);
inherit getter compare;
};
condConcat = name: list: checker:
if list == [] then name else
if checker (head list) then
condConcat
(name + (head (tail list)))
(tail (tail list))
checker
else condConcat
name (tail (tail list)) checker;
lazyGenericClosure = {startSet, operator}:
let
work = list: doneKeys: result:
if list == [] then
result
else
let x = head list; key = x.key; in
if elem key doneKeys then
work (tail list) doneKeys result
else
work (tail list ++ operator x) ([key] ++ doneKeys) ([x] ++ result);
in
work startSet [] [];
innerModifySumArgs = f: x: a: b: if b == null then (f a b) // x else
innerModifySumArgs f x (a // b);
modifySumArgs = f: x: innerModifySumArgs f x {};
innerClosePropagation = acc: xs:
if xs == []
then acc
else let y = head xs;
ys = tail xs;
in if ! isAttrs y
then innerClosePropagation acc ys
else let acc' = [y] ++ acc;
in innerClosePropagation
acc'
(uniqList { inputList = (maybeAttrNullable "propagatedBuildInputs" [] y)
++ (maybeAttrNullable "propagatedNativeBuildInputs" [] y)
++ ys;
acc = acc';
}
);
closePropagation = list: (uniqList {inputList = (innerClosePropagation [] list);});
# calls a function (f attr value ) for each record item. returns a list
mapAttrsFlatten = f: r: map (attr: f attr r.${attr}) (attrNames r);
# attribute set containing one attribute
nvs = name: value: listToAttrs [ (nameValuePair name value) ];
# adds / replaces an attribute of an attribute set
setAttr = set: name: v: set // (nvs name v);
# setAttrMerge (similar to mergeAttrsWithFunc but only merges the values of a particular name)
# setAttrMerge "a" [] { a = [2];} (x: x ++ [3]) -> { a = [2 3]; }
# setAttrMerge "a" [] { } (x: x ++ [3]) -> { a = [ 3]; }
setAttrMerge = name: default: attrs: f:
setAttr attrs name (f (maybeAttr name default attrs));
# Using f = a: b = b the result is similar to //
# merge attributes with custom function handling the case that the attribute
# exists in both sets
mergeAttrsWithFunc = f: set1: set2:
fold (n: set: if set ? ${n}
then setAttr set n (f set.${n} set2.${n})
else set )
(set2 // set1) (attrNames set2);
# merging two attribute set concatenating the values of same attribute names
# eg { a = 7; } { a = [ 2 3 ]; } becomes { a = [ 7 2 3 ]; }
mergeAttrsConcatenateValues = mergeAttrsWithFunc ( a: b: (toList a) ++ (toList b) );
# merges attributes using //, if a name exists in both attributes
# an error will be triggered unless its listed in mergeLists
# so you can mergeAttrsNoOverride { buildInputs = [a]; } { buildInputs = [a]; } {} to get
# { buildInputs = [a b]; }
# merging buildPhase doesn't really make sense. The cases will be rare where appending /prefixing will fit your needs?
# in these cases the first buildPhase will override the second one
# ! deprecated, use mergeAttrByFunc instead
mergeAttrsNoOverride = { mergeLists ? ["buildInputs" "propagatedBuildInputs"],
overrideSnd ? [ "buildPhase" ]
}: attrs1: attrs2:
fold (n: set:
setAttr set n ( if set ? ${n}
then # merge
if elem n mergeLists # attribute contains list, merge them by concatenating
then attrs2.${n} ++ attrs1.${n}
else if elem n overrideSnd
then attrs1.${n}
else throw "error mergeAttrsNoOverride, attribute ${n} given in both attributes - no merge func defined"
else attrs2.${n} # add attribute not existing in attr1
)) attrs1 (attrNames attrs2);
# example usage:
# mergeAttrByFunc {
# inherit mergeAttrBy; # defined below
# buildInputs = [ a b ];
# } {
# buildInputs = [ c d ];
# };
# will result in
# { mergeAttrsBy = [...]; buildInputs = [ a b c d ]; }
# is used by prepareDerivationArgs, defaultOverridableDelayableArgs and can be used when composing using
# foldArgs, composedArgsAndFun or applyAndFun. Example: composableDerivation in all-packages.nix
mergeAttrByFunc = x: y:
let
mergeAttrBy2 = { mergeAttrBy = lib.mergeAttrs; }
// (maybeAttr "mergeAttrBy" {} x)
// (maybeAttr "mergeAttrBy" {} y); in
fold lib.mergeAttrs {} [
x y
(mapAttrs ( a: v: # merge special names using given functions
if x ? ${a}
then if y ? ${a}
then v x.${a} y.${a} # both have attr, use merge func
else x.${a} # only x has attr
else y.${a} # only y has attr)
) (removeAttrs mergeAttrBy2
# don't merge attrs which are neither in x nor y
(filter (a: ! x ? ${a} && ! y ? ${a})
(attrNames mergeAttrBy2))
)
)
];
mergeAttrsByFuncDefaults = foldl mergeAttrByFunc { inherit mergeAttrBy; };
mergeAttrsByFuncDefaultsClean = list: removeAttrs (mergeAttrsByFuncDefaults list) ["mergeAttrBy"];
# sane defaults (same name as attr name so that inherit can be used)
mergeAttrBy = # { buildInputs = concatList; [...]; passthru = mergeAttr; [..]; }
listToAttrs (map (n: nameValuePair n lib.concat)
[ "nativeBuildInputs" "buildInputs" "propagatedBuildInputs" "configureFlags" "prePhases" "postAll" "patches" ])
// listToAttrs (map (n: nameValuePair n lib.mergeAttrs) [ "passthru" "meta" "cfg" "flags" ])
// listToAttrs (map (n: nameValuePair n (a: b: "${a}\n${b}") ) [ "preConfigure" "postInstall" ])
;
# prepareDerivationArgs tries to make writing configurable derivations easier
# example:
# prepareDerivationArgs {
# mergeAttrBy = {
# myScript = x: y: x ++ "\n" ++ y;
# };
# cfg = {
# readlineSupport = true;
# };
# flags = {
# readline = {
# set = {
# configureFlags = [ "--with-compiler=${compiler}" ];
# buildInputs = [ compiler ];
# pass = { inherit compiler; READLINE=1; };
# assertion = compiler.dllSupport;
# myScript = "foo";
# };
# unset = { configureFlags = ["--without-compiler"]; };
# };
# };
# src = ...
# buildPhase = '' ... '';
# name = ...
# myScript = "bar";
# };
# if you don't have need for unset you can omit the surrounding set = { .. } attr
# all attrs except flags cfg and mergeAttrBy will be merged with the
# additional data from flags depending on config settings
# It's used in composableDerivation in all-packages.nix. It's also used
# heavily in the new python and libs implementation
#
# should we check for misspelled cfg options?
# TODO use args.mergeFun here as well?
prepareDerivationArgs = args:
let args2 = { cfg = {}; flags = {}; } // args;
flagName = name: "${name}Support";
cfgWithDefaults = (listToAttrs (map (n: nameValuePair (flagName n) false) (attrNames args2.flags)))
// args2.cfg;
opts = attrValues (mapAttrs (a: v:
let v2 = if v ? set || v ? unset then v else { set = v; };
n = if cfgWithDefaults.${flagName a} then "set" else "unset";
attr = maybeAttr n {} v2; in
if (maybeAttr "assertion" true attr)
then attr
else throw "assertion of flag ${a} of derivation ${args.name} failed"
) args2.flags );
in removeAttrs
(mergeAttrsByFuncDefaults ([args] ++ opts ++ [{ passthru = cfgWithDefaults; }]))
["flags" "cfg" "mergeAttrBy" ];
nixType = x:
if isAttrs x then
if x ? outPath then "derivation"
else "attrs"
else if isFunction x then "function"
else if isList x then "list"
else if x == true then "bool"
else if x == false then "bool"
else if x == null then "null"
else if isInt x then "int"
else "string";
/* deprecated:
For historical reasons, imap has an index starting at 1.
But for consistency with the rest of the library we want an index
starting at zero.
*/
imap = imap1;
}