tests: add test of stream clone of repo that is changing This reveals an error introduced by 9fea6b38a8da.

chgserver: handle ParseError during validate Currently the validate command in chgserver expects config can be loaded without issues but the config can be broken and chg will print a stacktrace instead of the parsing error, if a chg server is already running. This patch adds a handler for ParseError in validate and a new instruction "exit" to make the client exit without abortmsg. A test is also added to make sure it will behave as expected.

dispatch: extract common logic for handling ParseError The way ParseError is handled at two different places in dispatch.py is the same. Move common logic into _formatparse.

chgserver: resolve relative path before sending via system channel The chgserver may have a different cwd from the client because of the side effect of "--cwd" and other possible os.chdir done by extensions. Therefore relative paths can be misunderstood by the client. This patch solves it by expanding relative cwd path to absolute one before sending them via the 'S' channel. It can help chg to pass a testcase in test-alias.t later.

mercurial: use pure Python module policy on Python 3 The C extensions don't yet work with Python 3. Let's minimize the work required to get Mercurial running on Python 3 by always using the pure Python module policy on Python 3.

chg: provide early exception to user See the previous patch for details. Since the socket will be closed by the server, handleresponse() will never return: Traceback (most recent call last): ... chg: abort: failed to read channel

cmdserver: write early exception to 'e' channel in 'unix' mode In 'unix' mode, the server is typically detached from the console. Therefore a client couldn't see the exception that occurred while instantiating the server object. This patch tries to catch the early error and send it to 'e' channel even if the server isn't instantiated yet. This means the error may be sent before the initial hello message. So it's up to the client implementation whether to handle the early error message or error out as protocol violation. The error handling code is also copied to chgserver.py. I'll factor out them later if we manage to get chg passes the test suite.

contrib: make memory.py use absolute_import

check-code: use absolute_import and print_function

encoding: use range() instead of xrange() Python 3 doesn't have xrange(). Instead, range() on Python 3 is a generator, like xrange() is on Python 2. The benefits of xrange() over range() are when there are very large ranges that are too expensive to pre-allocate. The code here is only creating <128 values, so the benefits of xrange() should be negligible. With this patch, encoding.py imports safely on Python 3.