Inline state updates left the page stale after the server
recalculated the active due date. Snapshots now set values
through Alpine's model so saves actually fire.

Assisted-by: Claude Opus 4.6 via Claude Code

diff --git a/lib/ketchup/snapshots.rb b/lib/ketchup/snapshots.rb
index 05c29a8..7ca63e9 100644
--- a/lib/ketchup/snapshots.rb
+++ b/lib/ketchup/snapshots.rb
@@ -73,7 +73,7 @@ module Ketchup
         baseline_file.close
         current_file.close
 
-        `diff -u #{baseline_file.path} #{current_file.path}`.lines.drop(2).filter_map do |line|
+        `diff -U9999 #{baseline_file.path} #{current_file.path}`.lines.drop(2).filter_map do |line|
           name = line[1..].chomp
           next if name.empty?
           case line[0]
@@ -141,6 +141,10 @@ module Ketchup
       #   series in editing mode
       #   series with task history
       #   adding a note to a completed task
+      #   editing an older completed date
+      #   after saving the older completed date
+      #   editing the most recent completed date
+      #   after saving (active due date updates)
       #
       # User settings (/users/:id)
       #   viewing
@@ -203,6 +207,34 @@ module Ketchup
         textarea.evaluate('this.dispatchEvent(new Event("input", { bubbles: true }))')
         entries << snap("series-add-note", selector: ".main-column")
 
+        # Edit an older completed date (not the most recent) — active due date should not change
+        entries << snap("series-edit-old-date", selector: ".main-column") do
+          goto "#{@base}/series/#{series_with_history.id}"
+          wait_for(".task-history")
+          @browser.execute('document.querySelectorAll(".task-history-date")[1].click()')
+          wait_for(".task-history-date-input")
+        end
+
+        old_date = (Date.today - 30).strftime("%Y-%m-%d")
+        set_date_and_save(".task-history-date-input", old_date)
+        entries << snap("series-old-date-saved", selector: ".main-column") do
+          goto "#{@base}/series/#{series_with_history.id}"
+          wait_for(".task-history")
+        end
+
+        # Edit the most recent completed date — active due date should update
+        entries << snap("series-edit-latest-date", selector: ".main-column") do
+          wait_for(".task-history-date").click
+          wait_for(".task-history-date-input")
+        end
+
+        latest_date = (Date.today - 14).strftime("%Y-%m-%d")
+        set_date_and_save(".task-history-date-input", latest_date)
+        entries << snap("series-latest-date-saved", selector: ".main-column") do
+          goto "#{@base}/series/#{series_with_history.id}"
+          wait_for(".task-history")
+        end
+
         # ── User settings ──
 
         user = User.first(login: "snapshot@example.com")
@@ -314,6 +346,32 @@ module Ketchup
         unit_select.select(interval_unit)
       end
 
+      # Set a date input's value via Alpine's x-model (dispatches input
+      # event so the reactive model updates) then blur to trigger save().
+      # Waits for the page to reload before returning.
+      def set_date_and_save(selector, date)
+        @browser.execute("document.body.dataset.snapshotMarker = '1'")
+        @browser.execute(<<~JS)
+          var input = document.querySelector('#{selector}');
+          var nativeInputValueSetter = Object.getOwnPropertyDescriptor(window.HTMLInputElement.prototype, 'value').set;
+          nativeInputValueSetter.call(input, '#{date}');
+          input.dispatchEvent(new Event('input', { bubbles: true }));
+          input.dispatchEvent(new Event('change', { bubbles: true }));
+          input.dispatchEvent(new Event('blur', { bubbles: true }));
+        JS
+        wait_for_reload
+      end
+
+      def wait_for_reload(timeout: 5)
+        start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        loop do
+          break unless @browser.evaluate("document.body.dataset.snapshotMarker")
+          elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - start
+          raise Ferrum::TimeoutError, "waiting for page reload" if elapsed > timeout
+          sleep 0.05
+        end
+      end
+
       # Find a series that has both noted and un-noted completed tasks,
       # so the history screenshot shows both states.
       def find_series_with_mixed_history
diff --git a/public/js/app.js b/public/js/app.js
index a1b789d..47f4c48 100644
--- a/public/js/app.js
+++ b/public/js/app.js
@@ -233,12 +233,7 @@ document.addEventListener("alpine:init", () => {
         method: "PATCH",
         headers: { "Content-Type": "application/json" },
         body: JSON.stringify({ completed_at: this.completedDate }),
-      }).then((r) => {
-        if (r.ok) {
-          initialDate = this.completedDate
-          this.editingDate = false
-        }
-      })
+      }).then(() => location.reload())
     },
   }))