Add support to bin/tahoe for invoking a runner command prefixed with @, with the...

diff --git a/bin/tahoe-script.template b/bin/tahoe-script.template
index 10c8a006459e6e791d3360d6e2d6f789bebb830a..ec9f148b9660e436f6e684c31375874d4c61b54e 100644 (file)
--- a/bin/tahoe-script.template
+++ b/bin/tahoe-script.template
@@ -95,7 +95,22 @@ when you run "python setup.py install" (perhaps as "%s").
 ''' % (script, perhaps_installed_tahoe)
     sys.exit(1)
 
-command = prefix + [script] + args
+# Support indirection via another "runner" script (e.g. coverage).
+# For example: bin/tahoe @RUNNER RUNNER_ARGS @tahoe TAHOE_ARGS
+
+if len(args) >= 1 and args[0].startswith('@'):
+    runner = args[0][1:]
+    if runner.endswith('.py') or runner.endswith('.pyscript'):
+        prefix = [sys.executable]
+    else:
+        prefix = []
+
+    def _subst(a):
+        if a == '@tahoe': return script
+        return a
+    command = prefix + [runner] + map(_subst, args[1:])
+else:
+    command = prefix + [script] + args
 
 try:
     res = subprocess.call(command, env=os.environ)

diff --git a/src/allmydata/scripts/debug.py b/src/allmydata/scripts/debug.py
index 8073fe783a6e74e23237640e2a1b2d4034d87d6d..ac9b28a548f12e46f05ce8b033da81b941df45b0 100644 (file)
--- a/src/allmydata/scripts/debug.py
+++ b/src/allmydata/scripts/debug.py
@@ -846,7 +846,22 @@ Subcommands:
 
 Please run e.g. 'tahoe debug dump-share --help' for more details on each
 subcommand.
-"""
+
+Another debugging feature is that bin%stahoe allows executing an arbitrary
+"runner" command (typically an installed Python script, such as 'coverage'),
+with the Tahoe libraries on the PYTHONPATH. The runner command name is
+prefixed with '@', and any occurrences of '@tahoe' in its arguments are
+replaced by the full path to the tahoe script.
+
+For example, if 'coverage' is installed and on the PATH, you can use:
+
+    bin%stahoe @coverage run --branch @tahoe debug trial
+
+to get branch coverage for the Tahoe test suite. Or, to run python with
+the -3 option that warns about Python 3 incompatibilities:
+
+    bin%stahoe @python -3 @tahoe command [options]
+""" % (os.sep, os.sep, os.sep)
         return t
 
 subDispatch = {