Fix version visualization and add verbose logging

Raise an exception for unparsable versions and aggregate visualization output in a list before printing. Add a verbose logging option to the `show_bump` command for detailed logging control.

bumpversion/cli.py

@@ -575,8 +575,17 @@ def sample_config(prompt: bool, destination: str) -> None:
     help="Config file to read most of the variables from.",
 )
 @click.option("--ascii", is_flag=True, help="Use ASCII characters only.")
-def show_bump(version: str, config_file: Optional[str], ascii: bool) -> None:
+@click.option(
+    "-v",
+    "--verbose",
+    count=True,
+    required=False,
+    envvar="BUMPVERSION_VERBOSE",
+    help="Print verbose logging to stderr. Can specify several times for more verbosity.",
+)
+def show_bump(version: str, config_file: Optional[str], ascii: bool, verbose: int) -> None:
     """Show the possible versions resulting from the bump subcommand."""
+    setup_logging(verbose)
     found_config_file = find_config_file(config_file)
     config = get_configuration(found_config_file)
     if not version:

bumpversion/visualize.py

@@ -111,6 +111,8 @@ def filter_version_parts(config: Config) -> List[str]:
 def visualize(config: Config, version_str: str, box_style: str = "light") -> None:
     """Output a visualization of the bump-my-version bump process."""
     version = config.version_config.parse(version_str)
+    if version is None:
+        raise BumpVersionError(f"Unable to parse version {version_str}")
     version_parts = filter_version_parts(config)
     num_parts = len(version_parts)
 
@@ -120,7 +122,7 @@ def visualize(config: Config, version_str: str, box_style: str = "light") -> Non
     version_lead = lead_string(version_str, border)
     blank_lead = lead_string(version_str, border, blank=True)
     version_part_length = max(len(part) for part in version_parts)
-
+    lines = []
     for i, part in enumerate(version_parts):
         line = [version_lead] if i == 0 else [blank_lead]
 
@@ -135,4 +137,5 @@ def visualize(config: Config, version_str: str, box_style: str = "light") -> Non
         line.append(connection_str(border, has_next=has_next, has_previous=has_previous))
         line.append(labeled_line(part, border, version_part_length))
         line.append(next_version_str)
-        print_info("".join(line))
+        lines.append("".join(line))
+    print_info("\n".join(lines))