feat: a repaired hole keeps a fainter band, so a report is not a false accusation

src/ui.cpp

@@ -10502,7 +10502,10 @@ gboolean color_probe(gpointer user) {
 /// `bands`. The first is the state of the *data* rather than of a counter: a reservation writes
 /// placeholders and a backfill repairs them, and the two counters agreeing proves only that the
 /// same number of slots was written and read, not that the right ones were. The second asserts the
-/// trigger never latched inside a reserved span. The third asserts the band reached the plot.
+/// trigger never latched inside a reserved span. The third asserts the band reached the plot, and
+/// splits it by state: a hole whose late packets have all arrived keeps its band in the fainter
+/// tint, so `bands_repaired` is how a reading tells a window that is *missing* data from one that
+/// merely *was*.
 gboolean reseq_probe(gpointer user) {
   App* a = static_cast<App*>(user);
   if (a->window == nullptr) return G_SOURCE_REMOVE;
@@ -10543,22 +10546,29 @@ gboolean reseq_probe(gpointer user) {
     }
   }
   // The shading as the plot actually holds it, read off row 0 after the frame published it. Every
-  // row carries the same spans, so one row is the whole answer.
+  // row carries the same spans, so one row is the whole answer. Split by state because the two
+  // mean different things: `bands` is what the window is reporting and `bands_repaired` how much
+  // of that report is historical, so `bands == bands_repaired` with `nan_slots=0` is a healthy
+  // reading and not the contradiction it would be if the band had one state.
   std::size_t bands = 0;
+  std::size_t bands_repaired = 0;
   if (a->rows->row_count() > 0 && a->rows->row(0).plot != nullptr) {
-    bands = a->rows->row(0).plot->invalid_spans().size();
+    for (const plot::InvalidSpan& span : a->rows->row(0).plot->invalid_spans()) {
+      ++bands;
+      if (span.repaired) ++bands_repaired;
+    }
   }
   std::fprintf(stderr,
                "[reseq-probe] reseq=%llu late=%llu stale=%llu holes=%llu hole_slots=%llu "
-               "backfilled=%llu open_holes=%zu bands=%zu nan_slots=%llu scanned=%llu "
-               "trigger_in_hole=%d\n",
+               "backfilled=%llu open_holes=%zu bands=%zu bands_repaired=%zu nan_slots=%llu "
+               "scanned=%llu trigger_in_hole=%d\n",
                static_cast<unsigned long long>(m.stats().resequenced.load()),
                static_cast<unsigned long long>(m.stats().late.load()),
                static_cast<unsigned long long>(m.stats().stale.load()),
                static_cast<unsigned long long>(m.stats().holes.load()),
                static_cast<unsigned long long>(m.stats().hole_slots.load()),
                static_cast<unsigned long long>(m.stats().backfilled.load()), open_holes, bands,
-               static_cast<unsigned long long>(nan_slots),
+               bands_repaired, static_cast<unsigned long long>(nan_slots),
                static_cast<unsigned long long>(scanned), trigger_in_hole);
   std::fflush(stderr);
   return G_SOURCE_REMOVE;