added exception helper for modified after freeze

MANIFEST.in

@@ -3,6 +3,7 @@ graft docs
 include tox.ini
 include setup.py
 
+recursive-include src *.j2
 recursive-include docs *
 recursive-include misc *
 recursive-include tests *

requirements.txt

@@ -28,5 +28,6 @@ tornado==5.1.1
 tox==3.7.0
 tox-venv==0.3.1
 typing==3.6.6
+jinja2==2.10
 pep8-naming==0.8.2
-flake8==3.7.5
+flake8==3.7.5

setup.py

@@ -15,6 +15,7 @@
     "typing",
     "PyJWT",
     "cryptography",
+    "jinja2",
 ]
 
 setup(

src/inmanta/app.py

@@ -380,7 +380,7 @@ def _get_watched_file_handler(options):
 
 def _convert_to_log_level(level):
     if level >= len(log_levels):
-        level = 3
+        level = len(log_levels) - 1
     return log_levels[level]
 
 
@@ -452,6 +452,12 @@ def report(e):
         else:
             sys.excepthook(*sys.exc_info())
 
+        if isinstance(e, CompilerException):
+            from inmanta.compiler.help.explainer import ExplainerFactory
+            helpmsg = ExplainerFactory().explain_and_format(e)
+            if helpmsg is not None:
+                print(helpmsg)
+
     try:
         options.func(options)
     except CLIException as e:

src/inmanta/ast/__init__.py

@@ -16,11 +16,10 @@
     Contact: code@inmanta.com
 """
 
-from inmanta import util
-
 from typing import Dict, Sequence, List, Optional, Union  # noqa: F401
 from abc import abstractmethod
 import traceback
+from functools import lru_cache
 
 
 try:
@@ -31,11 +30,12 @@
 
 if TYPE_CHECKING:
     import inmanta.ast.statements  # noqa: F401
+    from inmanta.ast.attribute import Attribute  # noqa: F401
     from inmanta.ast.type import Type, NamedType  # noqa: F401
-    from inmanta.execute.runtime import ExecutionContext, Instance  # noqa: F401
-    from inmanta.ast.statements import Statement  # noqa: F401
+    from inmanta.execute.runtime import ExecutionContext, Instance, DelayedResultVariable  # noqa: F401
+    from inmanta.ast.statements import Statement, AssignStatement  # noqa: F401
     from inmanta.ast.entity import Entity  # noqa: F401
-    from inmanta.ast.statements.define import DefineImport  # noqa: F401
+    from inmanta.ast.statements.define import DefineImport, DefineEntity  # noqa: F401
 
 
 class Location(object):
@@ -77,7 +77,7 @@ def merge(self, other: Location) -> Location:
         assert isinstance(other, Location)
         assert self.file == other.file
 
-        if isinstance(other, Location):
+        if not isinstance(other, Range):
             return Location(self.file, min(self.lnr, other.lnr))
         else:
             if other.lnr < self.lnr:
@@ -135,7 +135,7 @@ class LocatableString(object):
         2. in the constructors of other statements
     """
 
-    def __init__(self, value, location: Range, lexpos: "int", namespace: "Namespace") -> None:
+    def __init__(self, value: str, location: Range, lexpos: "int", namespace: "Namespace") -> None:
         self.value = value
         self.location = location
 
@@ -147,13 +147,13 @@ def __init__(self, value, location: Range, lexpos: "int", namespace: "Namespace"
         self.lexpos = lexpos
         self.namespace = namespace
 
-    def get_value(self):
+    def get_value(self) -> str:
         return self.value
 
-    def get_location(self):
+    def get_location(self) -> Location:
         return self.location
 
-    def __str__(self):
+    def __str__(self) -> str:
         return self.value
 
 
@@ -438,7 +438,7 @@ def _get_ns(self, ns_parts: List[str]) -> "Optional[Namespace]":
                 return None
             return child._get_ns(ns_parts[1:])
 
-    @util.memoize
+    @lru_cache()
     def to_path(self) -> List[str]:
         """
             Return a list with the namespace path elements in it.
@@ -456,6 +456,7 @@ def get_location(self) -> Location:
 
 
 class CompilerException(Exception):
+    """ Base class for exceptions generated by the compiler"""
 
     def __init__(self, msg: str) -> None:
         Exception.__init__(self, msg)
@@ -483,7 +484,7 @@ def format(self) -> str:
         else:
             return self.get_message()
 
-    def format_trace(self, indent="", indent_level=0):
+    def format_trace(self, indent: str="", indent_level: int=0) -> str:
         """Make a representation of this exception and its causes"""
         out = indent * indent_level + self.format()
 
@@ -494,11 +495,12 @@ def format_trace(self, indent="", indent_level=0):
 
         return out
 
-    def __str__(self):
+    def __str__(self) -> str:
         return self.format()
 
 
 class RuntimeException(CompilerException):
+    """Baseclass for exceptions raised by the compiler after parsing is complete."""
 
     def __init__(self, stmt: "Optional[Locatable]", msg: str) -> None:
         CompilerException.__init__(self, msg)
@@ -507,7 +509,10 @@ def __init__(self, stmt: "Optional[Locatable]", msg: str) -> None:
             self.set_location(stmt.get_location())
             self.stmt = stmt
 
-    def set_statement(self, stmt: "Locatable", replace: bool = True):
+    def set_statement(self, stmt: "Locatable", replace: bool = True) -> None:
+        for cause in self.get_causes():
+            cause.set_statement(stmt, replace)
+
         if replace or self.stmt is None:
             self.set_location(stmt.get_location())
             self.stmt = stmt
@@ -520,6 +525,7 @@ def format(self) -> str:
 
 
 class TypeNotFoundException(RuntimeException):
+    """Exception raised when a type is referenced that does not exist"""
 
     def __init__(self, type: str, ns: Namespace) -> None:
         RuntimeException.__init__(self, stmt=None, msg="could not find type %s in namespace %s" % (type, ns))
@@ -534,6 +540,10 @@ def stringify_exception(exn: Exception) -> str:
 
 
 class ExternalException(RuntimeException):
+    """
+    When a plugin call produces an exception that is not a RuntimeException,
+    it is wrapped in an ExternalException to make it conform to the expected interface
+    """
 
     def __init__(self, stmt: Locatable, msg: str, cause: Exception) -> None:
         RuntimeException.__init__(self, stmt=stmt, msg=msg)
@@ -543,7 +553,7 @@ def __init__(self, stmt: Locatable, msg: str, cause: Exception) -> None:
     def get_causes(self) -> List[CompilerException]:
         return []
 
-    def format_trace(self, indent="", indent_level=0):
+    def format_trace(self, indent: str="", indent_level: int=0) -> str:
         """Make a representation of this exception and its causes"""
         out = indent * indent_level + self.format()
 
@@ -556,6 +566,7 @@ def format_trace(self, indent="", indent_level=0):
 
 
 class WrappingRuntimeException(RuntimeException):
+    """ Baseclass for RuntimeExceptions wrapping other RuntimeException """
 
     def __init__(self, stmt: Locatable, msg: str, cause: RuntimeException) -> None:
         if stmt is None and isinstance(cause, RuntimeException):
@@ -570,6 +581,7 @@ def get_causes(self) -> List[CompilerException]:
 
 
 class AttributeException(WrappingRuntimeException):
+    """ Exception raise when an attribute could not be set, always wraps another exception """
 
     def __init__(self, stmt: "Locatable", instance: "Instance", attribute: str, cause: RuntimeException) -> None:
         WrappingRuntimeException.__init__(
@@ -579,6 +591,7 @@ def __init__(self, stmt: "Locatable", instance: "Instance", attribute: str, caus
 
 
 class OptionalValueException(RuntimeException):
+    """Exception raised when an optional value is accessed that has no value (and is frozen)"""
 
     def __init__(self, instance: "Instance", attribute: str) -> None:
         RuntimeException.__init__(self, instance, "Optional variable accessed that has no value (%s.%s)" %
@@ -588,10 +601,12 @@ def __init__(self, instance: "Instance", attribute: str) -> None:
 
 
 class IndexException(RuntimeException):
+    """Exception raised when an index definition is invalid"""
     pass
 
 
 class TypingException(RuntimeException):
+    """Base class for exceptions raised during the typing phase of compilation"""
     pass
 
 
@@ -600,14 +615,16 @@ class KeyException(RuntimeException):
 
 
 class CycleExcpetion(TypingException):
+    """Exception raised when a type is its own parent (type cycle)"""
 
-    def __init__(self, first_type, final_name):
+    def __init__(self, first_type: "DefineEntity", final_name: str) -> None:
         super(CycleExcpetion, self).__init__(first_type, None)
-        self.types = []
+        self.types = []  # type: List[DefineEntity]
         self.complete = False
         self.final_name = final_name
 
-    def add(self, element):
+    def add(self, element: "DefineEntity") -> None:
+        """Collect parent entities while traveling up the stack"""
         if(self.complete):
             return
         if element.get_full_name() == self.final_name:
@@ -649,7 +666,26 @@ def __init__(self, stmt: "Statement", value: object, location: Location, newvalu
         RuntimeException.__init__(self, stmt, msg)
 
 
+class ModifiedAfterFreezeException(RuntimeException):
+
+    def __init__(self,
+                 rv: "DelayedResultVariable",
+                 instance: "Entity",
+                 attribute: "Attribute",
+                 value: object,
+                 location: Location,
+                 reverse: bool) -> None:
+        RuntimeException.__init__(self, None, "List modified after freeze")
+        self.instance = instance
+        self.attribute = attribute
+        self.value = value
+        self.location = location
+        self.resultvariable = rv
+        self.reverse = reverse
+
+
 class DuplicateException(TypingException):
+    """ Exception raise when something is defined twice """
 
     def __init__(self, stmt: Locatable, other: Locatable, msg: str) -> None:
         TypingException.__init__(self, stmt, msg)
@@ -665,6 +701,7 @@ class CompilerError(Exception):
 
 
 class MultiException(CompilerException):
+    """A single exception collecting multiple CompilerExceptions"""
 
     def __init__(self, others: List[CompilerException]) -> None:
         CompilerException.__init__(self, "")

src/inmanta/ast/statements/generator.py

@@ -203,6 +203,9 @@ def __init__(self,
         self._indirect_attributes = {}  # type: Dict[str,ExpressionStatement]
         self._use_default = set()  # type: Set[str]
 
+    def pretty_print(self) -> str:
+        return "%s(%s)" % (self.class_type, ",".join(("%s=%s" % (k, v.pretty_print()) for k, v in self.attributes.items())))
+
     def normalize(self) -> None:
         mytype = self.namespace.get_type(self.class_type)