Mercurial > hg
view contrib/import-checker.py @ 25708:d3d32643c060
wireproto: correctly escape batched args and responses (issue4739)
This issue appears to be as old as wireproto batching itself: I can
reproduce the failure as far back as 08ef6b5f3715 trivially by
rebasing the test changes in this patch, which was back in the 1.9
era. I didn't test before that change, because prior to that the
testfile has a different name and I'm lazy.
Note that the test thought it was checking this case, but it actually
wasn't: it put a literal ; in the arg and response for its greet
command, but the mangle/unmangle step defined in the test meant that
instead of "Fo, =;o" going over the wire, "Gp-!><p" went instead,
which doesn't contain any special characters (those being [.=;]) and
thus not exercising the escaping. The test has been updated to use
pre-unmangled special characters, so the request is now "Fo+<:o",
which mangles to "Gp,=;p". I have confirmed that the test fails
without the adjustment to the escaping rules in wireproto.py.
No existing clients of RPC batching were depending on the old behavior
in any way. The only *actual* users of batchable RPCs in core were:
1) largefiles, wherein it batches up many statlfile calls. It sends
hexlified hashes over the wire and gets a 0, 1, or 2 back as a
response. No risk of special characters.
2) setdiscovery, which was using heads() and known(), both of which
communicate via hexlified nodes. Again, no risk of special characters.
Since the escaping functionality has been completely broken since it
was introduced, we know that it has no users. As such, we can change
the escaping mechanism without having to worry about backwards
compatibility issues.
For the curious, this was detected by chance: it happens that the
lz4-compressed text of a test file for remotefilelog compressed to
something containing a ;, which then caused the failure when I moved
remotefilelog to using batching for file content fetching.
author | Augie Fackler <augie@google.com> |
---|---|
date | Tue, 30 Jun 2015 19:19:17 -0400 |
parents | 1a6a117d0b95 |
children | cd1daab5d036 |
line wrap: on
line source
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 # Whitelist of modules that symbols can be directly imported from. allowsymbolimports = ( '__future__', 'mercurial.i18n', 'mercurial.node', ) # Modules that must be aliased because they are commonly confused with # common variables and can create aliasing and readability issues. requirealias = { 'ui': 'uimod', } def usingabsolute(root): """Whether absolute imports are being used.""" if sys.version_info[0] >= 3: return True for node in ast.walk(root): if isinstance(node, ast.ImportFrom): if node.module == '__future__': for n in node.names: if n.name == 'absolute_import': return True return False 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 fromlocalfunc(modulename, localmods): """Get a function to examine which locally defined module the target source imports via a specified name. `modulename` is an `dotted_name_of_path()`-ed source file path, which may have `.__init__` at the end of it, of the target source. `localmods` is a dict (or set), of which key is an absolute `dotted_name_of_path()`-ed source file path of locally defined (= Mercurial specific) modules. This function assumes that module names not existing in `localmods` are ones of Python standard libarary. This function returns the function, which takes `name` argument, and returns `(absname, dottedpath, hassubmod)` tuple if `name` matches against locally defined module. Otherwise, it returns False. It is assumed that `name` doesn't have `.__init__`. `absname` is an absolute module name of specified `name` (e.g. "hgext.convert"). This can be used to compose prefix for sub modules or so. `dottedpath` is a `dotted_name_of_path()`-ed source file path (e.g. "hgext.convert.__init__") of `name`. This is used to look module up in `localmods` again. `hassubmod` is whether it may have sub modules under it (for convenient, even though this is also equivalent to "absname != dottednpath") >>> localmods = {'foo.__init__': True, 'foo.foo1': True, ... 'foo.bar.__init__': True, 'foo.bar.bar1': True, ... 'baz.__init__': True, 'baz.baz1': True } >>> fromlocal = fromlocalfunc('foo.xxx', localmods) >>> # relative >>> fromlocal('foo1') ('foo.foo1', 'foo.foo1', False) >>> fromlocal('bar') ('foo.bar', 'foo.bar.__init__', True) >>> fromlocal('bar.bar1') ('foo.bar.bar1', 'foo.bar.bar1', False) >>> # absolute >>> fromlocal('baz') ('baz', 'baz.__init__', True) >>> fromlocal('baz.baz1') ('baz.baz1', 'baz.baz1', False) >>> # unknown = maybe standard library >>> fromlocal('os') False >>> fromlocal(None, 1) ('foo', 'foo.__init__', True) >>> fromlocal2 = fromlocalfunc('foo.xxx.yyy', localmods) >>> fromlocal2(None, 2) ('foo', 'foo.__init__', True) """ prefix = '.'.join(modulename.split('.')[:-1]) if prefix: prefix += '.' def fromlocal(name, level=0): # name is None when relative imports are used. if name is None: # If relative imports are used, level must not be absolute. assert level > 0 candidates = ['.'.join(modulename.split('.')[:-level])] else: # Check relative name first. candidates = [prefix + name, name] for n in candidates: if n in localmods: return (n, n, False) dottedpath = n + '.__init__' if dottedpath in localmods: return (n, dottedpath, True) return False return fromlocal 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, modulename, localmods, 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. modulename: of specified python source (may have `__init__`) localmods: dict of locally defined module names (may have `__init__`) ignore_nested: If true, import statements that do not start in column zero will be ignored. Returns: A list of absolute module names imported by the given source. >>> modulename = 'foo.xxx' >>> localmods = {'foo.__init__': True, ... 'foo.foo1': True, 'foo.foo2': True, ... 'foo.bar.__init__': True, 'foo.bar.bar1': True, ... 'baz.__init__': True, 'baz.baz1': True } >>> # standard library (= not locally defined ones) >>> sorted(imported_modules( ... 'from stdlib1 import foo, bar; import stdlib2', ... modulename, localmods)) [] >>> # relative importing >>> sorted(imported_modules( ... 'import foo1; from bar import bar1', ... modulename, localmods)) ['foo.bar.__init__', 'foo.bar.bar1', 'foo.foo1'] >>> sorted(imported_modules( ... 'from bar.bar1 import name1, name2, name3', ... modulename, localmods)) ['foo.bar.bar1'] >>> # absolute importing >>> sorted(imported_modules( ... 'from baz import baz1, name1', ... modulename, localmods)) ['baz.__init__', 'baz.baz1'] >>> # mixed importing, even though it shouldn't be recommended >>> sorted(imported_modules( ... 'import stdlib, foo1, baz', ... modulename, localmods)) ['baz.__init__', 'foo.foo1'] >>> # ignore_nested >>> sorted(imported_modules( ... '''import foo ... def wat(): ... import bar ... ''', modulename, localmods)) ['foo.__init__', 'foo.bar.__init__'] >>> sorted(imported_modules( ... '''import foo ... def wat(): ... import bar ... ''', modulename, localmods, ignore_nested=True)) ['foo.__init__'] """ fromlocal = fromlocalfunc(modulename, localmods) 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: found = fromlocal(n.name) if not found: # this should import standard library continue yield found[1] elif isinstance(node, ast.ImportFrom): found = fromlocal(node.module, node.level) if not found: # this should import standard library continue absname, dottedpath, hassubmod = found yield dottedpath if not hassubmod: # examination of "node.names" should be redundant # e.g.: from mercurial.node import nullid, nullrev continue prefix = absname + '.' for n in node.names: found = fromlocal(prefix + n.name) if not found: # this should be a function or a property of "node.module" continue yield found[1] def verify_import_convention(module, source): """Verify imports match our established coding convention. We have 2 conventions: legacy and modern. The modern convention is in effect when using absolute imports. The legacy convention only looks for mixed imports. The modern convention is much more thorough. """ root = ast.parse(source) absolute = usingabsolute(root) if absolute: return verify_modern_convention(module, root) else: return verify_stdlib_on_own_line(root) def verify_modern_convention(module, root): """Verify a file conforms to the modern import convention rules. The rules of the modern convention are: * Ordering is stdlib followed by local imports. Each group is lexically sorted. * Importing multiple modules via "import X, Y" is not allowed: use separate import statements. * Importing multiple modules via "from X import ..." is allowed if using parenthesis and one entry per line. * Only 1 relative import statement per import level ("from .", "from ..") is allowed. * Relative imports from higher levels must occur before lower levels. e.g. "from .." must be before "from .". * Imports from peer packages should use relative import (e.g. do not "import mercurial.foo" from a "mercurial.*" module). * Symbols can only be imported from specific modules (see `allowsymbolimports`). For other modules, first import the module then assign the symbol to a module-level variable. In addition, these imports must be performed before other relative imports. This rule only applies to import statements outside of any blocks. * Relative imports from the standard library are not allowed. * Certain modules must be aliased to alternate names to avoid aliasing and readability problems. See `requirealias`. """ topmodule = module.split('.')[0] # Whether a local/non-stdlib import has been performed. seenlocal = False # Whether a relative, non-symbol import has been seen. seennonsymbolrelative = False # The last name to be imported (for sorting). lastname = None # Relative import levels encountered so far. seenlevels = set() for node in ast.walk(root): if isinstance(node, ast.Import): # Disallow "import foo, bar" and require separate imports # for each module. if len(node.names) > 1: yield 'multiple imported names: %s' % ', '.join( n.name for n in node.names) name = node.names[0].name asname = node.names[0].asname # Ignore sorting rules on imports inside blocks. if node.col_offset == 0: if lastname and name < lastname: yield 'imports not lexically sorted: %s < %s' % ( name, lastname) lastname = name # stdlib imports should be before local imports. stdlib = name in stdlib_modules if stdlib and seenlocal and node.col_offset == 0: yield 'stdlib import follows local import: %s' % name if not stdlib: seenlocal = True # Import of sibling modules should use relative imports. topname = name.split('.')[0] if topname == topmodule: yield 'import should be relative: %s' % name if name in requirealias and asname != requirealias[name]: yield '%s module must be "as" aliased to %s' % ( name, requirealias[name]) elif isinstance(node, ast.ImportFrom): # Resolve the full imported module name. if node.level > 0: fullname = '.'.join(module.split('.')[:-node.level]) if node.module: fullname += '.%s' % node.module else: assert node.module fullname = node.module topname = fullname.split('.')[0] if topname == topmodule: yield 'import should be relative: %s' % fullname # __future__ is special since it needs to come first and use # symbol import. if fullname != '__future__': if not fullname or fullname in stdlib_modules: yield 'relative import of stdlib module' else: seenlocal = True # Direct symbol import is only allowed from certain modules and # must occur before non-symbol imports. if node.module and node.col_offset == 0: if fullname not in allowsymbolimports: yield 'direct symbol import from %s' % fullname if seennonsymbolrelative: yield ('symbol import follows non-symbol import: %s' % fullname) if not node.module: assert node.level seennonsymbolrelative = True # Only allow 1 group per level. if node.level in seenlevels and node.col_offset == 0: yield 'multiple "from %s import" statements' % ( '.' * node.level) # Higher-level groups come before lower-level groups. if any(node.level > l for l in seenlevels): yield 'higher-level import should come first: %s' % ( fullname) seenlevels.add(node.level) # Entries in "from .X import ( ... )" lists must be lexically # sorted. lastentryname = None for n in node.names: if lastentryname and n.name < lastentryname: yield 'imports from %s not lexically sorted: %s < %s' % ( fullname, n.name, lastentryname) lastentryname = n.name if n.name in requirealias and n.asname != requirealias[n.name]: yield '%s from %s must be "as" aliased to %s' % ( n.name, fullname, requirealias[n.name]) def verify_stdlib_on_own_line(root): """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(ast.parse('import sys, foo'))) ['mixed imports\\n stdlib: sys\\n relative: foo'] >>> list(verify_stdlib_on_own_line(ast.parse('import sys, os'))) [] >>> list(verify_stdlib_on_own_line(ast.parse('import foo, bar'))) [] """ for node in ast.walk(root): 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 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. All module names recorded in `imports` should be absolute one. >>> imports = {'top.foo': ['top.bar', 'os.path', 'top.qux'], ... 'top.bar': ['top.baz', 'sys'], ... 'top.baz': ['top.foo'], ... 'top.qux': ['top.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 as 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()) localmods = {} used_imports = {} any_errors = False for source_path in argv[1:]: modname = dotted_name_of_path(source_path, trimpure=True) localmods[modname] = source_path for modname, source_path in sorted(localmods.iteritems()): f = open(source_path) src = f.read() used_imports[modname] = sorted( imported_modules(src, modname, localmods, ignore_nested=True)) for error in verify_import_convention(modname, 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)))