Fusion - the Fusion 360 Bridge

--- a/addin/AdomBridge/AdomBridge.py+++ b/addin/AdomBridge/AdomBridge.py@@ -1,114 +1,144 @@⋯ 14 unchanged lines ⋯ _custom_event = None _event_handler = None _http_thread = None+# One start-failure modal per Fusion session; repeats go to the log (#69).+_start_error_shown = False  CUSTOM_EVENT_ID = "AdomBridgeCommandEvent" ⋯ 55 unchanged lines ⋯          # Start the HTTP server on a background daemon thread         from . import http_server-        _http_thread = http_server.start(CUSTOM_EVENT_ID, _app)+        try:+            _http_thread = http_server.start(CUSTOM_EVENT_ID, _app)+        except OSError:+            # Port 8774 already bound: a SIBLING copy of this add-in is+            # serving. install() writes every known AddIns location and newer+            # Fusion builds scan more than one of them (seen live on #69:+            # FusionAddins AND API/AddIns both loaded), so a second copy+            # binding the port is normal operation, not an error the user can+            # act on. Stand down quietly; the serving copy has the job.+            adsk.core.Application.log(+                "Adom Bridge add-in: port 8774 already served by a sibling copy; this copy is standing down")+            return          # Log to the Text Commands palette (non-blocking)         adsk.core.Application.log(f"Adom Bridge add-in started (port 8774)")      except Exception:-        # Only use messageBox for errors — worth blocking to show the user-        if _ui:+        # One modal, total. The first failure is worth blocking to show the+        # user; repeats (Fusion can retry the lifecycle, and several installed+        # copies can each fail the same way) turn one broken deploy into a+        # dialog storm (#69). After the first box, log instead.+        global _start_error_shown+        if _ui and not _start_error_shown:+            _start_error_shown = True             _ui.messageBox(f"Adom Bridge failed to start:\n{traceback.format_exc()}")+        else:+            try:+                adsk.core.Application.log(f"Adom Bridge failed to start:\n{traceback.format_exc()}")+            except Exception:+                pass   def stop(context):⋯ 19 unchanged lines ⋯         _http_thread = None      except Exception:-        if _ui:-            _ui.messageBox(f"Adom Bridge stop error:\n{traceback.format_exc()}")+        # NEVER a modal from stop. Fusion re-fires the lifecycle on ordinary+        # events, so when the add-in is broken a stop-time messageBox costs the+        # user one dialog PER ACTION they take (seen live 2026-08-28, #69).+        # run() already told them once; stop failures go to the log.+        try:+            adsk.core.Application.log(f"Adom Bridge stop error:\n{traceback.format_exc()}")+        except Exception:+            pass+--- a/install_addin.py+++ b/install_addin.py@@ -1,152 +1,189 @@⋯ 77 unchanged lines ⋯                     print(f"  Removed dir: {rel}")  +def _check_relative_imports(source: Path) -> list[str]:+    """Refuse an incomplete payload BEFORE it ships. #69's failure mode: a+    payload carried the new commands/__init__.py but not the+    activity_palette.py it imports, so the sync faithfully delivered the half+    that references the missing half (and, because the sync mirrors, deleted+    any hand-restored copy as an 'extra'). Every relative import in the+    payload must resolve inside the payload; anything else bricks Fusion+    startup with a raw traceback dialog."""+    import re+    problems = []+    for py in source.rglob("*.py"):+        try:+            text = py.read_text(encoding="utf-8", errors="replace")+        except OSError:+            continue+        for m in re.finditer(r"^\s*from\s+(\.+)([\w.]+)\s+import\s", text, re.M):+            dots, mod = m.group(1), m.group(2)+            base = py.parent+            for _ in range(len(dots) - 1):+                base = base.parent+            target = base.joinpath(*mod.split("."))+            if not (target.with_suffix(".py").exists() or (target / "__init__.py").exists()):+                problems.append(f"{py.relative_to(source)}: 'from {dots}{mod} import ...' resolves to no file in the payload")+    return problems++ def find_addins_dir() -> Path | None:     """Find an existing Fusion AddIns directory, or return the first candidate."""     for candidate in TARGET_CANDIDATES:⋯ 20 unchanged lines ⋯         print(f"ERROR: Source add-in not found at {SOURCE_DIR}")         sys.exit(1) +    problems = _check_relative_imports(SOURCE_DIR)+    if problems:+        print("ERROR: refusing to install an incomplete add-in payload:")+        for p in problems:+            print(f"  {p}")+        print("Syncing this would brick Fusion startup with a traceback dialog (#69), "+              "and the mirror step would delete any hand-restored copy of the missing file. "+              "The existing installed add-in is left untouched.")+        sys.exit(1)+     print(f"Source:  {SOURCE_DIR}")     installed_to = []     for addins_dir in TARGET_CANDIDATES:⋯ 40 unchanged lines ⋯  if __name__ == "__main__":     main()+