get default before processing value

This ensures the default value is processed like other values. Some
type converters were adjusted to accept values that are already the
correct type.

Use parameter source instead of value to determine if argument was
supplied on the command line during completion.

Add a parameter source for values from prompt.

1 files changed, 19 insertions, 18 deletions

diff --git a/src/click/shell_completion.py b/src/click/shell_completion.py
index efefba1..9b10e25 100644
--- a/src/click/shell_completion.py
+++ b/src/click/shell_completion.py
@@ -4,6 +4,7 @@ import re
 from .core import Argument
 from .core import MultiCommand
 from .core import Option
+from .core import ParameterSource
 from .parser import split_arg_string
 from .utils import echo
 
@@ -395,29 +396,27 @@ def get_completion_class(shell):
     return _available_shells.get(shell)
 
 
-def _is_incomplete_argument(values, param):
+def _is_incomplete_argument(ctx, param):
     """Determine if the given parameter is an argument that can still
     accept values.
 
-    :param values: Dict of param names and values parsed from the
-        command line args.
+    :param ctx: Invocation context for the command represented by the
+        parsed complete args.
     :param param: Argument object being checked.
     """
     if not isinstance(param, Argument):
         return False
 
-    value = values[param.name]
-
-    if value is None:
-        return True
-
-    if param.nargs == -1:
-        return True
-
-    if isinstance(value, list) and param.nargs > 1 and len(value) < param.nargs:
-        return True
-
-    return False
+    value = ctx.params[param.name]
+    return (
+        param.nargs == -1
+        or ctx.get_parameter_source(param.name) is not ParameterSource.COMMANDLINE
+        or (
+            param.nargs > 1
+            and isinstance(value, (tuple, list))
+            and len(value) < param.nargs
+        )
+    )
 
 
 def _start_of_option(value):
@@ -523,16 +522,18 @@ def _resolve_incomplete(ctx, args, incomplete):
     if "--" not in args and _start_of_option(incomplete):
         return ctx.command, incomplete
 
+    params = ctx.command.get_params(ctx)
+
     # If the last complete arg is an option name with an incomplete
     # value, the option will provide value completions.
-    for param in ctx.command.get_params(ctx):
+    for param in params:
         if _is_incomplete_option(args, param):
             return param, incomplete
 
     # It's not an option name or value. The first argument without a
     # parsed value will provide value completions.
-    for param in ctx.command.get_params(ctx):
-        if _is_incomplete_argument(ctx.params, param):
+    for param in params:
+        if _is_incomplete_argument(ctx, param):
             return param, incomplete
 
     # There were no unparsed arguments, the command may be a group that