Update

Author: jairbubbles

LibGit2Sharp/Blob.cs

@@ -8,14 +8,17 @@ namespace LibGit2Sharp
     /// <summary>
     /// Stores the binary content of a tracked file.
     /// </summary>
+    /// <remarks>
+    /// Since the introduction of partially cloned repositories, blobs might be missing on your local repository (see https://git-scm.com/docs/partial-clone)
+    /// </remarks>
     public class Blob : GitObject
     {
         private readonly ILazy<Int64> lazySize;
         private readonly ILazy<bool> lazyIsBinary;
-        private readonly ILazy<bool> lazyIsDownloaded;
+        private readonly ILazy<bool> lazyIsMissing;
 
         /// <summary>
-        /// Needed for mocking purposes.
+        /// Needed for mocking purposes.s
         /// </summary>
         protected Blob()
         { }
@@ -25,7 +28,7 @@ internal Blob(Repository repo, ObjectId id)
         {
             lazySize = GitObjectLazyGroup.Singleton(repo, id, Proxy.git_blob_rawsize);
             lazyIsBinary = GitObjectLazyGroup.Singleton(repo, id, Proxy.git_blob_is_binary);
-            lazyIsDownloaded = GitObjectLazyGroup.Singleton(repo, id, handle => handle != null);
+            lazyIsMissing = GitObjectLazyGroup.Singleton(repo, id, handle => handle == null);
         }
 
         /// <summary>
@@ -35,22 +38,25 @@ internal Blob(Repository repo, ObjectId id)
         /// can be used.
         /// </para>
         /// </summary>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual long Size => lazySize.Value;
 
         /// <summary>
         ///  Determine if the blob content is most certainly binary or not.
         /// </summary>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual bool IsBinary => lazyIsBinary.Value;
 
 
         /// <summary>
-        ///  Determine if the blob content was downloaded (happens with partially cloned repositories)
+        ///  Determine if the blob content is missing ( with partially cloned repositories)
         /// </summary>
-        public virtual bool IsDownloaded => lazyIsDownloaded.Value;
+        public virtual bool IsMissing => lazyIsMissing.Value;
 
         /// <summary>
         /// Gets the blob content in a <see cref="Stream"/>.
         /// </summary>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual Stream GetContentStream()
         {
             return Proxy.git_blob_rawcontent_stream(repo.Handle, Id, Size);
@@ -61,6 +67,7 @@ public virtual Stream GetContentStream()
         /// checked out to the working directory.
         /// <param name="filteringOptions">Parameter controlling content filtering behavior</param>
         /// </summary>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual Stream GetContentStream(FilteringOptions filteringOptions)
         {
             Ensure.ArgumentNotNull(filteringOptions, "filteringOptions");
@@ -72,6 +79,7 @@ public virtual Stream GetContentStream(FilteringOptions filteringOptions)
         /// Gets the blob content, decoded with UTF8 encoding if the encoding cannot be detected from the byte order mark
         /// </summary>
         /// <returns>Blob content as text.</returns>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual string GetContentText()
         {
             return ReadToEnd(GetContentStream(), null);
@@ -83,6 +91,7 @@ public virtual string GetContentText()
         /// </summary>
         /// <param name="encoding">The encoding of the text to use, if it cannot be detected</param>
         /// <returns>Blob content as text.</returns>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual string GetContentText(Encoding encoding)
         {
             Ensure.ArgumentNotNull(encoding, "encoding");
@@ -95,6 +104,7 @@ public virtual string GetContentText(Encoding encoding)
         /// </summary>
         /// <param name="filteringOptions">Parameter controlling content filtering behavior</param>
         /// <returns>Blob content as text.</returns>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual string GetContentText(FilteringOptions filteringOptions)
         {
             return GetContentText(filteringOptions, null);
@@ -109,6 +119,7 @@ public virtual string GetContentText(FilteringOptions filteringOptions)
         /// <param name="filteringOptions">Parameter controlling content filtering behavior</param>
         /// <param name="encoding">The encoding of the text. (default: detected or UTF8)</param>
         /// <returns>Blob content as text.</returns>
+        /// <exception cref="NotFoundException">Throws if blob is missing</exception>
         public virtual string GetContentText(FilteringOptions filteringOptions, Encoding encoding)
         {
             Ensure.ArgumentNotNull(filteringOptions, "filteringOptions");

LibGit2Sharp/Core/GitObjectLazyGroup.cs

@@ -17,6 +17,9 @@ protected override void EvaluateInternal(Action<ObjectHandle> evaluator)
         {
             using (var osw = new ObjectSafeWrapper(id, repo.Handle))
             {
+                if (osw.ObjectPtr == null)
+                    throw new NotFoundException($"Object {id} is not available");
+
                 evaluator(osw.ObjectPtr);
             }
         }
@@ -28,7 +31,7 @@ public static ILazy<TResult> Singleton<TResult>(Repository repo, ObjectId id, Fu
                 using (var osw = new ObjectSafeWrapper(id, repo.Handle))
                 {
                     if (osw.ObjectPtr == null)
-                        throw new NotFoundException($"Blob {id} is not available");
+                        throw new NotFoundException($"Object {id} is not available");
 
                     return resultSelector(osw.ObjectPtr);
                 }