Mercurial > hg
view contrib/import-checker.py @ 25676:ec9c258e666d stable
templater: parse \"...\" as string for 2.9.2-3.4 compatibility (issue4733)
As of Mercurial 3.4, there were several syntax rules to process nested
template strings. Unfortunately, they were inconsistent and conflicted
each other.
a. buildmap() rule
- template string is _parsed_ as string, and parsed as template
- <\"> is not allowed in nested template:
{xs % "{f(\"{x}\")}"} -> parse error
- template escaping <\{> is handled consistently:
{xs % "\{x}"} -> escaped
b. _evalifliteral() rule
- template string is _interpreted_ as string, and parsed as template
in crafted environment to avoid double processing of escape sequences
- <\"> is allowed in nested template:
{if(x, "{f(\"{x}\")}")}
- <\{> and escape sequences in string literal in nested template are not
handled well
c. pad() rule
- template string is first interpreted as string, and parsed as template,
which means escape sequences are processed twice
- <\"> is allowed in nested template:
{pad("{xs % \"{x}\"}', 10)}
Because of the issue of template escaping, issue4714, 7298da81f5a9 (in stable)
unified the rule (b) to (a). Then, 576d6c74784b (in default) unified the rule
(c) to (b) = (a). But they disabled the following syntax that was somewhat
considered valid.
{if(rev, "{if(rev, \"{rev}\")}")}
{pad("{files % \"{file}\"}", 10)}
So, this patch introduces \"...\" literal to work around the escaped-quoted
nested template strings. Because this parsing rule exists only for the backward
compatibility, it is designed to copy the behavior of old _evalifliteral() as
possible.
Future patches will introduce a better parsing rule similar to a command
substitution of POSIX shells or a string interpolation of Ruby, where extra
escapes won't be necessary at all.
{pad("{files % "{file}"}", 10)}
~~~~~~~~~~~~~~~~~~
parsed as a template, not as a string
Because <\> character wasn't allowed in a template fragment, this patch won't
introduce more breakages. But the syntax of nested templates are interpreted
differently by people, there might be unknown issues. So if we want, we could
instead remove db7463aa080f, 890845af1ac2 and 7298da81f5a9 from the stable
branch as the bug fixed by these patches existed for longer periods.
554d6fcc3c8, "strip single backslash before quotation mark in quoted template",
should be superseded by this patch. I'll remove it later.
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Thu, 25 Jun 2015 22:07:38 +0900 |
parents | fbdbff1b486a |
children | 723e364488f4 |
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 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: print 'Usage: %s file [file] [file] ...' return 1 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)))