test(#3635): add profile-switcher source-of-truth invariant (rebased from #3639) (#3644)

Test-only. Adds TestProfileSwitcherSourceOfTruthInvariant generalizing the #3635
fix so the chip + dropdown can't re-split their source of truth (both must read
S.activeProfile). Rebased onto current master — the original #3639 branch was
stacked on the pre-squash #3637 and would have reverted ~5 shipped releases
(IF/IG/IH) if merged as-is; this carries ONLY the +74-line test delta.

Co-authored-by: nesquena-hermes <[email protected]>
Co-authored-by: nesquena <nesquena@users.noreply.github.com>

tests/test_issue3635_profile_chip_active.py

@@ -89,3 +89,77 @@ class TestIssue3635ProfileChipActive:
             "expected both syncTopbar chip-label setters to read "
             "S.activeProfile||'default'; found: " + str(setters)
         )
+
+
+def _panels_js() -> str:
+    return (Path(__file__).parent.parent / "static" / "panels.js").read_text(encoding="utf-8")
+
+
+def _render_profile_dropdown_body(src: str) -> str:
+    """Return the source of renderProfileDropdown()."""
+    start = src.find("function renderProfileDropdown(")
+    assert start != -1, "renderProfileDropdown not found in panels.js"
+    i = src.find("{", start)
+    depth = 0
+    for j in range(i, len(src)):
+        if src[j] == "{":
+            depth += 1
+        elif src[j] == "}":
+            depth -= 1
+            if depth == 0:
+                return src[start : j + 1]
+    raise AssertionError("could not find end of renderProfileDropdown()")
+
+
+class TestProfileSwitcherSourceOfTruthInvariant:
+    """Standing invariant guard (generalizes #3635).
+
+    The profile chip (the switcher trigger, in syncTopbar()/ui.js) and the
+    profile dropdown's active/checkmark row (renderProfileDropdown()/panels.js)
+    are two renderings of the SAME thing — "which profile is active." They must
+    resolve from the same source of truth (S.activeProfile). #3331 broke this by
+    pointing the chip at S.session.profile while the dropdown still used
+    S.activeProfile, so the switcher trigger and the menu it opens disagreed
+    (#3635). This invariant fails fast if any future change re-splits them.
+    """
+
+    def test_chip_keys_on_active_profile(self):
+        body = _sync_topbar_body(_ui_js())
+        # Every profileChipLabel.textContent assignment must read S.activeProfile.
+        assignments = re.findall(r"profileChipLabel'\);[\s\S]{0,120}?\.textContent=([^;]+);", body)
+        assert assignments, "no profileChipLabel assignment found in syncTopbar()"
+        for expr in assignments:
+            assert "S.activeProfile" in expr and "S.session.profile" not in expr, (
+                "profile chip (switcher trigger) must resolve from S.activeProfile, "
+                "not the loaded session's profile: " + expr.strip()
+            )
+
+    def test_dropdown_active_row_keys_on_active_profile(self):
+        body = _render_profile_dropdown_body(_panels_js())
+        # The dropdown's active row is computed into `const active = ...`.
+        m = re.search(r"const active\s*=\s*([\s\S]*?);", body)
+        assert m, "could not find the `const active =` computation in renderProfileDropdown()"
+        expr = m.group(1)
+        assert "S.activeProfile" in expr, (
+            "dropdown active-row must resolve from S.activeProfile so it agrees "
+            "with the chip (switcher source-of-truth invariant): " + expr.strip()
+        )
+
+    def test_chip_and_dropdown_share_source_of_truth(self):
+        """The chip and the dropdown active-row must BOTH key on S.activeProfile.
+
+        This is the cross-file invariant that #3635 violated: a passing version
+        of this test means the switcher trigger and the menu it opens can never
+        again silently disagree about which profile is active.
+        """
+        chip_body = _sync_topbar_body(_ui_js())
+        dd_body = _render_profile_dropdown_body(_panels_js())
+        chip_ok = "S.activeProfile" in chip_body and \
+            "(S.session&&S.session.profile)||S.activeProfile" not in chip_body
+        dd_ok = "S.activeProfile" in dd_body
+        assert chip_ok and dd_ok, (
+            "profile chip (ui.js syncTopbar) and dropdown active-row "
+            "(panels.js renderProfileDropdown) must share S.activeProfile as the "
+            "single source of truth for 'active profile' (#3635). "
+            f"chip_ok={chip_ok} dd_ok={dd_ok}"
+        )