Ensure no key end up missing in ResolveInternal and fix #1209

src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs

@@ -29,6 +29,33 @@ public void Issue1208()
             }
         }
 
+        [Fact]
+        public void Issue1209()
+        {
+            var path = IntegrationHelpers.GetDocumentPath("MOZILLA-9176-2.pdf");
+
+            using (var document = PdfDocument.Open(path, new ParsingOptions() { UseLenientParsing = true }))
+            {
+                for (int p = 1; p <= document.NumberOfPages; p++)
+                {
+                    var page = document.GetPage(p);
+                    Assert.NotNull(page);
+
+                    foreach (var image in page.GetImages())
+                    {
+                        Assert.True(image.ImageDictionary.ContainsKey(NameToken.Height)); // Was missing
+                        Assert.True(image.ImageDictionary.ContainsKey(NameToken.Width));
+
+                        if (image.ImageDictionary.TryGet<DictionaryToken>(NameToken.DecodeParms, out var decodeParms))
+                        {
+                            Assert.True(decodeParms.ContainsKey(NameToken.Columns)); // Was missing
+                            Assert.True(decodeParms.ContainsKey(NameToken.Rows));
+                        }
+                    }
+                }
+            }
+        }
+
         [Fact]
         public void Revert_e11dc6b()
         {

src/UglyToad.PdfPig/PdfExtensions.cs

@@ -2,6 +2,7 @@
 {
     using System;
     using System.Diagnostics.CodeAnalysis;
+    using System.Linq;
     using Core;
     using Filters;
     using Parser.Parts;
@@ -156,6 +157,23 @@ private static double GetEstimatedSizeMultiplier(IFilter filter)
                     resolvedItems[NameToken.Create(kvp.Key)] = ResolveInternal(value, scanner, visited);
                 }
 
+                if (resolvedItems.Count != dict.Data.Count)
+                {
+                    if (resolvedItems.Count > dict.Data.Count)
+                    {
+                        throw new InvalidOperationException("Resolved more items than were present in the original dictionary. This should not be possible.");
+                    }
+
+                    // We missed some due to cycles, try and resolve them now.
+                    foreach (var missing in dict.Data.Keys.Except(resolvedItems.Keys.Select(k => k.Data), StringComparer.OrdinalIgnoreCase))
+                    {
+                        if (dict.Data[missing] is IndirectReferenceToken reference)
+                        {
+                            resolvedItems[NameToken.Create(missing)] = ResolveInternal(reference, scanner, visited);
+                        }
+                    }
+                }
+
                 return new DictionaryToken(resolvedItems);
             }