Merge pull request #2169 from GitoxideLabs/copilot/fix-54bce74a-dc5e-4361-b53b-326c16b34046

Remove special handling of empty blob hash in gix - treat as error if not found

Author: Byron

gix/src/repository/object.rs

@@ -50,14 +50,6 @@ impl crate::Repository {
                 repo: self,
             });
         }
-        if id == ObjectId::empty_blob(self.object_hash()) {
-            return Ok(Object {
-                id,
-                kind: gix_object::Kind::Blob,
-                data: Vec::new(),
-                repo: self,
-            });
-        }
         let mut buf = self.free_buf();
         let kind = self.objects.find(&id, &mut buf)?.kind;
         Ok(Object::from_data(id, kind, buf, self))
@@ -106,12 +98,6 @@ impl crate::Repository {
                 size: 0,
             });
         }
-        if id == ObjectId::empty_blob(self.object_hash()) {
-            return Ok(gix_odb::find::Header::Loose {
-                kind: gix_object::Kind::Blob,
-                size: 0,
-            });
-        }
         self.objects.header(id)
     }
 
@@ -126,7 +112,7 @@ impl crate::Repository {
     #[doc(alias = "exists", alias = "git2")]
     pub fn has_object(&self, id: impl AsRef<gix_hash::oid>) -> bool {
         let id = id.as_ref();
-        if id.to_owned().is_empty_tree() || id.to_owned().is_empty_blob() {
+        if id.to_owned().is_empty_tree() {
             true
         } else {
             self.objects.exists(id)
@@ -147,12 +133,6 @@ impl crate::Repository {
                 size: 0,
             }));
         }
-        if id == ObjectId::empty_blob(self.object_hash()) {
-            return Ok(Some(gix_odb::find::Header::Loose {
-                kind: gix_object::Kind::Blob,
-                size: 0,
-            }));
-        }
         self.objects.try_header(&id).map_err(Into::into)
     }
 
@@ -167,14 +147,6 @@ impl crate::Repository {
                 repo: self,
             }));
         }
-        if id == ObjectId::empty_blob(self.object_hash()) {
-            return Ok(Some(Object {
-                id,
-                kind: gix_object::Kind::Blob,
-                data: Vec::new(),
-                repo: self,
-            }));
-        }
 
         let mut buf = self.free_buf();
         match self.objects.try_find(&id, &mut buf)? {
@@ -466,7 +438,7 @@ impl crate::Repository {
     /// This means that this object can be used in an uninitialized, empty repository which would report to have no objects at all.
     pub fn empty_blob(&self) -> Blob<'_> {
         Blob {
-            id: gix_hash::ObjectId::empty_blob(self.object_hash()),
+            id: self.object_hash().empty_blob(),
             data: Vec::new(),
             repo: self,
         }

gix/tests/gix/repository/object.rs

@@ -432,6 +432,7 @@ mod find {
     use gix_pack::Find;
 
     use crate::basic_repo;
+    use crate::repository::object::empty_bare_in_memory_repo;
 
     #[test]
     fn find_and_try_find_with_and_without_object_cache() -> crate::Result {
@@ -512,18 +513,23 @@ mod find {
     }
 
     #[test]
-    fn empty_blob_can_always_be_found() -> crate::Result {
+    fn empty_blob_can_be_found_if_it_exists() -> crate::Result {
         let repo = basic_repo()?;
         let empty_blob = gix::hash::ObjectId::empty_blob(repo.object_hash());
-        assert_eq!(repo.find_object(empty_blob)?.into_blob().data.len(), 0);
+
+        assert_eq!(
+            repo.find_object(empty_blob)?.into_blob().data.len(),
+            0,
+            "The basic_repo fixture contains an empty blob"
+        );
         assert!(repo.has_object(empty_blob));
         assert_eq!(
             repo.find_header(empty_blob)?,
             gix_odb::find::Header::Loose {
                 kind: gix_object::Kind::Blob,
                 size: 0,
             },
-            "empty blob is considered a loose object"
+            "empty blob is found when it exists in the repository"
         );
         assert_eq!(
             repo.try_find_object(empty_blob)?
@@ -539,46 +545,51 @@ mod find {
                 kind: gix_object::Kind::Blob,
                 size: 0,
             }),
-            "empty blob is considered a loose object"
+            "empty blob is found when it exists in the repository"
         );
         Ok(())
     }
+
+    #[test]
+    fn empty_blob() -> crate::Result {
+        let repo = empty_bare_in_memory_repo()?;
+        let empty_blob = repo.empty_blob();
+
+        assert_eq!(empty_blob.id, repo.object_hash().empty_blob());
+        assert_eq!(empty_blob.data.len(), 0);
+
+        assert!(!repo.has_object(empty_blob.id), "it doesn't exist by default");
+        repo.write_blob(&empty_blob.data)?;
+        assert!(repo.has_object(empty_blob.id), "it exists after it was written");
+
+        Ok(())
+    }
 }
 
 #[test]
 fn empty_objects_are_always_present_but_not_in_plumbing() -> crate::Result {
     let repo = empty_bare_in_memory_repo()?;
-    let empty_blob_id = gix::hash::ObjectId::empty_blob(repo.object_hash());
+    let empty_blob_id = repo.object_hash().empty_blob();
 
     assert!(
-        repo.has_object(empty_blob_id),
-        "empty object is always present even if it's not"
+        !repo.has_object(empty_blob_id),
+        "empty blob is not present unless it actually exists"
     );
     assert!(!repo.objects.contains(&empty_blob_id));
 
-    let header = repo.find_header(empty_blob_id)?;
-    assert_eq!(header.kind(), gix_object::Kind::Blob);
-    assert_eq!(header.size(), 0);
+    assert!(
+        repo.find_header(empty_blob_id).is_err(),
+        "Empty blob doesn't exist automatically just like in Git"
+    );
     assert_eq!(repo.objects.try_header(&empty_blob_id)?, None);
 
-    let header = repo.try_find_header(empty_blob_id)?.expect("should find header");
-    assert_eq!(header.kind(), gix_object::Kind::Blob);
-    assert_eq!(header.size(), 0);
-
-    let obj = repo.find_object(empty_blob_id)?;
-    assert_eq!(obj.kind, gix_object::Kind::Blob);
-    assert_eq!(obj.data.len(), 0);
+    assert_eq!(repo.try_find_header(empty_blob_id)?, None);
+    assert!(repo.find_object(empty_blob_id).is_err());
 
+    assert!(repo.try_find_object(empty_blob_id)?.is_none());
     let mut buf = Vec::new();
     assert_eq!(repo.objects.try_find(&empty_blob_id, &mut buf)?, None);
 
-    let obj = repo.try_find_object(empty_blob_id)?.expect("should find object");
-    assert_eq!(obj.kind, gix_object::Kind::Blob);
-    assert_eq!(obj.data.len(), 0);
-
-    let blob = obj.try_into_blob()?;
-    assert_eq!(blob.data.len(), 0);
-
     Ok(())
 }