import-checker: add xargs like mode
Before this patch, "import-check.py" is invoked via "xargs" in
"test-module-imports.t", but it doesn't ensure that
"import-checker.py" is certainly invoked with all mercurial specific
files at once.
"xargs" may invoke specified command multiple times with part of
arguments given from stdin: according to "xargs(1)" man page, this
dividing arguments is system-dependent.
This patch adds "xargs" like mode to "import-checker.py".
This can ensure that "import-checker.py" is certainly invoked with all
mercurial specific files at once in "test-module-imports.t". This is
assumed by subsequent patches.
import ast
import os
import sys
# Import a minimal set of stdlib modules needed for list_stdlib_modules()
# to work when run from a virtualenv. The modules were chosen empirically
# so that the return value matches the return value without virtualenv.
import BaseHTTPServer
import zlib
def dotted_name_of_path(path, trimpure=False):
"""Given a relative path to a source file, return its dotted module name.
>>> dotted_name_of_path('mercurial/error.py')
'mercurial.error'
>>> dotted_name_of_path('mercurial/pure/parsers.py', trimpure=True)
'mercurial.parsers'
>>> dotted_name_of_path('zlibmodule.so')
'zlib'
"""
parts = path.split('/')
parts[-1] = parts[-1].split('.', 1)[0] # remove .py and .so and .ARCH.so
if parts[-1].endswith('module'):
parts[-1] = parts[-1][:-6]
if trimpure:
return '.'.join(p for p in parts if p != 'pure')
return '.'.join(parts)
def list_stdlib_modules():
"""List the modules present in the stdlib.
>>> mods = set(list_stdlib_modules())
>>> 'BaseHTTPServer' in mods
True
os.path isn't really a module, so it's missing:
>>> 'os.path' in mods
False
sys requires special treatment, because it's baked into the
interpreter, but it should still appear:
>>> 'sys' in mods
True
>>> 'collections' in mods
True
>>> 'cStringIO' in mods
True
"""
for m in sys.builtin_module_names:
yield m
# These modules only exist on windows, but we should always
# consider them stdlib.
for m in ['msvcrt', '_winreg']:
yield m
# These get missed too
for m in 'ctypes', 'email':
yield m
yield 'builtins' # python3 only
for m in 'fcntl', 'grp', 'pwd', 'termios': # Unix only
yield m
stdlib_prefixes = set([sys.prefix, sys.exec_prefix])
# We need to supplement the list of prefixes for the search to work
# when run from within a virtualenv.
for mod in (BaseHTTPServer, zlib):
try:
# Not all module objects have a __file__ attribute.
filename = mod.__file__
except AttributeError:
continue
dirname = os.path.dirname(filename)
for prefix in stdlib_prefixes:
if dirname.startswith(prefix):
# Then this directory is redundant.
break
else:
stdlib_prefixes.add(dirname)
for libpath in sys.path:
# We want to walk everything in sys.path that starts with
# something in stdlib_prefixes. check-code suppressed because
# the ast module used by this script implies the availability
# of any().
if not any(libpath.startswith(p) for p in stdlib_prefixes): # no-py24
continue
if 'site-packages' in libpath:
continue
for top, dirs, files in os.walk(libpath):
for name in files:
if name == '__init__.py':
continue
if not (name.endswith('.py') or name.endswith('.so')
or name.endswith('.pyd')):
continue
full_path = os.path.join(top, name)
if 'site-packages' in full_path:
continue
rel_path = full_path[len(libpath) + 1:]
mod = dotted_name_of_path(rel_path)
yield mod
stdlib_modules = set(list_stdlib_modules())
def imported_modules(source, ignore_nested=False):
"""Given the source of a file as a string, yield the names
imported by that file.
Args:
source: The python source to examine as a string.
ignore_nested: If true, import statements that do not start in
column zero will be ignored.
Returns:
A list of module names imported by the given source.
>>> sorted(imported_modules(
... 'import foo ; from baz import bar; import foo.qux'))
['baz.bar', 'foo', 'foo.qux']
>>> sorted(imported_modules(
... '''import foo
... def wat():
... import bar
... ''', ignore_nested=True))
['foo']
"""
for node in ast.walk(ast.parse(source)):
if ignore_nested and getattr(node, 'col_offset', 0) > 0:
continue
if isinstance(node, ast.Import):
for n in node.names:
yield n.name
elif isinstance(node, ast.ImportFrom):
prefix = node.module + '.'
for n in node.names:
yield prefix + n.name
def verify_stdlib_on_own_line(source):
"""Given some python source, verify that stdlib imports are done
in separate statements from relative local module imports.
Observing this limitation is important as it works around an
annoying lib2to3 bug in relative import rewrites:
http://bugs.python.org/issue19510.
>>> list(verify_stdlib_on_own_line('import sys, foo'))
['mixed imports\\n stdlib: sys\\n relative: foo']
>>> list(verify_stdlib_on_own_line('import sys, os'))
[]
>>> list(verify_stdlib_on_own_line('import foo, bar'))
[]
"""
for node in ast.walk(ast.parse(source)):
if isinstance(node, ast.Import):
from_stdlib = {False: [], True: []}
for n in node.names:
from_stdlib[n.name in stdlib_modules].append(n.name)
if from_stdlib[True] and from_stdlib[False]:
yield ('mixed imports\n stdlib: %s\n relative: %s' %
(', '.join(sorted(from_stdlib[True])),
', '.join(sorted(from_stdlib[False]))))
class CircularImport(Exception):
pass
def checkmod(mod, imports):
shortest = {}
visit = [[mod]]
while visit:
path = visit.pop(0)
for i in sorted(imports.get(path[-1], [])):
if i not in stdlib_modules and not i.startswith('mercurial.'):
i = mod.rsplit('.', 1)[0] + '.' + i
if len(path) < shortest.get(i, 1000):
shortest[i] = len(path)
if i in path:
if i == path[0]:
raise CircularImport(path)
continue
visit.append(path + [i])
def rotatecycle(cycle):
"""arrange a cycle so that the lexicographically first module listed first
>>> rotatecycle(['foo', 'bar'])
['bar', 'foo', 'bar']
"""
lowest = min(cycle)
idx = cycle.index(lowest)
return cycle[idx:] + cycle[:idx] + [lowest]
def find_cycles(imports):
"""Find cycles in an already-loaded import graph.
>>> imports = {'top.foo': ['bar', 'os.path', 'qux'],
... 'top.bar': ['baz', 'sys'],
... 'top.baz': ['foo'],
... 'top.qux': ['foo']}
>>> print '\\n'.join(sorted(find_cycles(imports)))
top.bar -> top.baz -> top.foo -> top.bar
top.foo -> top.qux -> top.foo
"""
cycles = set()
for mod in sorted(imports.iterkeys()):
try:
checkmod(mod, imports)
except CircularImport, e:
cycle = e.args[0]
cycles.add(" -> ".join(rotatecycle(cycle)))
return cycles
def _cycle_sortkey(c):
return len(c), c
def main(argv):
if len(argv) < 2 or (argv[1] == '-' and len(argv) > 2):
print 'Usage: %s {-|file [file] [file] ...}'
return 1
if argv[1] == '-':
argv = argv[:1]
argv.extend(l.rstrip() for l in sys.stdin.readlines())
used_imports = {}
any_errors = False
for source_path in argv[1:]:
f = open(source_path)
modname = dotted_name_of_path(source_path, trimpure=True)
src = f.read()
used_imports[modname] = sorted(
imported_modules(src, ignore_nested=True))
for error in verify_stdlib_on_own_line(src):
any_errors = True
print source_path, error
f.close()
cycles = find_cycles(used_imports)
if cycles:
firstmods = set()
for c in sorted(cycles, key=_cycle_sortkey):
first = c.split()[0]
# As a rough cut, ignore any cycle that starts with the
# same module as some other cycle. Otherwise we see lots
# of cycles that are effectively duplicates.
if first in firstmods:
continue
print 'Import cycle:', c
firstmods.add(first)
any_errors = True
return not any_errors
if __name__ == '__main__':
sys.exit(int(main(sys.argv)))