Minor argparse improvement.

lib/spack/external/argparse.py

@@ -108,6 +108,8 @@
 import sys as _sys
 import textwrap as _textwrap
 
+from llnl.util.tty.colify import colified
+
 from gettext import gettext as _
 
 try:
@@ -2285,8 +2287,8 @@ def _get_value(self, action, arg_string):
     def _check_value(self, action, value):
         # converted value must be one of the choices (if specified)
         if action.choices is not None and value not in action.choices:
-            tup = value, ', '.join(map(repr, action.choices))
-            msg = _('invalid choice: %r (choose from %s)') % tup
+            cols = colified(sorted(action.choices), indent=4, tty=True)
+            msg = _('invalid choice: %r choose from:\n%s') % (value, cols)
             raise ArgumentError(action, msg)
 
     # =======================

lib/spack/llnl/util/tty/colify.py

@@ -37,9 +37,11 @@
 import fcntl
 import termios
 import struct
+from StringIO import StringIO
 
 from llnl.util.tty import terminal_size
 
+
 class ColumnConfig:
     def __init__(self, cols):
         self.cols = cols
@@ -102,16 +104,18 @@ def colify(elts, **options):
     output       = options.get("output", sys.stdout)
     indent       = options.get("indent", 0)
     padding      = options.get("padding", 2)
+    tty          = options.get('tty', None)
 
     # elts needs to be an array of strings so we can count the elements
     elts = [str(elt) for elt in elts]
     if not elts:
         return
 
-    if not isatty(output):
-        for elt in elts:
-            output.write("%s\n" % elt)
-        return
+    if not tty:
+        if tty is False or not isatty(output):
+            for elt in elts:
+                output.write("%s\n" % elt)
+            return
 
     console_cols = options.get("cols", None)
     if not console_cols:
@@ -147,6 +151,15 @@ def colify(elts, **options):
             cols -= 1
 
 
+def colified(elts, **options):
+    """Invokes the colify() function but returns the result as a string
+       instead of writing it to an output string."""
+    sio = StringIO()
+    options['output'] = sio
+    colify(elts, **options)
+    return sio.getvalue()
+
+
 if __name__ == "__main__":
     import optparse