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nixpkgs/lib/debug.nix

99 lines
4.2 KiB

let lib = import ./default.nix;
inherit (builtins) trace attrNamesToStr isAttrs isFunction isList isInt
isString isBool head substring attrNames;
inherit (lib) all id mapAttrsFlatten elem;
in
rec {
inherit (builtins) addErrorContext;
addErrorContextToAttrs = lib.mapAttrs (a: v: lib.addErrorContext "while evaluating ${a}" v);
traceIf = p: msg: x: if p then trace msg x else x;
traceVal = x: trace x x;
traceXMLVal = x: trace (builtins.toXML x) x;
traceXMLValMarked = str: x: trace (str + builtins.toXML x) x;
# strict trace functions (traced structure is fully evaluated and printed)
traceSeq = x: y: trace (builtins.deepSeq x x) y;
traceValSeq = v: traceVal (builtins.deepSeq v v);
# this can help debug your code as well - designed to not produce thousands of lines
traceShowVal = x: trace (showVal x) x;
traceShowValMarked = str: x: trace (str + showVal x) x;
attrNamesToStr = a: lib.concatStringsSep "; " (map (x: "${x}=") (attrNames a));
showVal = x:
if isAttrs x then
if x ? outPath then "x is a derivation, name ${if x ? name then x.name else "<no name>"}, { ${attrNamesToStr x} }"
else "x is attr set { ${attrNamesToStr x} }"
else if isFunction x then "x is a function"
else if x == [] then "x is an empty list"
else if isList x then "x is a list, first element is: ${showVal (head x)}"
else if x == true then "x is boolean true"
else if x == false then "x is boolean false"
else if x == null then "x is null"
else if isInt x then "x is an integer `${toString x}'"
else if isString x then "x is a string `${substring 0 50 x}...'"
else "x is probably a path `${substring 0 50 (toString x)}...'";
# trace the arguments passed to function and its result
# maybe rewrite these functions in a traceCallXml like style. Then one function is enough
traceCall = n: f: a: let t = n2: x: traceShowValMarked "${n} ${n2}:" x; in t "result" (f (t "arg 1" a));
traceCall2 = n: f: a: b: let t = n2: x: traceShowValMarked "${n} ${n2}:" x; in t "result" (f (t "arg 1" a) (t "arg 2" b));
traceCall3 = n: f: a: b: c: let t = n2: x: traceShowValMarked "${n} ${n2}:" x; in t "result" (f (t "arg 1" a) (t "arg 2" b) (t "arg 3" c));
# FIXME: rename this?
traceValIfNot = c: x:
if c x then true else trace (showVal x) false;
/* Evaluate a set of tests. A test is an attribute set {expr,
expected}, denoting an expression and its expected result. The
result is a list of failed tests, each represented as {name,
expected, actual}, denoting the attribute name of the failing
test and its expected and actual results. Used for regression
testing of the functions in lib; see tests.nix for an example.
Only tests having names starting with "test" are run.
Add attr { tests = ["testName"]; } to run these test only
*/
runTests = tests: lib.concatLists (lib.attrValues (lib.mapAttrs (name: test:
let testsToRun = if tests ? tests then tests.tests else [];
in if (substring 0 4 name == "test" || elem name testsToRun)
&& ((testsToRun == []) || elem name tests.tests)
&& (test.expr != test.expected)
then [ { inherit name; expected = test.expected; result = test.expr; } ]
else [] ) tests));
# create a test assuming that list elements are true
# usage: { testX = allTrue [ true ]; }
testAllTrue = expr: { inherit expr; expected = map (x: true) expr; };
strict = v:
trace "Warning: strict is deprecated and will be removed in the next release"
(builtins.seq v v);
# example: (traceCallXml "myfun" id 3) will output something like
# calling myfun arg 1: 3 result: 3
# this forces deep evaluation of all arguments and the result!
# note: if result doesn't evaluate you'll get no trace at all (FIXME)
# args should be printed in any case
traceCallXml = a:
if !isInt a then
traceCallXml 1 "calling ${a}\n"
else
let nr = a;
in (str: expr:
if isFunction expr then
(arg:
traceCallXml (builtins.add 1 nr) "${str}\n arg ${builtins.toString nr} is \n ${builtins.toXML (strict arg)}" (expr arg)
)
else
let r = strict expr;
in trace "${str}\n result:\n${builtins.toXML r}" r
);
}