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"""Getting specific information for ImportError"""
import re
import sys
from typing import List, Optional, Tuple
from .. import debug_helper
from ..ft_gettext import current_lang, please_report
from ..message_parser import get_parser
from ..path_info import path_utils
from ..tb_data import TracebackData # for type checking only
from ..typing_info import CauseInfo # for type checking only
from ..utils import get_similar_words, list_to_string
parser = get_parser(ImportError)
_ = current_lang.translate
@parser._add
def partially_initialized_module(message: str, tb_data: TracebackData) -> CauseInfo:
# Python 3.8+
pattern = re.compile(
r"cannot import name '(.*)' from partially initialized module '(.*)'"
)
match = re.search(pattern, message)
if not match:
return {}
if "circular import" in message:
return cannot_import_name_from(
match[1], match[2], tb_data, add_circular_hint=False
)
# I thought I saw such a case where "circular import" was not added
# but have not been able to find it again.
return cannot_import_name_from(match[1], match[2], tb_data) # pragma: no cover
@parser._add
def _cannot_import_name_from(message: str, tb_data: TracebackData) -> CauseInfo:
# Python 3.7+
pattern = re.compile(r"cannot import name '(.*)' from '(.*)'")
match = re.search(pattern, message)
return cannot_import_name_from(match[1], match[2], tb_data) if match else {}
@parser._add
def _cannot_import_name(message: str, tb_data: TracebackData) -> CauseInfo:
# Python 3.6 does not give us more information
pattern = re.compile(r"cannot import name '(.*)'")
match = re.search(pattern, message)
return cannot_import_name(match[1], tb_data) if match else {}
def cannot_import_name_from(
name: str, module: str, tb_data: TracebackData, add_circular_hint: bool = True
) -> CauseInfo:
hint = None
circular_info = None
modules_imported = extract_import_data_from_traceback(tb_data)
if modules_imported:
circular_info = find_circular_import(modules_imported)
if circular_info and add_circular_hint:
hint = _("You have a circular import.\n")
# Python 3.8+ adds a similar hint on its own.
cause = _(
"The object that could not be imported is `{name}`.\n"
"The module or package where it was \n"
"expected to be found is `{module}`.\n"
).format(name=name, module=module)
if circular_info:
if hint is None:
return {"cause": cause + "\n" + circular_info}
return {"cause": cause + "\n" + circular_info, "suggest": hint}
if not add_circular_hint: # pragma: no cover
debug_helper.log("New example to add")
return {
"cause": cause
+ "\n"
+ _(
"Python indicated that you have a circular import.\n"
"This can occur if executing the code in module 'A'\n"
"results in executing the code in module 'B' where\n"
"an attempt to import a name from module 'A' is made\n"
"before the execution of the code in module 'A' had been completed.\n"
)
}
try:
mod = sys.modules[module]
except Exception: # noqa # pragma: no cover
cause += "\n" + _(
"Inconsistent state: `'{module}'` was apparently not imported.\n"
"As a result, no further analysis can be done.\n"
).format(module=module)
return {"cause": cause}
similar = get_similar_words(name, dir(mod))
if not similar:
return {"cause": cause}
if len(similar) == 1:
hint = _("Did you mean `{name}`?\n").format(name=similar[0])
cause = _(
"Perhaps you meant to import `{correct}` (from `{module}`) "
"instead of `{typo}`\n"
).format(correct=similar[0], typo=name, module=module)
else:
candidates = list_to_string(similar)
hint = _("Did you mean one of the following: `{names}`?\n").format(
names=candidates
)
cause = _(
"Instead of trying to import `{typo}` from `{module}`, \n"
"perhaps you meant to import one of \n"
"the following names which are found in module `{module}`:\n"
"`{candidates}`\n"
).format(candidates=candidates, typo=name, module=module)
return {"cause": cause, "suggest": hint}
def cannot_import_name(name: str, tb_data: TracebackData) -> CauseInfo:
# Python 3.6 does not give us the name of the module
pattern = re.compile(r"from (.*) import")
match = re.search(pattern, tb_data.bad_line)
if not match: # pragma: no cover
debug_helper.log("New example to consider.")
return {
"cause": _("The object that could not be imported is `{name}`.\n").format(
name=name
)
+ please_report()
}
return cannot_import_name_from(name, match[1], tb_data)
Modules = List[Tuple[str, str]]
def extract_import_data_from_traceback(tb_data: TracebackData) -> Modules:
"""Attempts to extract the list of imported modules from the traceback information"""
pattern_file = re.compile(r'^File "(.*)", line', re.M)
pattern_from = re.compile(r"^from (.*) import", re.M)
pattern_import = re.compile(r"^import (.*)", re.M)
modules_imported = []
tb_lines = tb_data.simulated_python_traceback.split("\n")
current_file = ""
for line in tb_lines:
line = line.strip()
match_file = re.search(pattern_file, line)
match_from = re.search(pattern_from, line)
match_import = re.search(pattern_import, line)
if match_file:
current_file = path_utils.shorten_path(match_file[1])
elif match_from or match_import:
if match_from:
modules_imported.append((current_file, match_from[1]))
else:
module = match_import[1]
if "," in module: # multiple modules imported on same line
modules = module.split(",")
for mod in modules:
modules_imported.append(
(current_file, mod.replace("(", "").strip())
)
else:
modules_imported.append((current_file, module))
current_file = ""
return modules_imported
def find_circular_import(modules_imported: Modules) -> Optional[str]:
"""This attempts to find circular imports."""
last_file, last_module = modules_imported[-1]
for file, module in modules_imported[:-1]:
if module == last_module:
return _(
"The problem was likely caused by what is known as a 'circular import'.\n"
"First, Python imported and started executing the code in file\n"
" '{file}'.\n"
"which imports module `{last_module}`.\n"
"During this process, the code in another file,\n"
" '{last_file}'\n"
"was executed. However in this last file, an attempt was made\n"
"to import the original module `{last_module}`\n"
"a second time, before Python had completed the first import.\n"
).format(
file=file, last_file=last_file, module=module, last_module=last_module
)
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