Add Rename to the component right-click menu

Rename is offered from both the canvas and the navigation tree. Names are
checked against Sedona's Component.checkName rules (1-7 ASCII chars, a
letter first, then letters, digits or '_') and must be unique among
siblings. In file mode link paths through the old name are rewritten and
the rename is one undo step; in live mode it goes to the device via Sox
and warns if the device rejects it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sax_file.py

@@ -344,6 +344,92 @@ def save_file_as():
 MAX_NAME_LENGTH = 7     # every component name in a Sedona app observes this
 
 
+def check_component_name(name, parent=None, element=None):
+    """Why `name` cannot name a component, or None if it can.
+
+    Mirrors Sedona's Component.checkName -- 1 to 7 ASCII characters, a letter first, then
+    letters, digits or '_' -- plus the uniqueness among siblings that OfflineApp enforces.
+    `element` is the component being renamed, which may keep its own name.
+    """
+    if len(name) == 0:
+        return "The name is empty."
+    if len(name) > MAX_NAME_LENGTH:
+        return f"The name is longer than {MAX_NAME_LENGTH} characters."
+    for i, c in enumerate(name):
+        if "A" <= c <= "Z" or "a" <= c <= "z":
+            continue
+        if i == 0:
+            return "The name must start with a letter (A-Z or a-z)."
+        if "0" <= c <= "9" or c == "_":
+            continue
+        return f"'{c}' is not allowed; use only letters, digits and '_'."
+    if parent is not None:
+        for sibling in parent:
+            if sibling.tag == "comp" and sibling is not element and sibling.get("name") == name:
+                return f"'{name}' is already used by another component in the same parent."
+    return None
+
+
+def rename_component(comp_element, new_name):
+    """Renames a component and rewrites the link paths that ran through it.
+
+    Returns True when the rename happened. The name is validated here as well as in the
+    dialog, so nothing can put a name into the file that Sedona would refuse to load.
+    """
+    root = app_state.xml_root_element
+    if root is None or comp_element.tag != "comp":
+        return False
+
+    old_name = comp_element.get("name", "")
+    if new_name == old_name:
+        return False
+
+    parent = find_parent_element(root, comp_element)
+    err = check_component_name(new_name, parent, comp_element)
+    if err is not None:
+        messagebox.showwarning("Rename Component", f"'{new_name}' is not a valid name.\n\n{err}")
+        return False
+
+    if app_state.live_mode:
+        if not live_hooks.live_rename_component(comp_element, new_name):
+            live_hooks.warn_failure("Rename Component",
+                                    f"{old_name} was not renamed on the device")
+            return False
+
+    old_path = get_component_path(comp_element, root)
+    new_path = old_path[:-len(old_name)] + new_name
+
+    # Links address components by path, so every one through the old name moves with it.
+    link_changes = []
+    links_elem = root.find("links")
+    if links_elem is not None:
+        for link in links_elem:
+            if link.tag != "link":
+                continue
+            for attr in ("from", "to"):
+                ref = link.get(attr, "")
+                if ref.startswith(old_path + ".") or ref.startswith(old_path + "/"):
+                    link_changes.append((link, attr, ref, new_path + ref[len(old_path):]))
+
+    comp_element.set("name", new_name)
+    for link, attr, _, new_ref in link_changes:
+        link.set(attr, new_ref)
+
+    if not app_state.live_mode:
+        undo.push(undo.RenameComponentCommand(
+            comp_element, old_name, new_name, link_changes,
+            label=f"rename {old_name} to {new_name}"
+        ))
+
+    app_state.mark_dirty()
+    refresh_treeview_from_dom(root)
+    wiresheet.render_current_sheet()
+
+    where = " on the device" if app_state.live_mode else ""
+    app_state.set_status(f"{old_name} renamed to {new_name}{where}.")
+    return True
+
+
 def allocate_component_id():
     """Lowest unused id, matching how this app's ids are dense with no gaps."""
     used = set()