init

.venv/lib/python3.8/site-packages/jedi/inference/__init__.py

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+"""
+Type inference of Python code in |jedi| is based on three assumptions:
+
+* The code uses as least side effects as possible. Jedi understands certain
+  list/tuple/set modifications, but there's no guarantee that Jedi detects
+  everything (list.append in different modules for example).
+* No magic is being used:
+
+  - metaclasses
+  - ``setattr()`` / ``__import__()``
+  - writing to ``globals()``, ``locals()``, ``object.__dict__``
+* The programmer is not a total dick, e.g. like `this
+  <https://github.com/davidhalter/jedi/issues/24>`_ :-)
+
+The actual algorithm is based on a principle I call lazy type inference.  That
+said, the typical entry point for static analysis is calling
+``infer_expr_stmt``. There's separate logic for autocompletion in the API, the
+inference_state is all about inferring an expression.
+
+TODO this paragraph is not what jedi does anymore, it's similar, but not the
+same.
+
+Now you need to understand what follows after ``infer_expr_stmt``. Let's
+make an example::
+
+    import datetime
+    datetime.date.toda# <-- cursor here
+
+First of all, this module doesn't care about completion. It really just cares
+about ``datetime.date``. At the end of the procedure ``infer_expr_stmt`` will
+return the ``date`` class.
+
+To *visualize* this (simplified):
+
+- ``InferenceState.infer_expr_stmt`` doesn't do much, because there's no assignment.
+- ``Context.infer_node`` cares for resolving the dotted path
+- ``InferenceState.find_types`` searches for global definitions of datetime, which
+  it finds in the definition of an import, by scanning the syntax tree.
+- Using the import logic, the datetime module is found.
+- Now ``find_types`` is called again by ``infer_node`` to find ``date``
+  inside the datetime module.
+
+Now what would happen if we wanted ``datetime.date.foo.bar``? Two more
+calls to ``find_types``. However the second call would be ignored, because the
+first one would return nothing (there's no foo attribute in ``date``).
+
+What if the import would contain another ``ExprStmt`` like this::
+
+    from foo import bar
+    Date = bar.baz
+
+Well... You get it. Just another ``infer_expr_stmt`` recursion. It's really
+easy. Python can obviously get way more complicated then this. To understand
+tuple assignments, list comprehensions and everything else, a lot more code had
+to be written.
+
+Jedi has been tested very well, so you can just start modifying code. It's best
+to write your own test first for your "new" feature. Don't be scared of
+breaking stuff. As long as the tests pass, you're most likely to be fine.
+
+I need to mention now that lazy type inference is really good because it
+only *inferes* what needs to be *inferred*. All the statements and modules
+that are not used are just being ignored.
+"""
+import parso
+from jedi.file_io import FileIO
+
+from jedi import debug
+from jedi import settings
+from jedi.inference import imports
+from jedi.inference import recursion
+from jedi.inference.cache import inference_state_function_cache
+from jedi.inference import helpers
+from jedi.inference.names import TreeNameDefinition
+from jedi.inference.base_value import ContextualizedNode, \
+    ValueSet, iterate_values
+from jedi.inference.value import ClassValue, FunctionValue
+from jedi.inference.syntax_tree import infer_expr_stmt, \
+    check_tuple_assignments, tree_name_to_values
+from jedi.inference.imports import follow_error_node_imports_if_possible
+from jedi.plugins import plugin_manager
+
+
+class InferenceState:
+    def __init__(self, project, environment=None, script_path=None):
+        if environment is None:
+            environment = project.get_environment()
+        self.environment = environment
+        self.script_path = script_path
+        self.compiled_subprocess = environment.get_inference_state_subprocess(self)
+        self.grammar = environment.get_grammar()
+
+        self.latest_grammar = parso.load_grammar(version='3.7')
+        self.memoize_cache = {}  # for memoize decorators
+        self.module_cache = imports.ModuleCache()  # does the job of `sys.modules`.
+        self.stub_module_cache = {}  # Dict[Tuple[str, ...], Optional[ModuleValue]]
+        self.compiled_cache = {}  # see `inference.compiled.create()`
+        self.inferred_element_counts = {}
+        self.mixed_cache = {}  # see `inference.compiled.mixed._create()`
+        self.analysis = []
+        self.dynamic_params_depth = 0
+        self.is_analysis = False
+        self.project = project
+        self.access_cache = {}
+        self.allow_descriptor_getattr = False
+        self.flow_analysis_enabled = True
+
+        self.reset_recursion_limitations()
+
+    def import_module(self, import_names, sys_path=None, prefer_stubs=True):
+        return imports.import_module_by_names(
+            self, import_names, sys_path, prefer_stubs=prefer_stubs)
+
+    @staticmethod
+    @plugin_manager.decorate()
+    def execute(value, arguments):
+        debug.dbg('execute: %s %s', value, arguments)
+        with debug.increase_indent_cm():
+            value_set = value.py__call__(arguments=arguments)
+        debug.dbg('execute result: %s in %s', value_set, value)
+        return value_set
+
+    # mypy doesn't suppport decorated propeties (https://github.com/python/mypy/issues/1362)
+    @property  # type: ignore[misc]
+    @inference_state_function_cache()
+    def builtins_module(self):
+        module_name = 'builtins'
+        builtins_module, = self.import_module((module_name,), sys_path=())
+        return builtins_module
+
+    @property  # type: ignore[misc]
+    @inference_state_function_cache()
+    def typing_module(self):
+        typing_module, = self.import_module(('typing',))
+        return typing_module
+
+    def reset_recursion_limitations(self):
+        self.recursion_detector = recursion.RecursionDetector()
+        self.execution_recursion_detector = recursion.ExecutionRecursionDetector(self)
+
+    def get_sys_path(self, **kwargs):
+        """Convenience function"""
+        return self.project._get_sys_path(self, **kwargs)
+
+    def infer(self, context, name):
+        def_ = name.get_definition(import_name_always=True)
+        if def_ is not None:
+            type_ = def_.type
+            is_classdef = type_ == 'classdef'
+            if is_classdef or type_ == 'funcdef':
+                if is_classdef:
+                    c = ClassValue(self, context, name.parent)
+                else:
+                    c = FunctionValue.from_context(context, name.parent)
+                return ValueSet([c])
+
+            if type_ == 'expr_stmt':
+                is_simple_name = name.parent.type not in ('power', 'trailer')
+                if is_simple_name:
+                    return infer_expr_stmt(context, def_, name)
+            if type_ == 'for_stmt':
+                container_types = context.infer_node(def_.children[3])
+                cn = ContextualizedNode(context, def_.children[3])
+                for_types = iterate_values(container_types, cn)
+                n = TreeNameDefinition(context, name)
+                return check_tuple_assignments(n, for_types)
+            if type_ in ('import_from', 'import_name'):
+                return imports.infer_import(context, name)
+            if type_ == 'with_stmt':
+                return tree_name_to_values(self, context, name)
+            elif type_ == 'param':
+                return context.py__getattribute__(name.value, position=name.end_pos)
+            elif type_ == 'namedexpr_test':
+                return context.infer_node(def_)
+        else:
+            result = follow_error_node_imports_if_possible(context, name)
+            if result is not None:
+                return result
+
+        return helpers.infer_call_of_leaf(context, name)
+
+    def parse_and_get_code(self, code=None, path=None,
+                           use_latest_grammar=False, file_io=None, **kwargs):
+        if code is None:
+            if file_io is None:
+                file_io = FileIO(path)
+            code = file_io.read()
+        # We cannot just use parso, because it doesn't use errors='replace'.
+        code = parso.python_bytes_to_unicode(code, encoding='utf-8', errors='replace')
+
+        if len(code) > settings._cropped_file_size:
+            code = code[:settings._cropped_file_size]
+
+        grammar = self.latest_grammar if use_latest_grammar else self.grammar
+        return grammar.parse(code=code, path=path, file_io=file_io, **kwargs), code
+
+    def parse(self, *args, **kwargs):
+        return self.parse_and_get_code(*args, **kwargs)[0]