From 2defe9ff95016fd72e9a16b4a8fa8b8d0ec5a45f Mon Sep 17 00:00:00 2001
From: Martin Duffy <martin.duffy@kitware.com>
Date: Thu, 12 May 2022 16:43:15 -0400
Subject: ccmake: Fix crash when deleting all cache entries

Prevents crash when deleting all cache entries.
Additionally, if advanced entries are hidden, no longer show the first advanced
entry when deleting all visible entries.

Fixes: #23499
---
 Source/CursesDialog/cmCursesMainForm.cxx | 19 ++++++++++---------
 Source/CursesDialog/cmCursesMainForm.h   |  1 +
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Source/CursesDialog/cmCursesMainForm.cxx b/Source/CursesDialog/cmCursesMainForm.cxx
index cd0a4bd..3e254e0 100644
--- a/Source/CursesDialog/cmCursesMainForm.cxx
+++ b/Source/CursesDialog/cmCursesMainForm.cxx
@@ -93,13 +93,13 @@ void cmCursesMainForm::InitializeUI()
 
   int entrywidth = this->InitialWidth - 35;
 
-  if (count == 0) {
-    // If cache is empty, display a label saying so and a
-    // dummy entry widget (does not respond to input)
-    cmCursesCacheEntryComposite comp("EMPTY CACHE", 30, 30);
-    comp.Entry = cm::make_unique<cmCursesDummyWidget>(1, 1, 1, 1);
-    newEntries.emplace_back(std::move(comp));
-  } else {
+  // Add a label to display when cache is empty
+  // dummy entry widget (does not respond to input)
+  cmCursesCacheEntryComposite comp("EMPTY CACHE", 30, 30);
+  comp.Entry = cm::make_unique<cmCursesDummyWidget>(1, 1, 1, 1);
+  newEntries.emplace_back(std::move(comp));
+
+  if (count > 0) {
     // Create the composites.
 
     // First add entries which are new
@@ -190,7 +190,8 @@ void cmCursesMainForm::RePost()
     this->Fields.push_back(entry.Entry->Field);
   }
   // if no cache entries there should still be one dummy field
-  if (this->Fields.empty()) {
+  this->IsEmpty = this->Fields.empty();
+  if (this->IsEmpty) {
     const auto& front = this->Entries.front();
     this->Fields.push_back(front.Label->Field);
     this->Fields.push_back(front.IsNewLabel->Field);
@@ -869,7 +870,7 @@ void cmCursesMainForm::HandleInput()
         }
       }
       // delete cache entry
-      else if (key == 'd' && this->NumberOfVisibleEntries) {
+      else if (key == 'd' && this->NumberOfVisibleEntries && !this->IsEmpty) {
         this->OkToGenerate = false;
         FIELD* cur = current_field(this->Form);
         size_t findex = field_index(cur);
diff --git a/Source/CursesDialog/cmCursesMainForm.h b/Source/CursesDialog/cmCursesMainForm.h
index 9eb6418..fb44a45 100644
--- a/Source/CursesDialog/cmCursesMainForm.h
+++ b/Source/CursesDialog/cmCursesMainForm.h
@@ -161,6 +161,7 @@ protected:
   bool OkToGenerate = false;
   // Number of pages displayed
   int NumberOfPages = 0;
+  bool IsEmpty = false;
 
   int InitialWidth;
   std::unique_ptr<cmake> CMakeInstance;
-- 
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