From fc6b8385bd534fec4ec3f4f42830b447f16ffdc6 Mon Sep 17 00:00:00 2001
From: Ben Fry <ben@fathom.info>
Date: Fri, 18 Jan 2019 11:19:28 -0800
Subject: [PATCH] prevent infinite "sketch disappeared" warnings (fixes #4805)

---
 app/src/processing/app/Sketch.java | 43 ++++++++++++++++++------------
 todo.txt                           | 12 ++++-----
 2 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/app/src/processing/app/Sketch.java b/app/src/processing/app/Sketch.java
index 40a3d7fb2..15882dfb5 100644
--- a/app/src/processing/app/Sketch.java
+++ b/app/src/processing/app/Sketch.java
@@ -40,7 +40,9 @@ import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.io.*;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import javax.swing.*;
@@ -1497,29 +1499,36 @@ public class Sketch {
   */
 
 
+  private Set<File> existenceWarnings = new HashSet<>();
+
   /**
-   * Make sure the sketch hasn't been moved or deleted by some
-   * nefarious user. If they did, try to re-create it and save.
-   * Only checks to see if the main folder is still around,
-   * but not its contents.
+   * Make sure the sketch hasn't been moved or deleted by a nefarious user.
+   * If they did, try to re-create it and save. Only checks whether the
+   * main folder is still around, but not its contents.
    */
   public void ensureExistence() {
     if (!folder.exists()) {
-      // Disaster recovery, try to salvage what's there already.
-      Messages.showWarning(Language.text("ensure_exist.messages.missing_sketch"),
-                           Language.text("ensure_exist.messages.missing_sketch.description"));
-      try {
-        folder.mkdirs();
-        modified = true;
+      // Avoid an infinite loop if we've already warned about this
+      // https://github.com/processing/processing/issues/4805
+      if (!existenceWarnings.contains(folder)) {
+        existenceWarnings.add(folder);
 
-        for (int i = 0; i < codeCount; i++) {
-          code[i].save();  // this will force a save
+        // Disaster recovery, try to salvage what's there already.
+        Messages.showWarning(Language.text("ensure_exist.messages.missing_sketch"),
+                             Language.text("ensure_exist.messages.missing_sketch.description"));
+        try {
+          folder.mkdirs();
+          modified = true;
+
+          for (int i = 0; i < codeCount; i++) {
+            code[i].save();  // this will force a save
+          }
+          calcModified();
+
+        } catch (Exception e) {
+          Messages.showWarning(Language.text("ensure_exist.messages.unrecoverable"),
+                               Language.text("ensure_exist.messages.unrecoverable.description"), e);
         }
-        calcModified();
-
-      } catch (Exception e) {
-        Messages.showWarning(Language.text("ensure_exist.messages.unrecoverable"),
-                             Language.text("ensure_exist.messages.unrecoverable.description"), e);
       }
     }
   }
diff --git a/todo.txt b/todo.txt
index 6b47d382e..a1f4d2dc0 100755
--- a/todo.txt
+++ b/todo.txt
@@ -22,6 +22,12 @@ jakub
 X Fix sketch exception getting hidden by warning
 X   https://github.com/processing/processing/pull/5486
 X   https://github.com/processing/processing/issues/5412
+X EventQueue problems with "could not find sketch size" message
+X   https://github.com/processing/processing/issues/4893
+X   https://github.com/processing/processing/pull/5708
+X   https://github.com/processing/processing/issues/5030 (duplicate)
+X size(0, 0) just freezes instead of showing an error
+X   https://github.com/processing/processing/issues/5233 (duplicate)
 
 
 _ Find in Reference disabled for various keywords (draw, for, if, catch, while)
@@ -38,12 +44,6 @@ _   seen in Eclipse; have to turn on the debugger
 _ "Sketch disappeared" infinite pop up dialogs
 _   https://github.com/processing/processing/pull/4808
 _   https://github.com/processing/processing/issues/4805
-_ EventQueue problems with "could not find sketch size" message
-_   https://github.com/processing/processing/issues/4893
-X   https://github.com/processing/processing/pull/5708
-X   https://github.com/processing/processing/issues/5030 (duplicate)
-_ size(0, 0) just freezes instead of showing an error
-X   https://github.com/processing/processing/issues/5233 (duplicate)
 
 
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