diff options
| -rw-r--r-- | ChangeLog | 12 | ||||
| -rw-r--r-- | doc/faq.rst | 17 | ||||
| -rw-r--r-- | pylint/lint.py | 14 |
3 files changed, 41 insertions, 2 deletions
@@ -7,6 +7,18 @@ ChangeLog for Pylint abstract-class-not-used. These warnings don't add any real value and they don't imply errors or problems in the code. + * Added a new option for controlling the peephole optimizer in astroid. + The option ``--optimize-ast`` will control the peephole optimizer, + which is used to optimize a couple of AST subtrees. The current problem + solved by the peephole optimizer is when multiple joined strings, + with the addition operator, are encountered. If the numbers of such + strings is high enough, Pylint will then fail with a maximum recursion + depth exceeded error, due to its visitor architecture. The peephole + just transforms such calls, if it can, into the final resulting string + and this exhibit a problem, because the visit_binop method stops being + called (in the optimized AST it will be a Const node). + + 2015-03-11 -- 1.4.2 * Don't require a docstring for empty modules. Closes issue #261. diff --git a/doc/faq.rst b/doc/faq.rst index a42080e..1ce9a3e 100644 --- a/doc/faq.rst +++ b/doc/faq.rst @@ -261,12 +261,25 @@ mangled sys.path. Pylint doesn't import any of the candidate modules and thus doesn't include any of import's side effects (good and bad). It traverses an AST representation of the code. -6.3 I think I found a bug in Pylint. What should I do? +6.3 Pylint keeps crashing with `Maximum recursion depth exceeded` +----------------------------------------------------------------- + +Pylint can crash with this error if you have a string in your analyzed +program, created by joining a lot of strings with the addition operator. +Due to how Pylint works, visiting nodes on a AST tree and due to how +the BinOp node is represented (the node which represents the string '1+1' +for instance), the same visit method will be called over and over again, leading +to a maximum recursion error. You can alleviate this problem by passing +the flag `--optimize-ast=y` to Pylint. This will activate an optimization +which will transform such AST subtrees into the final resulting string. +This flag is off by default. If this is not the case, please report a bug! + +6.4 I think I found a bug in Pylint. What should I do? ------------------------------------------------------- Read http://docs.pylint.org/contribute#bug-reports-feedback -6.4 I have a question about Pylint that isn't answered here. +6.5 I have a question about Pylint that isn't answered here. ------------------------------------------------------------ Read http://docs.pylint.org/contribute#mailing-lists diff --git a/pylint/lint.py b/pylint/lint.py index eb8f706..b96a4ca 100644 --- a/pylint/lint.py +++ b/pylint/lint.py @@ -406,6 +406,19 @@ class PyLinter(configuration.OptionsManagerMixIn, ' loading into the active Python interpreter and may run' ' arbitrary code')} ), + + ('optimize-ast', + {'type': 'yn', 'metavar': '<yn>', 'default': False, + 'help': ('Allow optimization of some AST trees. This will ' + 'activate a peephole AST optimizer, which will ' + 'apply various small optimizations. For instance, ' + 'it can be used to obtain the result of joining ' + 'multiple strings with the addition operator. ' + 'Joining a lot of strings can lead to a maximum ' + 'recursion error in Pylint and this flag can prevent ' + 'that. It has one side effect, the resulting AST ' + 'will be different than the one from reality.')} + ), ) option_groups = ( @@ -940,6 +953,7 @@ class PyLinter(configuration.OptionsManagerMixIn, self.stats = {'by_module' : {}, 'by_msg' : {}, } + MANAGER.optimize_ast = self.config.optimize_ast MANAGER.always_load_extensions = self.config.unsafe_load_any_extension MANAGER.extension_package_whitelist.update( self.config.extension_pkg_whitelist) |