Mercurial > hg
view mercurial/hook.py @ 25561:50a6c3c55db1 stable
parsers: do not cache RevlogError type (issue4451)
Index lookups raise RevlogError when the lookup fails. The previous
implementation was caching a reference to the RevlogError type in a
static variable. This assumed that the "mercurial.error" module was
only loaded once and there was only a single copy of it floating
around in memory. Unfortunately, in some situations - including
certain mod_wsgi configurations - this was not the case: the
"mercurial.error" module could be reloaded. It was possible for a
"RevlogError" reference from the first interpreter to be used by
a second interpreter. While the underlying thing was a
"mercurial.error.RevlogError," the object IDs were different, so
the Python code in revlog.py was failing to catch the exception! This
error has existed since the C index lookup code was implemented in
changeset e8d37b78acfb, which was first released in Mercurial 2.2 in
2012.
http://emptysqua.re/blog/python-c-extensions-and-mod-wsgi/#static-variables-are-shared
contains more details.
This patch removes the caching of the RevlogError type from the
function.
Since pretty much the entire function was refactored and the return
value of the function wasn't used, I changed the function signature
to not return anything.
For reasons unknown to me, we were calling PyErr_SetObject()
with the type of RevlogError and an instance of RevlogError. This
was equivalent to the Python code "raise RevlogError(RevlogError)".
This seemed wonky and completely unnecessary. The Python code only
cares about the type of the exception, not its contents. So I got
rid of this complexity.
This is my first Python C extension patch. Please give extra scrutiny
to it during review.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 12 Jun 2015 14:43:59 -0700 |
parents | 2abbf4750915 |
children | 7046c7e7fcb4 |
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# hook.py - hook support for mercurial # # Copyright 2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from i18n import _ import os, sys, time import extensions, util, demandimport, error def _pythonhook(ui, repo, name, hname, funcname, args, throw): '''call python hook. hook is callable object, looked up as name in python module. if callable returns "true", hook fails, else passes. if hook raises exception, treated as hook failure. exception propagates if throw is "true". reason for "true" meaning "hook failed" is so that unmodified commands (e.g. mercurial.commands.update) can be run as hooks without wrappers to convert return values.''' if callable(funcname): obj = funcname funcname = obj.__module__ + "." + obj.__name__ else: d = funcname.rfind('.') if d == -1: raise util.Abort(_('%s hook is invalid ("%s" not in ' 'a module)') % (hname, funcname)) modname = funcname[:d] oldpaths = sys.path if util.mainfrozen(): # binary installs require sys.path manipulation modpath, modfile = os.path.split(modname) if modpath and modfile: sys.path = sys.path[:] + [modpath] modname = modfile demandimportenabled = demandimport.isenabled() if demandimportenabled: demandimport.disable() try: try: obj = __import__(modname) except ImportError: e1 = sys.exc_type, sys.exc_value, sys.exc_traceback try: # extensions are loaded with hgext_ prefix obj = __import__("hgext_%s" % modname) except ImportError: e2 = sys.exc_type, sys.exc_value, sys.exc_traceback if ui.tracebackflag: ui.warn(_('exception from first failed import ' 'attempt:\n')) ui.traceback(e1) if ui.tracebackflag: ui.warn(_('exception from second failed import ' 'attempt:\n')) ui.traceback(e2) raise util.Abort(_('%s hook is invalid ' '(import of "%s" failed)') % (hname, modname)) finally: if demandimportenabled: demandimport.enable() sys.path = oldpaths try: for p in funcname.split('.')[1:]: obj = getattr(obj, p) except AttributeError: raise util.Abort(_('%s hook is invalid ' '("%s" is not defined)') % (hname, funcname)) if not callable(obj): raise util.Abort(_('%s hook is invalid ' '("%s" is not callable)') % (hname, funcname)) ui.note(_("calling hook %s: %s\n") % (hname, funcname)) starttime = time.time() try: try: # redirect IO descriptors to the ui descriptors so hooks # that write directly to these don't mess up the command # protocol when running through the command server old = sys.stdout, sys.stderr, sys.stdin sys.stdout, sys.stderr, sys.stdin = ui.fout, ui.ferr, ui.fin r = obj(ui=ui, repo=repo, hooktype=name, **args) except KeyboardInterrupt: raise except Exception, exc: if isinstance(exc, util.Abort): ui.warn(_('error: %s hook failed: %s\n') % (hname, exc.args[0])) else: ui.warn(_('error: %s hook raised an exception: ' '%s\n') % (hname, exc)) if throw: raise ui.traceback() return True finally: sys.stdout, sys.stderr, sys.stdin = old duration = time.time() - starttime ui.log('pythonhook', 'pythonhook-%s: %s finished in %0.2f seconds\n', name, funcname, duration) if r: if throw: raise error.HookAbort(_('%s hook failed') % hname) ui.warn(_('warning: %s hook failed\n') % hname) return r def _exthook(ui, repo, name, cmd, args, throw): ui.note(_("running hook %s: %s\n") % (name, cmd)) starttime = time.time() env = {} for k, v in args.iteritems(): if callable(v): v = v() if isinstance(v, dict): # make the dictionary element order stable across Python # implementations v = ('{' + ', '.join('%r: %r' % i for i in sorted(v.iteritems())) + '}') env['HG_' + k.upper()] = v if repo: cwd = repo.root else: cwd = os.getcwd() r = ui.system(cmd, environ=env, cwd=cwd) duration = time.time() - starttime ui.log('exthook', 'exthook-%s: %s finished in %0.2f seconds\n', name, cmd, duration) if r: desc, r = util.explainexit(r) if throw: raise error.HookAbort(_('%s hook %s') % (name, desc)) ui.warn(_('warning: %s hook %s\n') % (name, desc)) return r def _allhooks(ui): hooks = [] for name, cmd in ui.configitems('hooks'): if not name.startswith('priority'): priority = ui.configint('hooks', 'priority.%s' % name, 0) hooks.append((-priority, len(hooks), name, cmd)) return [(k, v) for p, o, k, v in sorted(hooks)] _redirect = False def redirect(state): global _redirect _redirect = state def hook(ui, repo, name, throw=False, **args): if not ui.callhooks: return False r = False oldstdout = -1 try: for hname, cmd in _allhooks(ui): if hname.split('.')[0] != name or not cmd: continue if oldstdout == -1 and _redirect: try: stdoutno = sys.__stdout__.fileno() stderrno = sys.__stderr__.fileno() # temporarily redirect stdout to stderr, if possible if stdoutno >= 0 and stderrno >= 0: sys.__stdout__.flush() oldstdout = os.dup(stdoutno) os.dup2(stderrno, stdoutno) except (OSError, AttributeError): # files seem to be bogus, give up on redirecting (WSGI, etc) pass if callable(cmd): r = _pythonhook(ui, repo, name, hname, cmd, args, throw) or r elif cmd.startswith('python:'): if cmd.count(':') >= 2: path, cmd = cmd[7:].rsplit(':', 1) path = util.expandpath(path) if repo: path = os.path.join(repo.root, path) try: mod = extensions.loadpath(path, 'hghook.%s' % hname) except Exception: ui.write(_("loading %s hook failed:\n") % hname) raise hookfn = getattr(mod, cmd) else: hookfn = cmd[7:].strip() r = _pythonhook(ui, repo, name, hname, hookfn, args, throw) or r else: r = _exthook(ui, repo, hname, cmd, args, throw) or r # The stderr is fully buffered on Windows when connected to a pipe. # A forcible flush is required to make small stderr data in the # remote side available to the client immediately. sys.stderr.flush() finally: if _redirect and oldstdout >= 0: os.dup2(oldstdout, stdoutno) os.close(oldstdout) return r