tests/heredoctest.py

tracing: new module to make tracing events in hg easier

This lives in hgdemandimport because I want to instrument a bunch of
low-level stuff including the bare `hg` script and demandimport, so it
can't live at a higher layer.

Differential Revision: https://phab.mercurial-scm.org/D4344

from __future__ import absolute_import, print_function

import sys

globalvars = {}
lines = sys.stdin.readlines()
while lines:
    l = lines.pop(0)
    if l.startswith('SALT'):
        print(l[:-1])
    elif l.startswith('>>> '):
        snippet = l[4:]
        while lines and lines[0].startswith('... '):
            l = lines.pop(0)
            snippet += l[4:]
        c = compile(snippet, '<heredoc>', 'single')
        try:
            exec(c, globalvars)
        except Exception as inst:
            print(repr(inst))