refactor(ui): consolidate MainForm busy guards

Moves every MainForm busy predicate into MainForm.Guards.cs, built on
IsJobRunning, ViewsOf, IsPlateWorkBusy and IsNestFillBusy. Auto Nest,
Validate and Post share TryBeginPlateCommand; Clamps, Automatic Cutoffs
and Plan Cutting reuse the shared predicates. The deliberate variants
(Expand Spacing ignores busy actions; the report guard adds database
saves) keep their names and remain pinned by characterization tests.
NavigationEnableCheck now takes the lockout flag instead of
SetNestingLockout repeating its logic.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

OpenNest/Forms/MainForm.File.cs

@@ -413,16 +413,6 @@ namespace OpenNest.Forms
             ReportSuccess(destination);
         }
 
-        /// <summary>
-        /// True while any operation could mutate nests or hold their plate views: whole-job
-        /// nesting, an open progress window (a closed one can still await its commit), or a
-        /// background database save serializing the live nest.
-        /// </summary>
-        private bool IsNestJobBusy() =>
-            nestingInProgress
-            || Application.OpenForms.OfType<NestProgressForm>().Any()
-            || databaseSaveInProgress;
-
         /// <summary>Returns the chosen path, or null on cancel. Overwrite consent is the dialog prompt.</summary>
         internal virtual string ShowReportSaveDialog(string suggestedFileName)
         {

OpenNest/Forms/MainForm.Guards.cs

@@ -0,0 +1,80 @@
+using System.Linq;
+using System.Windows.Forms;
+using OpenNest.Actions;
+using OpenNest.Controls;
+
+namespace OpenNest.Forms
+{
+    public partial class MainForm
+    {
+        /// <summary>
+        /// True while whole-job nesting runs or a progress window is open; a closed
+        /// progress window can still have a fill awaiting its final commit.
+        /// </summary>
+        private bool IsJobRunning =>
+            nestingInProgress || Application.OpenForms.OfType<NestProgressForm>().Any();
+
+        private PlateView[] ViewsOf(Nest nest) =>
+            MdiChildren
+                .OfType<EditNestForm>()
+                .Where(form => ReferenceEquals(form.Nest, nest))
+                .Select(form => form.PlateView)
+                .ToArray();
+
+        /// <summary>
+        /// The guard for plate commands: a running job, or any of <paramref name="views"/>
+        /// filling or holding a busy current action.
+        /// </summary>
+        private bool IsPlateWorkBusy(PlateView[] views) =>
+            IsJobRunning
+            || views.Any(v => v.IsFillInProgress || v.Actions.CurrentAction?.IsBusy() == true);
+
+        /// <summary>
+        /// A running job or a fill on any view of <paramref name="nest"/>; a busy current
+        /// action does not count.
+        /// </summary>
+        private bool IsNestFillBusy(Nest nest) =>
+            IsJobRunning || ViewsOf(nest).Any(v => v.IsFillInProgress);
+
+        /// <summary>
+        /// True while a nest run or fill may be reading <paramref name="nest"/>'s clamps.
+        /// Clamps feed nesting and validation: never change them under a running operation.
+        /// </summary>
+        private bool ClampsInUse(Nest nest) => IsNestFillBusy(nest);
+
+        /// <summary>
+        /// True while whole-job nesting or a fill on any view of the nest can still
+        /// change its plates. Unlike the other plate commands' guard, a busy current
+        /// action does not count: ActionSelect reports busy whenever parts are
+        /// selected, and Expand Spacing needs a selection.
+        /// </summary>
+        internal bool IsExpandSpacingBusy(EditNestForm editForm) => IsNestFillBusy(editForm.Nest);
+
+        internal bool IsCuttingPlanBusy(PlateView[] views) => IsPlateWorkBusy(views);
+
+        /// <summary>
+        /// True while any operation could mutate nests or hold their plate views: whole-job
+        /// nesting, an open progress window (a closed one can still await its commit), or a
+        /// background database save serializing the live nest.
+        /// </summary>
+        private bool IsNestJobBusy() => IsJobRunning || databaseSaveInProgress;
+
+        /// <summary>
+        /// Refuses with <paramref name="message"/> while plate work on <paramref name="nest"/>
+        /// is busy; otherwise returns every view of the nest to selection and returns true.
+        /// </summary>
+        private bool TryBeginPlateCommand(Nest nest, string message, string caption)
+        {
+            var views = ViewsOf(nest);
+            if (IsPlateWorkBusy(views))
+            {
+                MessageBox.Show(this, message, caption, MessageBoxButtons.OK, MessageBoxIcon.Information);
+                return false;
+            }
+
+            foreach (var view in views)
+                view.SetAction(typeof(ActionSelect));
+            return true;
+        }
+    }
+}

OpenNest/Forms/MainForm.Nest.cs

@@ -6,9 +6,7 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
-using OpenNest.Actions;
 using OpenNest.Collections;
-using OpenNest.Controls;
 using OpenNest.Diagnostics;
 using OpenNest.Engine;
 using OpenNest.Engine.Fill;
@@ -64,22 +62,6 @@ namespace OpenNest.Forms
             activeForm.ShowNestInfoEditor();
         }
 
-        private PlateView[] ViewsOf(Nest nest) =>
-            MdiChildren
-                .OfType<EditNestForm>()
-                .Where(form => ReferenceEquals(form.Nest, nest))
-                .Select(form => form.PlateView)
-                .ToArray();
-
-        /// <summary>
-        /// True while a nest run or fill may be reading <paramref name="nest"/>'s clamps.
-        /// Clamps feed nesting and validation: never change them under a running operation.
-        /// </summary>
-        private bool ClampsInUse(Nest nest) =>
-            nestingInProgress
-            || Application.OpenForms.OfType<NestProgressForm>().Any()
-            || ViewsOf(nest).Any(v => v.IsFillInProgress);
-
         private void Clamps_Click(object sender, EventArgs e)
         {
             var editForm = activeForm;
@@ -88,7 +70,7 @@ namespace OpenNest.Forms
 
             var nest = editForm.Nest;
             var views = ViewsOf(nest);
-            if (ClampsInUse(nest) || views.Any(v => v.Actions.CurrentAction?.IsBusy() == true))
+            if (IsPlateWorkBusy(views))
             {
                 MessageBox.Show(
                     this,
@@ -193,17 +175,9 @@ namespace OpenNest.Forms
             var target = activeForm;
             if (target == null || target.IsDisposed || target.PlateView.Plate == null)
                 return;
-            var views = MdiChildren.OfType<EditNestForm>()
-                .Where(f => ReferenceEquals(f.Nest, target.Nest)).Select(f => f.PlateView).ToArray();
-            if (nestingInProgress || Application.OpenForms.OfType<NestProgressForm>().Any()
-                || views.Any(v => v.IsFillInProgress || v.Actions.CurrentAction?.IsBusy() == true))
-            {
-                MessageBox.Show(this, "Finish or cancel the current plate operation before Auto Nest.",
-                    "Auto Nest", MessageBoxButtons.OK, MessageBoxIcon.Information);
+            if (!TryBeginPlateCommand(target.Nest,
+                    "Finish or cancel the current plate operation before Auto Nest.", "Auto Nest"))
                 return;
-            }
-            foreach (var view in views)
-                view.SetAction(typeof(ActionSelect));
 
             using var form = new AutoNestForm(target.Nest);
             if (target.Nest.PlateOptions.Count > 0)
@@ -356,19 +330,10 @@ namespace OpenNest.Forms
             if (editForm == null)
                 return;
 
-            var views = MdiChildren.OfType<EditNestForm>()
-                .Where(form => ReferenceEquals(form.Nest, editForm.Nest))
-                .Select(form => form.PlateView).ToArray();
-            if (nestingInProgress || Application.OpenForms.OfType<NestProgressForm>().Any()
-                || views.Any(view => view.IsFillInProgress || view.Actions.CurrentAction?.IsBusy() == true))
-            {
-                MessageBox.Show(this, "Finish or cancel the current nesting or plate action before validating.",
-                    "Validate Nest", MessageBoxButtons.OK, MessageBoxIcon.Information);
+            if (!TryBeginPlateCommand(editForm.Nest,
+                    "Finish or cancel the current nesting or plate action before validating.", "Validate Nest"))
                 return;
-            }
 
-            foreach (var view in views)
-                view.SetAction(typeof(ActionSelect));
             editForm.OpenValidationInspection();
         }
 
@@ -389,19 +354,11 @@ namespace OpenNest.Forms
                     "Verify Nest Before Posting", MessageBoxButtons.OK, MessageBoxIcon.Information);
                 return;
             }
-            var views = MdiChildren.OfType<EditNestForm>()
-                .Where(form => ReferenceEquals(form.Nest, editForm.Nest))
-                .Select(form => form.PlateView).ToArray();
-            if (nestingInProgress || Application.OpenForms.OfType<NestProgressForm>().Any()
-                || views.Any(view => view.IsFillInProgress || view.Actions.CurrentAction?.IsBusy() == true))
-            {
-                MessageBox.Show(this, "Finish or cancel the current nesting or plate action before posting.",
-                    "Verify Nest Before Posting", MessageBoxButtons.OK, MessageBoxIcon.Information);
+            if (!TryBeginPlateCommand(editForm.Nest,
+                    "Finish or cancel the current nesting or plate action before posting.",
+                    "Verify Nest Before Posting"))
                 return;
-            }
 
-            foreach (var view in views)
-                view.SetAction(typeof(ActionSelect));
             var nest = editForm.Nest;
 
             if (postProcessor is IPostProcessorNestAware nestAware)

OpenNest/Forms/MainForm.Plate.cs

@@ -2,7 +2,6 @@ using System;
 using System.Linq;
 using System.Windows.Forms;
 using OpenNest.Actions;
-using OpenNest.Controls;
 
 namespace OpenNest.Forms
 {
@@ -119,12 +118,8 @@ namespace OpenNest.Forms
                 return;
 
             var nest = editForm.Nest;
-            var views = MdiChildren.OfType<EditNestForm>()
-                .Where(form => ReferenceEquals(form.Nest, nest))
-                .Select(form => form.PlateView).ToArray();
-            // A closed progress window can still have a fill awaiting completion/commit.
-            bool IsBusy() => nestingInProgress || Application.OpenForms.OfType<NestProgressForm>().Any()
-                || views.Any(v => v.IsFillInProgress || v.Actions.CurrentAction?.IsBusy() == true);
+            var views = ViewsOf(nest);
+            bool IsBusy() => IsPlateWorkBusy(views);
             if (IsBusy())
             {
                 MessageBox.Show(this, "Finish or cancel the current nesting or plate action first.",
@@ -157,10 +152,6 @@ namespace OpenNest.Forms
 
         private void NestPlanCutting_Click(object sender, EventArgs e) => ShowCuttingPlan(allPlates: true);
 
-        internal bool IsCuttingPlanBusy(PlateView[] views) => nestingInProgress
-            || Application.OpenForms.OfType<NestProgressForm>().Any()
-            || views.Any(v => v.IsFillInProgress || v.Actions.CurrentAction?.IsBusy() == true);
-
         // Native tests capture this notice without opening a modal dialog in session zero.
         internal System.Action<string, string> CuttingPlanNotice { get; set; }
 
@@ -181,10 +172,7 @@ namespace OpenNest.Forms
                 return;
 
             var nest = editForm.Nest;
-            var views = MdiChildren.OfType<EditNestForm>()
-                .Where(form => ReferenceEquals(form.Nest, nest))
-                .Select(form => form.PlateView).ToArray();
-            // A closed progress window can still have a fill awaiting completion/commit.
+            var views = ViewsOf(nest);
             if (IsCuttingPlanBusy(views))
             {
                 ShowCuttingPlanNotice("Finish or cancel the current nesting or plate action first.", "Plan Cutting");

OpenNest/Forms/MainForm.Status.cs

@@ -37,49 +37,25 @@ namespace OpenNest.Forms
             toolStripMenuItem15.Visible = hasValue;
         }
 
-        private void NavigationEnableCheck()
+        private void NavigationEnableCheck(bool locked = false)
         {
-            if (activeForm == null)
-            {
-                mnuNestPreviousPlate.Enabled = false;
-                mnuNestNextPlate.Enabled = false;
-                mnuNestFirstPlate.Enabled = false;
-                mnuNestLastPlate.Enabled = false;
-            }
-            else
-            {
-                mnuNestPreviousPlate.Enabled = !activeForm.PlateManager.IsFirst;
-                mnuNestNextPlate.Enabled = !activeForm.PlateManager.IsLast;
-                mnuNestFirstPlate.Enabled =
-                    activeForm.PlateManager.Count > 0 && !activeForm.PlateManager.IsFirst;
-                mnuNestLastPlate.Enabled =
-                    activeForm.PlateManager.Count > 0 && !activeForm.PlateManager.IsLast;
-            }
+            var plates = locked ? null : activeForm?.PlateManager;
+            var hasPlates = plates != null && plates.Count > 0;
+
+            mnuNestPreviousPlate.Enabled = plates != null && !plates.IsFirst;
+            mnuNestNextPlate.Enabled = plates != null && !plates.IsLast;
+            mnuNestFirstPlate.Enabled = hasPlates && !plates.IsFirst;
+            mnuNestLastPlate.Enabled = hasPlates && !plates.IsLast;
         }
 
         private void SetNestingLockout(bool locked)
         {
             nestingInProgress = locked;
 
-            // Disable nesting-related menus while running
+            // Disable nesting-related menus and plate navigation while running
             mnuNest.Enabled = !locked;
             mnuPlate.Enabled = !locked;
-
-            // Lock plate navigation
-            mnuNestPreviousPlate.Enabled =
-                !locked && activeForm != null && !activeForm.PlateManager.IsFirst;
-            mnuNestNextPlate.Enabled =
-                !locked && activeForm != null && !activeForm.PlateManager.IsLast;
-            mnuNestFirstPlate.Enabled =
-                !locked
-                && activeForm != null
-                && activeForm.PlateManager.Count > 0
-                && !activeForm.PlateManager.IsFirst;
-            mnuNestLastPlate.Enabled =
-                !locked
-                && activeForm != null
-                && activeForm.PlateManager.Count > 0
-                && !activeForm.PlateManager.IsLast;
+            NavigationEnableCheck(locked);
         }
 
         private void UpdateLocationStatus()

OpenNest/Forms/MainForm.Tools.cs

@@ -1,6 +1,5 @@
 using System;
 using System.IO;
-using System.Linq;
 using System.Windows.Forms;
 using OpenNest.Actions;
 using OpenNest.Data;
@@ -81,20 +80,6 @@ namespace OpenNest.Forms
                 ShowExpandSpacingNotice("Select at least two parts on the plate to expand.");
         }
 
-        /// <summary>
-        /// True while whole-job nesting or a fill on any view of the nest can still
-        /// change its plates. Unlike the other plate commands' guard, a busy current
-        /// action does not count: ActionSelect reports busy whenever parts are
-        /// selected, and Expand Spacing needs a selection.
-        /// </summary>
-        internal bool IsExpandSpacingBusy(EditNestForm editForm) =>
-            nestingInProgress
-            || Application.OpenForms.OfType<NestProgressForm>().Any()
-            || MdiChildren
-                .OfType<EditNestForm>()
-                .Where(form => ReferenceEquals(form.Nest, editForm.Nest))
-                .Any(form => form.PlateView.IsFillInProgress);
-
         // Native tests capture this notice without opening a modal dialog in session zero.
         internal System.Action<string> ExpandSpacingNotice { get; set; }
 

OpenNest/OpenNest.csproj

@@ -44,7 +44,7 @@
       <DependentUpon>Settings.settings</DependentUpon>
       <DesignTimeSharedInput>True</DesignTimeSharedInput>
     </Compile>
-    <Compile Update="Forms\MainForm.File.cs;Forms\MainForm.Nest.cs;Forms\MainForm.Plate.cs;Forms\MainForm.Status.cs;Forms\MainForm.Tools.cs;Forms\MainForm.View.cs">
+    <Compile Update="Forms\MainForm.File.cs;Forms\MainForm.Guards.cs;Forms\MainForm.Nest.cs;Forms\MainForm.Plate.cs;Forms\MainForm.Status.cs;Forms\MainForm.Tools.cs;Forms\MainForm.View.cs">
       <DependentUpon>MainForm.cs</DependentUpon>
       <SubType>Code</SubType>
     </Compile>