[Detail Bug] KNX GUI: Entering/pasting Unicode superscript/subscript digits in Individual Address input crashes the app

Detail Bug Report

https://app.detail.dev/org_62aa40f5-2c23-4914-a665-3bb2068af20e/bugs/bug_62302d4f-6afe-4638-9211-0eb4b8fb1652

Introduced in #26 by @kewde on Sep 6, 2026

Summary

• Context: render_bounded_numeric_segment in apps/knx-gui/src/knx_gui/widgets/segmented_input.py renders the three dotted Individual Address segments (area / line / device) in the Configure panel - the widget's sole production caller (ConfigurePanel.render, apps/knx-gui/src/knx_gui/plugins/project/ui/configure.py:127-142).
• Bug: Its callback_edit cleanup filters the live buffer with c.isdigit() and feeds the result straight into int(...). str.isdigit() returns True for Unicode superscripts/subscripts (² U+00B2, ³ U+00B3, ¹ U+00B9, ₂ U+2082, …) that int() rejects, so the callback raises ValueError.
• Actual vs. expected: The widget's docstring (segmented_input.py:30-36) promises "any non-digit character… is corrected live". Typing or pasting ² is promised to be silently cleaned up; instead it throws an unhandled Python ValueError out of the per-frame ImGui callback.
• Impact: The widget raises mid-frame; imgui.end() and the rest of ConfigurePanel.render are skipped; on the next frame Dear ImGui's Begin() trips IM_ASSERT("Missing End()"); std::terminate is called, the process dies with SIGSEGV (exit code 139). The user loses the entire application from a single keystroke/paste of a superscript "digit".

Code with Bug

    def _filter(data: imgui.InputTextCallbackData) -> int:
        if data.event_flag == imgui.InputTextFlags_.callback_edit:
            text = str(data.buf)[: data.buf_text_len]
            digits = "".join(c for c in text if c.isdigit())[:max_len]   # <-- BUG 🔴 isdigit() admits superscripts/subscripts int() cannot parse
            clamped = str(min(int(digits), max_value)) if digits else ""  # <-- BUG 🔴 raises ValueError for e.g. digits == '²'
            if clamped != text:
                data.delete_chars(0, data.buf_text_len)
                if clamped:
                    data.insert_chars(0, clamped)
            return 0
        # callback_char_filter: only "." needs special handling here - every
        # other non-digit character, excess length and an out-of-range value
        # are all cleaned up by the callback_edit pass above.
        if chr(data.event_char) == ".":
            advance[0] = True
            return 1
        return 0

Explanation

• callback_char_filter only rejects "."; it accepts all other characters (including ²/₂) into the input buffer.
• On the subsequent callback_edit, the buffer is “cleaned” using c.isdigit(). For Unicode superscripts/subscripts, isdigit() is True, so they survive filtering.
• The filtered string is then passed to int(digits), which does not accept those Unicode numerals, raising ValueError.
• The exception is unhandled in the production call path (ConfigurePanel.render), so the frame exits without matching imgui.begin()/end(). On the next frame ImGui asserts "Missing End()" and terminates the process.

Recommended Fix

Filter on ASCII decimal digits explicitly:

            digits = "".join(c for c in text if c in "0123456789")[:max_len]

(equivalently c.isascii() and c.isdecimal()).

History

This bug was introduced in commit 1ab42e3b. That commit added the segmented_input.py widget wholesale (PR #26, "segmented Individual Address input, Area/Line/Device bounded"), replacing the old free-form individual-address text field with three bounded numeric segments.

Start in apps/knx-gui/src/knx_gui/widgets/segmented_input.py, especially render_bounded_numeric_segment and its callback_edit cleanup, then review its sole caller in apps/knx-gui/src/knx_gui/plugins/project/ui/configure.py:127-142. Verify that entering or pasting superscript/subscript digits no longer raises ValueError, leaves the input safely cleaned, or breaks ConfigurePanel.render.