Move pkgs/lib/ to lib/

1 files changed, 119 insertions, 0 deletions

diff --git a/lib/debug.nix b/lib/debug.nix
new file mode 100644
index 00000000000..d627bc861ab
--- /dev/null
+++ b/lib/debug.nix
@@ -0,0 +1,119 @@
+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 {
+
+
+  # Wrapper aroung the primop `addErrorContext', which shouldn't used
+  # directly.  It evaluates and returns `val', but if an evaluation
+  # error occurs, the text in `msg' is added to the error context
+  # (stack trace) printed by Nix.
+  addErrorContext =
+    if builtins ? addErrorContext
+    then builtins.addErrorContext
+    else msg: val: val;
+
+  addErrorContextToAttrs = lib.mapAttrs (a : v : lib.addErrorContext "while evaluating ${a}" v);
+
+  
+  traceVal = if builtins ? trace then x: (builtins.trace x x) else x: x;
+  traceXMLVal = if builtins ? trace then x: (builtins.trace (builtins.toXML x) x) else x: x;
+  traceXMLValMarked = str: if builtins ? trace then x: (builtins.trace ( str + builtins.toXML x) x) else x: x;
+  
+  # this can help debug your code as well - designed to not produce thousands of lines
+  traceShowVal = x : trace (showVal x) x;
+  traceShowValMarked = str: x: trace (str + showVal x) x;
+  attrNamesToStr = a : lib.concatStringsSep "; " (map (x : "${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));
+
+  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; };
+
+  # evaluate everything once so that errors will occur earlier
+  # hacky: traverse attrs by adding a dummy
+  # ignores functions (should this behavior change?) See strictf
+  #
+  # Note: This should be a primop! Something like seq of haskell would be nice to
+  # have as well. It's used fore debugging only anyway
+  strict = x :
+    let
+        traverse = x :
+          if isString x then true
+          else if isAttrs x then
+            if x ? outPath then true
+            else all id (mapAttrsFlatten (n: traverse) x)
+          else if isList x then
+            all id (map traverse x)
+          else if isBool x then true
+          else if isFunction x then true
+          else if isInt x then true
+          else if x == null then true
+          else true; # a (store) path?
+    in if traverse x then x else throw "else never reached";
+
+  # 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 ${builtins.toXML (strict arg)}" (expr arg)
+            )
+          else 
+            let r = strict expr;
+            in builtins.trace "${str}\n result:\n${builtins.toXML r}" r
+      );
+}