| # Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0 |
| # For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt |
| |
| """Code parsing for coverage.py.""" |
| |
| import ast |
| import collections |
| import os |
| import re |
| import token |
| import tokenize |
| |
| from coverage import env |
| from coverage.backward import range # pylint: disable=redefined-builtin |
| from coverage.backward import bytes_to_ints, string_class |
| from coverage.bytecode import CodeObjects |
| from coverage.debug import short_stack |
| from coverage.misc import contract, join_regex, new_contract, nice_pair, one_of |
| from coverage.misc import NoSource, IncapablePython, NotPython |
| from coverage.phystokens import compile_unicode, generate_tokens, neuter_encoding_declaration |
| |
| |
| class PythonParser(object): |
| """Parse code to find executable lines, excluded lines, etc. |
| |
| This information is all based on static analysis: no code execution is |
| involved. |
| |
| """ |
| @contract(text='unicode|None') |
| def __init__(self, text=None, filename=None, exclude=None): |
| """ |
| Source can be provided as `text`, the text itself, or `filename`, from |
| which the text will be read. Excluded lines are those that match |
| `exclude`, a regex. |
| |
| """ |
| assert text or filename, "PythonParser needs either text or filename" |
| self.filename = filename or "<code>" |
| self.text = text |
| if not self.text: |
| from coverage.python import get_python_source |
| try: |
| self.text = get_python_source(self.filename) |
| except IOError as err: |
| raise NoSource( |
| "No source for code: '%s': %s" % (self.filename, err) |
| ) |
| |
| self.exclude = exclude |
| |
| # The text lines of the parsed code. |
| self.lines = self.text.split('\n') |
| |
| # The normalized line numbers of the statements in the code. Exclusions |
| # are taken into account, and statements are adjusted to their first |
| # lines. |
| self.statements = set() |
| |
| # The normalized line numbers of the excluded lines in the code, |
| # adjusted to their first lines. |
| self.excluded = set() |
| |
| # The raw_* attributes are only used in this class, and in |
| # lab/parser.py to show how this class is working. |
| |
| # The line numbers that start statements, as reported by the line |
| # number table in the bytecode. |
| self.raw_statements = set() |
| |
| # The raw line numbers of excluded lines of code, as marked by pragmas. |
| self.raw_excluded = set() |
| |
| # The line numbers of class and function definitions. |
| self.raw_classdefs = set() |
| |
| # The line numbers of docstring lines. |
| self.raw_docstrings = set() |
| |
| # Internal detail, used by lab/parser.py. |
| self.show_tokens = False |
| |
| # A dict mapping line numbers to lexical statement starts for |
| # multi-line statements. |
| self._multiline = {} |
| |
| # Lazily-created ByteParser, arc data, and missing arc descriptions. |
| self._byte_parser = None |
| self._all_arcs = None |
| self._missing_arc_fragments = None |
| |
| @property |
| def byte_parser(self): |
| """Create a ByteParser on demand.""" |
| if not self._byte_parser: |
| self._byte_parser = ByteParser(self.text, filename=self.filename) |
| return self._byte_parser |
| |
| def lines_matching(self, *regexes): |
| """Find the lines matching one of a list of regexes. |
| |
| Returns a set of line numbers, the lines that contain a match for one |
| of the regexes in `regexes`. The entire line needn't match, just a |
| part of it. |
| |
| """ |
| combined = join_regex(regexes) |
| if env.PY2: |
| # pylint: disable=redefined-variable-type |
| combined = combined.decode("utf8") |
| regex_c = re.compile(combined) |
| matches = set() |
| for i, ltext in enumerate(self.lines, start=1): |
| if regex_c.search(ltext): |
| matches.add(i) |
| return matches |
| |
| def _raw_parse(self): |
| """Parse the source to find the interesting facts about its lines. |
| |
| A handful of attributes are updated. |
| |
| """ |
| # Find lines which match an exclusion pattern. |
| if self.exclude: |
| self.raw_excluded = self.lines_matching(self.exclude) |
| |
| # Tokenize, to find excluded suites, to find docstrings, and to find |
| # multi-line statements. |
| indent = 0 |
| exclude_indent = 0 |
| excluding = False |
| excluding_decorators = False |
| prev_toktype = token.INDENT |
| first_line = None |
| empty = True |
| first_on_line = True |
| |
| tokgen = generate_tokens(self.text) |
| for toktype, ttext, (slineno, _), (elineno, _), ltext in tokgen: |
| if self.show_tokens: # pragma: not covered |
| print("%10s %5s %-20r %r" % ( |
| tokenize.tok_name.get(toktype, toktype), |
| nice_pair((slineno, elineno)), ttext, ltext |
| )) |
| if toktype == token.INDENT: |
| indent += 1 |
| elif toktype == token.DEDENT: |
| indent -= 1 |
| elif toktype == token.NAME: |
| if ttext == 'class': |
| # Class definitions look like branches in the bytecode, so |
| # we need to exclude them. The simplest way is to note the |
| # lines with the 'class' keyword. |
| self.raw_classdefs.add(slineno) |
| elif toktype == token.OP: |
| if ttext == ':': |
| should_exclude = (elineno in self.raw_excluded) or excluding_decorators |
| if not excluding and should_exclude: |
| # Start excluding a suite. We trigger off of the colon |
| # token so that the #pragma comment will be recognized on |
| # the same line as the colon. |
| self.raw_excluded.add(elineno) |
| exclude_indent = indent |
| excluding = True |
| excluding_decorators = False |
| elif ttext == '@' and first_on_line: |
| # A decorator. |
| if elineno in self.raw_excluded: |
| excluding_decorators = True |
| if excluding_decorators: |
| self.raw_excluded.add(elineno) |
| elif toktype == token.STRING and prev_toktype == token.INDENT: |
| # Strings that are first on an indented line are docstrings. |
| # (a trick from trace.py in the stdlib.) This works for |
| # 99.9999% of cases. For the rest (!) see: |
| # http://stackoverflow.com/questions/1769332/x/1769794#1769794 |
| self.raw_docstrings.update(range(slineno, elineno+1)) |
| elif toktype == token.NEWLINE: |
| if first_line is not None and elineno != first_line: |
| # We're at the end of a line, and we've ended on a |
| # different line than the first line of the statement, |
| # so record a multi-line range. |
| for l in range(first_line, elineno+1): |
| self._multiline[l] = first_line |
| first_line = None |
| first_on_line = True |
| |
| if ttext.strip() and toktype != tokenize.COMMENT: |
| # A non-whitespace token. |
| empty = False |
| if first_line is None: |
| # The token is not whitespace, and is the first in a |
| # statement. |
| first_line = slineno |
| # Check whether to end an excluded suite. |
| if excluding and indent <= exclude_indent: |
| excluding = False |
| if excluding: |
| self.raw_excluded.add(elineno) |
| first_on_line = False |
| |
| prev_toktype = toktype |
| |
| # Find the starts of the executable statements. |
| if not empty: |
| self.raw_statements.update(self.byte_parser._find_statements()) |
| |
| def first_line(self, line): |
| """Return the first line number of the statement including `line`.""" |
| return self._multiline.get(line, line) |
| |
| def first_lines(self, lines): |
| """Map the line numbers in `lines` to the correct first line of the |
| statement. |
| |
| Returns a set of the first lines. |
| |
| """ |
| return set(self.first_line(l) for l in lines) |
| |
| def translate_lines(self, lines): |
| """Implement `FileReporter.translate_lines`.""" |
| return self.first_lines(lines) |
| |
| def translate_arcs(self, arcs): |
| """Implement `FileReporter.translate_arcs`.""" |
| return [(self.first_line(a), self.first_line(b)) for (a, b) in arcs] |
| |
| def parse_source(self): |
| """Parse source text to find executable lines, excluded lines, etc. |
| |
| Sets the .excluded and .statements attributes, normalized to the first |
| line of multi-line statements. |
| |
| """ |
| try: |
| self._raw_parse() |
| except (tokenize.TokenError, IndentationError) as err: |
| if hasattr(err, "lineno"): |
| lineno = err.lineno # IndentationError |
| else: |
| lineno = err.args[1][0] # TokenError |
| raise NotPython( |
| u"Couldn't parse '%s' as Python source: '%s' at line %d" % ( |
| self.filename, err.args[0], lineno |
| ) |
| ) |
| |
| self.excluded = self.first_lines(self.raw_excluded) |
| |
| ignore = self.excluded | self.raw_docstrings |
| starts = self.raw_statements - ignore |
| self.statements = self.first_lines(starts) - ignore |
| |
| def arcs(self): |
| """Get information about the arcs available in the code. |
| |
| Returns a set of line number pairs. Line numbers have been normalized |
| to the first line of multi-line statements. |
| |
| """ |
| if self._all_arcs is None: |
| self._analyze_ast() |
| return self._all_arcs |
| |
| def _analyze_ast(self): |
| """Run the AstArcAnalyzer and save its results. |
| |
| `_all_arcs` is the set of arcs in the code. |
| |
| """ |
| aaa = AstArcAnalyzer(self.text, self.raw_statements, self._multiline) |
| aaa.analyze() |
| |
| self._all_arcs = set() |
| for l1, l2 in aaa.arcs: |
| fl1 = self.first_line(l1) |
| fl2 = self.first_line(l2) |
| if fl1 != fl2: |
| self._all_arcs.add((fl1, fl2)) |
| |
| self._missing_arc_fragments = aaa.missing_arc_fragments |
| |
| def exit_counts(self): |
| """Get a count of exits from that each line. |
| |
| Excluded lines are excluded. |
| |
| """ |
| exit_counts = collections.defaultdict(int) |
| for l1, l2 in self.arcs(): |
| if l1 < 0: |
| # Don't ever report -1 as a line number |
| continue |
| if l1 in self.excluded: |
| # Don't report excluded lines as line numbers. |
| continue |
| if l2 in self.excluded: |
| # Arcs to excluded lines shouldn't count. |
| continue |
| exit_counts[l1] += 1 |
| |
| # Class definitions have one extra exit, so remove one for each: |
| for l in self.raw_classdefs: |
| # Ensure key is there: class definitions can include excluded lines. |
| if l in exit_counts: |
| exit_counts[l] -= 1 |
| |
| return exit_counts |
| |
| def missing_arc_description(self, start, end, executed_arcs=None): |
| """Provide an English sentence describing a missing arc.""" |
| if self._missing_arc_fragments is None: |
| self._analyze_ast() |
| |
| actual_start = start |
| |
| if ( |
| executed_arcs and |
| end < 0 and end == -start and |
| (end, start) not in executed_arcs and |
| (end, start) in self._missing_arc_fragments |
| ): |
| # It's a one-line callable, and we never even started it, |
| # and we have a message about not starting it. |
| start, end = end, start |
| |
| fragment_pairs = self._missing_arc_fragments.get((start, end), [(None, None)]) |
| |
| msgs = [] |
| for fragment_pair in fragment_pairs: |
| smsg, emsg = fragment_pair |
| |
| if emsg is None: |
| if end < 0: |
| # Hmm, maybe we have a one-line callable, let's check. |
| if (-end, end) in self._missing_arc_fragments: |
| return self.missing_arc_description(-end, end) |
| emsg = "didn't jump to the function exit" |
| else: |
| emsg = "didn't jump to line {lineno}" |
| emsg = emsg.format(lineno=end) |
| |
| msg = "line {start} {emsg}".format(start=actual_start, emsg=emsg) |
| if smsg is not None: |
| msg += ", because {smsg}".format(smsg=smsg.format(lineno=actual_start)) |
| |
| msgs.append(msg) |
| |
| return " or ".join(msgs) |
| |
| |
| class ByteParser(object): |
| """Parse bytecode to understand the structure of code.""" |
| |
| @contract(text='unicode') |
| def __init__(self, text, code=None, filename=None): |
| self.text = text |
| if code: |
| self.code = code |
| else: |
| try: |
| self.code = compile_unicode(text, filename, "exec") |
| except SyntaxError as synerr: |
| raise NotPython( |
| u"Couldn't parse '%s' as Python source: '%s' at line %d" % ( |
| filename, synerr.msg, synerr.lineno |
| ) |
| ) |
| |
| # Alternative Python implementations don't always provide all the |
| # attributes on code objects that we need to do the analysis. |
| for attr in ['co_lnotab', 'co_firstlineno']: |
| if not hasattr(self.code, attr): |
| raise IncapablePython( # pragma: only jython |
| "This implementation of Python doesn't support code analysis.\n" |
| "Run coverage.py under another Python for this command." |
| ) |
| |
| def child_parsers(self): |
| """Iterate over all the code objects nested within this one. |
| |
| The iteration includes `self` as its first value. |
| |
| """ |
| children = CodeObjects(self.code) |
| return (ByteParser(self.text, code=c) for c in children) |
| |
| def _bytes_lines(self): |
| """Map byte offsets to line numbers in `code`. |
| |
| Uses co_lnotab described in Python/compile.c to map byte offsets to |
| line numbers. Produces a sequence: (b0, l0), (b1, l1), ... |
| |
| Only byte offsets that correspond to line numbers are included in the |
| results. |
| |
| """ |
| # Adapted from dis.py in the standard library. |
| byte_increments = bytes_to_ints(self.code.co_lnotab[0::2]) |
| line_increments = bytes_to_ints(self.code.co_lnotab[1::2]) |
| |
| last_line_num = None |
| line_num = self.code.co_firstlineno |
| byte_num = 0 |
| for byte_incr, line_incr in zip(byte_increments, line_increments): |
| if byte_incr: |
| if line_num != last_line_num: |
| yield (byte_num, line_num) |
| last_line_num = line_num |
| byte_num += byte_incr |
| line_num += line_incr |
| if line_num != last_line_num: |
| yield (byte_num, line_num) |
| |
| def _find_statements(self): |
| """Find the statements in `self.code`. |
| |
| Produce a sequence of line numbers that start statements. Recurses |
| into all code objects reachable from `self.code`. |
| |
| """ |
| for bp in self.child_parsers(): |
| # Get all of the lineno information from this code. |
| for _, l in bp._bytes_lines(): |
| yield l |
| |
| |
| # |
| # AST analysis |
| # |
| |
| class LoopBlock(object): |
| """A block on the block stack representing a `for` or `while` loop.""" |
| @contract(start=int) |
| def __init__(self, start): |
| # The line number where the loop starts. |
| self.start = start |
| # A set of ArcStarts, the arcs from break statements exiting this loop. |
| self.break_exits = set() |
| |
| |
| class FunctionBlock(object): |
| """A block on the block stack representing a function definition.""" |
| @contract(start=int, name=str) |
| def __init__(self, start, name): |
| # The line number where the function starts. |
| self.start = start |
| # The name of the function. |
| self.name = name |
| |
| |
| class TryBlock(object): |
| """A block on the block stack representing a `try` block.""" |
| @contract(handler_start='int|None', final_start='int|None') |
| def __init__(self, handler_start, final_start): |
| # The line number of the first "except" handler, if any. |
| self.handler_start = handler_start |
| # The line number of the "finally:" clause, if any. |
| self.final_start = final_start |
| |
| # The ArcStarts for breaks/continues/returns/raises inside the "try:" |
| # that need to route through the "finally:" clause. |
| self.break_from = set() |
| self.continue_from = set() |
| self.return_from = set() |
| self.raise_from = set() |
| |
| |
| class ArcStart(collections.namedtuple("Arc", "lineno, cause")): |
| """The information needed to start an arc. |
| |
| `lineno` is the line number the arc starts from. |
| |
| `cause` is an English text fragment used as the `startmsg` for |
| AstArcAnalyzer.missing_arc_fragments. It will be used to describe why an |
| arc wasn't executed, so should fit well into a sentence of the form, |
| "Line 17 didn't run because {cause}." The fragment can include "{lineno}" |
| to have `lineno` interpolated into it. |
| |
| """ |
| def __new__(cls, lineno, cause=None): |
| return super(ArcStart, cls).__new__(cls, lineno, cause) |
| |
| |
| # Define contract words that PyContract doesn't have. |
| # ArcStarts is for a list or set of ArcStart's. |
| new_contract('ArcStarts', lambda seq: all(isinstance(x, ArcStart) for x in seq)) |
| |
| |
| # Turn on AST dumps with an environment variable. |
| AST_DUMP = bool(int(os.environ.get("COVERAGE_AST_DUMP", 0))) |
| |
| class NodeList(object): |
| """A synthetic fictitious node, containing a sequence of nodes. |
| |
| This is used when collapsing optimized if-statements, to represent the |
| unconditional execution of one of the clauses. |
| |
| """ |
| def __init__(self, body): |
| self.body = body |
| self.lineno = body[0].lineno |
| |
| |
| class AstArcAnalyzer(object): |
| """Analyze source text with an AST to find executable code paths.""" |
| |
| @contract(text='unicode', statements=set) |
| def __init__(self, text, statements, multiline): |
| self.root_node = ast.parse(neuter_encoding_declaration(text)) |
| # TODO: I think this is happening in too many places. |
| self.statements = set(multiline.get(l, l) for l in statements) |
| self.multiline = multiline |
| |
| if AST_DUMP: # pragma: debugging |
| # Dump the AST so that failing tests have helpful output. |
| print("Statements: {0}".format(self.statements)) |
| print("Multiline map: {0}".format(self.multiline)) |
| ast_dump(self.root_node) |
| |
| self.arcs = set() |
| |
| # A map from arc pairs to a list of pairs of sentence fragments: |
| # { (start, end): [(startmsg, endmsg), ...], } |
| # |
| # For an arc from line 17, they should be usable like: |
| # "Line 17 {endmsg}, because {startmsg}" |
| self.missing_arc_fragments = collections.defaultdict(list) |
| self.block_stack = [] |
| |
| self.debug = bool(int(os.environ.get("COVERAGE_TRACK_ARCS", 0))) |
| |
| def analyze(self): |
| """Examine the AST tree from `root_node` to determine possible arcs. |
| |
| This sets the `arcs` attribute to be a set of (from, to) line number |
| pairs. |
| |
| """ |
| for node in ast.walk(self.root_node): |
| node_name = node.__class__.__name__ |
| code_object_handler = getattr(self, "_code_object__" + node_name, None) |
| if code_object_handler is not None: |
| code_object_handler(node) |
| |
| def add_arc(self, start, end, smsg=None, emsg=None): |
| """Add an arc, including message fragments to use if it is missing.""" |
| if self.debug: |
| print("\nAdding arc: ({}, {}): {!r}, {!r}".format(start, end, smsg, emsg)) |
| print(short_stack(limit=6)) |
| self.arcs.add((start, end)) |
| |
| if smsg is not None or emsg is not None: |
| self.missing_arc_fragments[(start, end)].append((smsg, emsg)) |
| |
| def nearest_blocks(self): |
| """Yield the blocks in nearest-to-farthest order.""" |
| return reversed(self.block_stack) |
| |
| @contract(returns=int) |
| def line_for_node(self, node): |
| """What is the right line number to use for this node? |
| |
| This dispatches to _line__Node functions where needed. |
| |
| """ |
| node_name = node.__class__.__name__ |
| handler = getattr(self, "_line__" + node_name, None) |
| if handler is not None: |
| return handler(node) |
| else: |
| return node.lineno |
| |
| def _line__Assign(self, node): |
| return self.line_for_node(node.value) |
| |
| def _line__Dict(self, node): |
| # Python 3.5 changed how dict literals are made. |
| if env.PYVERSION >= (3, 5) and node.keys: |
| if node.keys[0] is not None: |
| return node.keys[0].lineno |
| else: |
| # Unpacked dict literals `{**{'a':1}}` have None as the key, |
| # use the value in that case. |
| return node.values[0].lineno |
| else: |
| return node.lineno |
| |
| def _line__List(self, node): |
| if node.elts: |
| return self.line_for_node(node.elts[0]) |
| else: |
| return node.lineno |
| |
| def _line__Module(self, node): |
| if node.body: |
| return self.line_for_node(node.body[0]) |
| else: |
| # Empty modules have no line number, they always start at 1. |
| return 1 |
| |
| # The node types that just flow to the next node with no complications. |
| OK_TO_DEFAULT = set([ |
| "Assign", "Assert", "AugAssign", "Delete", "Exec", "Expr", "Global", |
| "Import", "ImportFrom", "Nonlocal", "Pass", "Print", |
| ]) |
| |
| @contract(returns='ArcStarts') |
| def add_arcs(self, node): |
| """Add the arcs for `node`. |
| |
| Return a set of ArcStarts, exits from this node to the next. Because a |
| node represents an entire sub-tree (including its children), the exits |
| from a node can be arbitrarily complex:: |
| |
| if something(1): |
| if other(2): |
| doit(3) |
| else: |
| doit(5) |
| |
| There are two exits from line 1: they start at line 3 and line 5. |
| |
| """ |
| node_name = node.__class__.__name__ |
| handler = getattr(self, "_handle__" + node_name, None) |
| if handler is not None: |
| return handler(node) |
| else: |
| # No handler: either it's something that's ok to default (a simple |
| # statement), or it's something we overlooked. Change this 0 to 1 |
| # to see if it's overlooked. |
| if 0: |
| if node_name not in self.OK_TO_DEFAULT: |
| print("*** Unhandled: {0}".format(node)) |
| |
| # Default for simple statements: one exit from this node. |
| return set([ArcStart(self.line_for_node(node))]) |
| |
| @one_of("from_start, prev_starts") |
| @contract(returns='ArcStarts') |
| def add_body_arcs(self, body, from_start=None, prev_starts=None): |
| """Add arcs for the body of a compound statement. |
| |
| `body` is the body node. `from_start` is a single `ArcStart` that can |
| be the previous line in flow before this body. `prev_starts` is a set |
| of ArcStarts that can be the previous line. Only one of them should be |
| given. |
| |
| Returns a set of ArcStarts, the exits from this body. |
| |
| """ |
| if prev_starts is None: |
| prev_starts = set([from_start]) |
| for body_node in body: |
| lineno = self.line_for_node(body_node) |
| first_line = self.multiline.get(lineno, lineno) |
| if first_line not in self.statements: |
| body_node = self.find_non_missing_node(body_node) |
| if body_node is None: |
| continue |
| lineno = self.line_for_node(body_node) |
| for prev_start in prev_starts: |
| self.add_arc(prev_start.lineno, lineno, prev_start.cause) |
| prev_starts = self.add_arcs(body_node) |
| return prev_starts |
| |
| def find_non_missing_node(self, node): |
| """Search `node` looking for a child that has not been optimized away. |
| |
| This might return the node you started with, or it will work recursively |
| to find a child node in self.statements. |
| |
| Returns a node, or None if none of the node remains. |
| |
| """ |
| # This repeats work just done in add_body_arcs, but this duplication |
| # means we can avoid a function call in the 99.9999% case of not |
| # optimizing away statements. |
| lineno = self.line_for_node(node) |
| first_line = self.multiline.get(lineno, lineno) |
| if first_line in self.statements: |
| return node |
| |
| missing_fn = getattr(self, "_missing__" + node.__class__.__name__, None) |
| if missing_fn: |
| node = missing_fn(node) |
| else: |
| node = None |
| return node |
| |
| def _missing__If(self, node): |
| # If the if-node is missing, then one of its children might still be |
| # here, but not both. So return the first of the two that isn't missing. |
| # Use a NodeList to hold the clauses as a single node. |
| non_missing = self.find_non_missing_node(NodeList(node.body)) |
| if non_missing: |
| return non_missing |
| if node.orelse: |
| return self.find_non_missing_node(NodeList(node.orelse)) |
| return None |
| |
| def _missing__NodeList(self, node): |
| # A NodeList might be a mixture of missing and present nodes. Find the |
| # ones that are present. |
| non_missing_children = [] |
| for child in node.body: |
| child = self.find_non_missing_node(child) |
| if child is not None: |
| non_missing_children.append(child) |
| |
| # Return the simplest representation of the present children. |
| if not non_missing_children: |
| return None |
| if len(non_missing_children) == 1: |
| return non_missing_children[0] |
| return NodeList(non_missing_children) |
| |
| def is_constant_expr(self, node): |
| """Is this a compile-time constant?""" |
| node_name = node.__class__.__name__ |
| if node_name in ["NameConstant", "Num"]: |
| return "Num" |
| elif node_name == "Name": |
| if node.id in ["True", "False", "None", "__debug__"]: |
| return "Name" |
| return None |
| |
| # In the fullness of time, these might be good tests to write: |
| # while EXPR: |
| # while False: |
| # listcomps hidden deep in other expressions |
| # listcomps hidden in lists: x = [[i for i in range(10)]] |
| # nested function definitions |
| |
| |
| # Exit processing: process_*_exits |
| # |
| # These functions process the four kinds of jump exits: break, continue, |
| # raise, and return. To figure out where an exit goes, we have to look at |
| # the block stack context. For example, a break will jump to the nearest |
| # enclosing loop block, or the nearest enclosing finally block, whichever |
| # is nearer. |
| |
| @contract(exits='ArcStarts') |
| def process_break_exits(self, exits): |
| """Add arcs due to jumps from `exits` being breaks.""" |
| for block in self.nearest_blocks(): |
| if isinstance(block, LoopBlock): |
| block.break_exits.update(exits) |
| break |
| elif isinstance(block, TryBlock) and block.final_start is not None: |
| block.break_from.update(exits) |
| break |
| |
| @contract(exits='ArcStarts') |
| def process_continue_exits(self, exits): |
| """Add arcs due to jumps from `exits` being continues.""" |
| for block in self.nearest_blocks(): |
| if isinstance(block, LoopBlock): |
| for xit in exits: |
| self.add_arc(xit.lineno, block.start, xit.cause) |
| break |
| elif isinstance(block, TryBlock) and block.final_start is not None: |
| block.continue_from.update(exits) |
| break |
| |
| @contract(exits='ArcStarts') |
| def process_raise_exits(self, exits): |
| """Add arcs due to jumps from `exits` being raises.""" |
| for block in self.nearest_blocks(): |
| if isinstance(block, TryBlock): |
| if block.handler_start is not None: |
| for xit in exits: |
| self.add_arc(xit.lineno, block.handler_start, xit.cause) |
| break |
| elif block.final_start is not None: |
| block.raise_from.update(exits) |
| break |
| elif isinstance(block, FunctionBlock): |
| for xit in exits: |
| self.add_arc( |
| xit.lineno, -block.start, xit.cause, |
| "didn't except from function '{0}'".format(block.name), |
| ) |
| break |
| |
| @contract(exits='ArcStarts') |
| def process_return_exits(self, exits): |
| """Add arcs due to jumps from `exits` being returns.""" |
| for block in self.nearest_blocks(): |
| if isinstance(block, TryBlock) and block.final_start is not None: |
| block.return_from.update(exits) |
| break |
| elif isinstance(block, FunctionBlock): |
| for xit in exits: |
| self.add_arc( |
| xit.lineno, -block.start, xit.cause, |
| "didn't return from function '{0}'".format(block.name), |
| ) |
| break |
| |
| |
| # Handlers: _handle__* |
| # |
| # Each handler deals with a specific AST node type, dispatched from |
| # add_arcs. Each deals with a particular kind of node type, and returns |
| # the set of exits from that node. These functions mirror the Python |
| # semantics of each syntactic construct. See the docstring for add_arcs to |
| # understand the concept of exits from a node. |
| |
| @contract(returns='ArcStarts') |
| def _handle__Break(self, node): |
| here = self.line_for_node(node) |
| break_start = ArcStart(here, cause="the break on line {lineno} wasn't executed") |
| self.process_break_exits([break_start]) |
| return set() |
| |
| @contract(returns='ArcStarts') |
| def _handle_decorated(self, node): |
| """Add arcs for things that can be decorated (classes and functions).""" |
| last = self.line_for_node(node) |
| if node.decorator_list: |
| for dec_node in node.decorator_list: |
| dec_start = self.line_for_node(dec_node) |
| if dec_start != last: |
| self.add_arc(last, dec_start) |
| last = dec_start |
| # The definition line may have been missed, but we should have it |
| # in `self.statements`. For some constructs, `line_for_node` is |
| # not what we'd think of as the first line in the statement, so map |
| # it to the first one. |
| body_start = self.line_for_node(node.body[0]) |
| body_start = self.multiline.get(body_start, body_start) |
| for lineno in range(last+1, body_start): |
| if lineno in self.statements: |
| self.add_arc(last, lineno) |
| last = lineno |
| # The body is handled in collect_arcs. |
| return set([ArcStart(last)]) |
| |
| _handle__ClassDef = _handle_decorated |
| |
| @contract(returns='ArcStarts') |
| def _handle__Continue(self, node): |
| here = self.line_for_node(node) |
| continue_start = ArcStart(here, cause="the continue on line {lineno} wasn't executed") |
| self.process_continue_exits([continue_start]) |
| return set() |
| |
| @contract(returns='ArcStarts') |
| def _handle__For(self, node): |
| start = self.line_for_node(node.iter) |
| self.block_stack.append(LoopBlock(start=start)) |
| from_start = ArcStart(start, cause="the loop on line {lineno} never started") |
| exits = self.add_body_arcs(node.body, from_start=from_start) |
| # Any exit from the body will go back to the top of the loop. |
| for xit in exits: |
| self.add_arc(xit.lineno, start, xit.cause) |
| my_block = self.block_stack.pop() |
| exits = my_block.break_exits |
| from_start = ArcStart(start, cause="the loop on line {lineno} didn't complete") |
| if node.orelse: |
| else_exits = self.add_body_arcs(node.orelse, from_start=from_start) |
| exits |= else_exits |
| else: |
| # No else clause: exit from the for line. |
| exits.add(from_start) |
| return exits |
| |
| _handle__AsyncFor = _handle__For |
| |
| _handle__FunctionDef = _handle_decorated |
| _handle__AsyncFunctionDef = _handle_decorated |
| |
| @contract(returns='ArcStarts') |
| def _handle__If(self, node): |
| start = self.line_for_node(node.test) |
| from_start = ArcStart(start, cause="the condition on line {lineno} was never true") |
| exits = self.add_body_arcs(node.body, from_start=from_start) |
| from_start = ArcStart(start, cause="the condition on line {lineno} was never false") |
| exits |= self.add_body_arcs(node.orelse, from_start=from_start) |
| return exits |
| |
| @contract(returns='ArcStarts') |
| def _handle__NodeList(self, node): |
| start = self.line_for_node(node) |
| exits = self.add_body_arcs(node.body, from_start=ArcStart(start)) |
| return exits |
| |
| @contract(returns='ArcStarts') |
| def _handle__Raise(self, node): |
| here = self.line_for_node(node) |
| raise_start = ArcStart(here, cause="the raise on line {lineno} wasn't executed") |
| self.process_raise_exits([raise_start]) |
| # `raise` statement jumps away, no exits from here. |
| return set() |
| |
| @contract(returns='ArcStarts') |
| def _handle__Return(self, node): |
| here = self.line_for_node(node) |
| return_start = ArcStart(here, cause="the return on line {lineno} wasn't executed") |
| self.process_return_exits([return_start]) |
| # `return` statement jumps away, no exits from here. |
| return set() |
| |
| @contract(returns='ArcStarts') |
| def _handle__Try(self, node): |
| if node.handlers: |
| handler_start = self.line_for_node(node.handlers[0]) |
| else: |
| handler_start = None |
| |
| if node.finalbody: |
| final_start = self.line_for_node(node.finalbody[0]) |
| else: |
| final_start = None |
| |
| try_block = TryBlock(handler_start, final_start) |
| self.block_stack.append(try_block) |
| |
| start = self.line_for_node(node) |
| exits = self.add_body_arcs(node.body, from_start=ArcStart(start)) |
| |
| # We're done with the `try` body, so this block no longer handles |
| # exceptions. We keep the block so the `finally` clause can pick up |
| # flows from the handlers and `else` clause. |
| if node.finalbody: |
| try_block.handler_start = None |
| if node.handlers: |
| # If there are `except` clauses, then raises in the try body |
| # will already jump to them. Start this set over for raises in |
| # `except` and `else`. |
| try_block.raise_from = set([]) |
| else: |
| self.block_stack.pop() |
| |
| handler_exits = set() |
| |
| if node.handlers: |
| last_handler_start = None |
| for handler_node in node.handlers: |
| handler_start = self.line_for_node(handler_node) |
| if last_handler_start is not None: |
| self.add_arc(last_handler_start, handler_start) |
| last_handler_start = handler_start |
| from_cause = "the exception caught by line {lineno} didn't happen" |
| from_start = ArcStart(handler_start, cause=from_cause) |
| handler_exits |= self.add_body_arcs(handler_node.body, from_start=from_start) |
| |
| if node.orelse: |
| exits = self.add_body_arcs(node.orelse, prev_starts=exits) |
| |
| exits |= handler_exits |
| |
| if node.finalbody: |
| self.block_stack.pop() |
| final_from = ( # You can get to the `finally` clause from: |
| exits | # the exits of the body or `else` clause, |
| try_block.break_from | # or a `break`, |
| try_block.continue_from | # or a `continue`, |
| try_block.raise_from | # or a `raise`, |
| try_block.return_from # or a `return`. |
| ) |
| |
| final_exits = self.add_body_arcs(node.finalbody, prev_starts=final_from) |
| |
| if try_block.break_from: |
| self.process_break_exits( |
| self._combine_finally_starts(try_block.break_from, final_exits) |
| ) |
| if try_block.continue_from: |
| self.process_continue_exits( |
| self._combine_finally_starts(try_block.continue_from, final_exits) |
| ) |
| if try_block.raise_from: |
| self.process_raise_exits( |
| self._combine_finally_starts(try_block.raise_from, final_exits) |
| ) |
| if try_block.return_from: |
| self.process_return_exits( |
| self._combine_finally_starts(try_block.return_from, final_exits) |
| ) |
| |
| if exits: |
| # The finally clause's exits are only exits for the try block |
| # as a whole if the try block had some exits to begin with. |
| exits = final_exits |
| |
| return exits |
| |
| @contract(starts='ArcStarts', exits='ArcStarts', returns='ArcStarts') |
| def _combine_finally_starts(self, starts, exits): |
| """Helper for building the cause of `finally` branches. |
| |
| "finally" clauses might not execute their exits, and the causes could |
| be due to a failure to execute any of the exits in the try block. So |
| we use the causes from `starts` as the causes for `exits`. |
| """ |
| causes = [] |
| for start in sorted(starts): |
| if start.cause is not None: |
| causes.append(start.cause.format(lineno=start.lineno)) |
| cause = " or ".join(causes) |
| exits = set(ArcStart(xit.lineno, cause) for xit in exits) |
| return exits |
| |
| @contract(returns='ArcStarts') |
| def _handle__TryExcept(self, node): |
| # Python 2.7 uses separate TryExcept and TryFinally nodes. If we get |
| # TryExcept, it means there was no finally, so fake it, and treat as |
| # a general Try node. |
| node.finalbody = [] |
| return self._handle__Try(node) |
| |
| @contract(returns='ArcStarts') |
| def _handle__TryFinally(self, node): |
| # Python 2.7 uses separate TryExcept and TryFinally nodes. If we get |
| # TryFinally, see if there's a TryExcept nested inside. If so, merge |
| # them. Otherwise, fake fields to complete a Try node. |
| node.handlers = [] |
| node.orelse = [] |
| |
| first = node.body[0] |
| if first.__class__.__name__ == "TryExcept" and node.lineno == first.lineno: |
| assert len(node.body) == 1 |
| node.body = first.body |
| node.handlers = first.handlers |
| node.orelse = first.orelse |
| |
| return self._handle__Try(node) |
| |
| @contract(returns='ArcStarts') |
| def _handle__While(self, node): |
| constant_test = self.is_constant_expr(node.test) |
| start = to_top = self.line_for_node(node.test) |
| if constant_test and (env.PY3 or constant_test == "Num"): |
| to_top = self.line_for_node(node.body[0]) |
| self.block_stack.append(LoopBlock(start=to_top)) |
| from_start = ArcStart(start, cause="the condition on line {lineno} was never true") |
| exits = self.add_body_arcs(node.body, from_start=from_start) |
| for xit in exits: |
| self.add_arc(xit.lineno, to_top, xit.cause) |
| exits = set() |
| my_block = self.block_stack.pop() |
| exits.update(my_block.break_exits) |
| from_start = ArcStart(start, cause="the condition on line {lineno} was never false") |
| if node.orelse: |
| else_exits = self.add_body_arcs(node.orelse, from_start=from_start) |
| exits |= else_exits |
| else: |
| # No `else` clause: you can exit from the start. |
| if not constant_test: |
| exits.add(from_start) |
| return exits |
| |
| @contract(returns='ArcStarts') |
| def _handle__With(self, node): |
| start = self.line_for_node(node) |
| exits = self.add_body_arcs(node.body, from_start=ArcStart(start)) |
| return exits |
| |
| _handle__AsyncWith = _handle__With |
| |
| def _code_object__Module(self, node): |
| start = self.line_for_node(node) |
| if node.body: |
| exits = self.add_body_arcs(node.body, from_start=ArcStart(-start)) |
| for xit in exits: |
| self.add_arc(xit.lineno, -start, xit.cause, "didn't exit the module") |
| else: |
| # Empty module. |
| self.add_arc(-start, start) |
| self.add_arc(start, -start) |
| |
| def _code_object__FunctionDef(self, node): |
| start = self.line_for_node(node) |
| self.block_stack.append(FunctionBlock(start=start, name=node.name)) |
| exits = self.add_body_arcs(node.body, from_start=ArcStart(-start)) |
| self.process_return_exits(exits) |
| self.block_stack.pop() |
| |
| _code_object__AsyncFunctionDef = _code_object__FunctionDef |
| |
| def _code_object__ClassDef(self, node): |
| start = self.line_for_node(node) |
| self.add_arc(-start, start) |
| exits = self.add_body_arcs(node.body, from_start=ArcStart(start)) |
| for xit in exits: |
| self.add_arc( |
| xit.lineno, -start, xit.cause, |
| "didn't exit the body of class '{0}'".format(node.name), |
| ) |
| |
| def _make_oneline_code_method(noun): # pylint: disable=no-self-argument |
| """A function to make methods for online callable _code_object__ methods.""" |
| def _code_object__oneline_callable(self, node): |
| start = self.line_for_node(node) |
| self.add_arc(-start, start, None, "didn't run the {0} on line {1}".format(noun, start)) |
| self.add_arc( |
| start, -start, None, |
| "didn't finish the {0} on line {1}".format(noun, start), |
| ) |
| return _code_object__oneline_callable |
| |
| _code_object__Lambda = _make_oneline_code_method("lambda") |
| _code_object__GeneratorExp = _make_oneline_code_method("generator expression") |
| _code_object__DictComp = _make_oneline_code_method("dictionary comprehension") |
| _code_object__SetComp = _make_oneline_code_method("set comprehension") |
| if env.PY3: |
| _code_object__ListComp = _make_oneline_code_method("list comprehension") |
| |
| |
| if AST_DUMP: # pragma: debugging |
| # Code only used when dumping the AST for debugging. |
| |
| SKIP_DUMP_FIELDS = ["ctx"] |
| |
| def _is_simple_value(value): |
| """Is `value` simple enough to be displayed on a single line?""" |
| return ( |
| value in [None, [], (), {}, set()] or |
| isinstance(value, (string_class, int, float)) |
| ) |
| |
| def ast_dump(node, depth=0): |
| """Dump the AST for `node`. |
| |
| This recursively walks the AST, printing a readable version. |
| |
| """ |
| indent = " " * depth |
| if not isinstance(node, ast.AST): |
| print("{0}<{1} {2!r}>".format(indent, node.__class__.__name__, node)) |
| return |
| |
| lineno = getattr(node, "lineno", None) |
| if lineno is not None: |
| linemark = " @ {0}".format(node.lineno) |
| else: |
| linemark = "" |
| head = "{0}<{1}{2}".format(indent, node.__class__.__name__, linemark) |
| |
| named_fields = [ |
| (name, value) |
| for name, value in ast.iter_fields(node) |
| if name not in SKIP_DUMP_FIELDS |
| ] |
| if not named_fields: |
| print("{0}>".format(head)) |
| elif len(named_fields) == 1 and _is_simple_value(named_fields[0][1]): |
| field_name, value = named_fields[0] |
| print("{0} {1}: {2!r}>".format(head, field_name, value)) |
| else: |
| print(head) |
| if 0: |
| print("{0}# mro: {1}".format( |
| indent, ", ".join(c.__name__ for c in node.__class__.__mro__[1:]), |
| )) |
| next_indent = indent + " " |
| for field_name, value in named_fields: |
| prefix = "{0}{1}:".format(next_indent, field_name) |
| if _is_simple_value(value): |
| print("{0} {1!r}".format(prefix, value)) |
| elif isinstance(value, list): |
| print("{0} [".format(prefix)) |
| for n in value: |
| ast_dump(n, depth + 8) |
| print("{0}]".format(next_indent)) |
| else: |
| print(prefix) |
| ast_dump(value, depth + 8) |
| |
| print("{0}>".format(indent)) |
