thodg/libgit2

diff --git a/README.md b/README.md
index 1254adc..dae6a76 100644
--- a/README.md
+++ b/README.md
@@ -85,8 +85,8 @@ The waf build system for libgit2 accepts the following flags:
 	--arch=[ia64|x64|x86|x86_amd64|x86_ia64]
 		Force a specific architecture for compilers that support it.
 
-	--without-sqlite
-		Disable sqlite support.
+	--with-sqlite
+		Enable sqlite support.
 
 You can run `./waf --help` to see a full list of install options and
 targets.
diff --git a/include/git2/tag.h b/include/git2/tag.h
index ee92cd5..c751a13 100644
--- a/include/git2/tag.h
+++ b/include/git2/tag.h
@@ -140,7 +140,8 @@ GIT_EXTERN(const char *) git_tag_message(git_tag *t);
  * @param repo Repository where to store the tag
  *
  * @param tag_name Name for the tag; this name is validated
- * for consistency
+ * for consistency. It should also not conflict with an 
+ * already existing tag name
  *
  * @param target OID to which this tag points; note that no
  *	validation is done on this OID. Use the _o version of this
@@ -188,6 +189,92 @@ GIT_EXTERN(int) git_tag_create_o(
 		const git_signature *tagger,
 		const char *message);
 
+/**
+ * Create a new tag in the repository from a buffer
+ *
+ * @param oid Pointer where to store the OID of the newly created tag
+ *
+ * @param repo Repository where to store the tag
+ *
+ * @param buffer Raw tag data
+ */
+GIT_EXTERN(int) git_tag_create_frombuffer(
+		git_oid *oid,
+		git_repository *repo,
+		const char *buffer);
+
+/**
+ * Create a new tag in the repository from an OID
+ * and overwrite an already existing tag reference, if any.
+ *
+ * @param oid Pointer where to store the OID of the
+ *	newly created tag
+ *
+ * @param repo Repository where to store the tag
+ *
+ * @param tag_name Name for the tag; this name is validated
+ * for consistency.
+ *
+ * @param target OID to which this tag points; note that no
+ *	validation is done on this OID. Use the _fo version of this
+ *	method to assure a proper object is being tagged
+ *
+ * @param target_type Type of the tagged OID; note that no
+ *	validation is performed here either
+ *
+ * @param tagger Signature of the tagger for this tag, and
+ *  of the tagging time
+ *
+ * @param message Full message for this tag
+ *
+ * @return 0 on success; error code otherwise.
+ *	A tag object is written to the ODB, and a proper reference
+ *	is written in the /refs/tags folder, pointing to it
+ */
+GIT_EXTERN(int) git_tag_create_f(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_oid *target,
+		git_otype target_type,
+		const git_signature *tagger,
+		const char *message);
+
+/**
+ * Create a new tag in the repository from an existing
+ * `git_object` instance and overwrite an already existing 
+ * tag reference, if any.
+ *
+ * This method replaces the `target` and `target_type`
+ * paremeters of `git_tag_create_f` by a single instance
+ * of a `const git_object *`, which is assured to be
+ * a proper object in the ODB and hence will create
+ * a valid tag
+ *
+ * @see git_tag_create_f
+ */
+GIT_EXTERN(int) git_tag_create_fo(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_object *target,
+		const git_signature *tagger,
+		const char *message);
+
+/**
+ * Delete an existing tag reference.
+ *
+ * @param repo Repository where lives the tag
+ *
+ * @param tag_name Name of the tag to be deleted;
+ * this name is validated for consistency.
+ *
+ * @return 0 on success; error code otherwise.
+ */
+GIT_EXTERN(int) git_tag_delete(
+		git_repository *repo,
+		const char *tag_name);
+
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/include/git2/tree.h b/include/git2/tree.h
index 164aec9..0caf60a 100644
--- a/include/git2/tree.h
+++ b/include/git2/tree.h
@@ -93,7 +93,7 @@ GIT_EXTERN(size_t) git_tree_entrycount(git_tree *tree);
  * @param filename the filename of the desired entry
  * @return the tree entry; NULL if not found
  */
-GIT_EXTERN(git_tree_entry *) git_tree_entry_byname(git_tree *tree, const char *filename);
+GIT_EXTERN(const git_tree_entry *) git_tree_entry_byname(git_tree *tree, const char *filename);
 
 /**
  * Lookup a tree entry by its position in the tree
@@ -102,7 +102,7 @@ GIT_EXTERN(git_tree_entry *) git_tree_entry_byname(git_tree *tree, const char *f
  * @param idx the position in the entry list
  * @return the tree entry; NULL if not found
  */
-GIT_EXTERN(git_tree_entry *) git_tree_entry_byindex(git_tree *tree, int idx);
+GIT_EXTERN(const git_tree_entry *) git_tree_entry_byindex(git_tree *tree, int idx);
 
 /**
  * Get the UNIX file attributes of a tree entry
@@ -110,7 +110,7 @@ GIT_EXTERN(git_tree_entry *) git_tree_entry_byindex(git_tree *tree, int idx);
  * @param entry a tree entry
  * @return attributes as an integer
  */
-GIT_EXTERN(unsigned int) git_tree_entry_attributes(git_tree_entry *entry);
+GIT_EXTERN(unsigned int) git_tree_entry_attributes(const git_tree_entry *entry);
 
 /**
  * Get the filename of a tree entry
@@ -118,7 +118,7 @@ GIT_EXTERN(unsigned int) git_tree_entry_attributes(git_tree_entry *entry);
  * @param entry a tree entry
  * @return the name of the file
  */
-GIT_EXTERN(const char *) git_tree_entry_name(git_tree_entry *entry);
+GIT_EXTERN(const char *) git_tree_entry_name(const git_tree_entry *entry);
 
 /**
  * Get the id of the object pointed by the entry
@@ -126,7 +126,7 @@ GIT_EXTERN(const char *) git_tree_entry_name(git_tree_entry *entry);
  * @param entry a tree entry
  * @return the oid of the object
  */
-GIT_EXTERN(const git_oid *) git_tree_entry_id(git_tree_entry *entry);
+GIT_EXTERN(const git_oid *) git_tree_entry_id(const git_tree_entry *entry);
 
 /**
  * Convert a tree entry to the git_object it points too.
@@ -134,9 +134,132 @@ GIT_EXTERN(const git_oid *) git_tree_entry_id(git_tree_entry *entry);
  * @param object pointer to the converted object
  * @param repo repository where to lookup the pointed object
  * @param entry a tree entry
- * @return a reference to the pointed object in the repository
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_tree_entry_2object(git_object **object_out, git_repository *repo, const git_tree_entry *entry);
+
+/**
+ * Write a tree to the ODB from the index file
+ *
+ * This method will scan the index and write a representation
+ * of its current state back to disk; it recursively creates
+ * tree objects for each of the subtrees stored in the index,
+ * but only returns the OID of the root tree. This is the OID
+ * that can be used e.g. to create a commit.
+ *
+ * The index instance cannot be bare, and needs to be associated
+ * to an existing repository.
+ *
+ * @param oid Pointer where to store the written tree
+ * @param index Index to write
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_tree_create_fromindex(git_oid *oid, git_index *index);
+
+/**
+ * Create a new tree builder.
+ *
+ * The tree builder can be used to create or modify
+ * trees in memory and write them as tree objects to the
+ * database.
+ *
+ * If the `source` parameter is not NULL, the tree builder
+ * will be initialized with the entries of the given tree.
+ * 
+ * If the `source` parameter is NULL, the tree builder will
+ * have no entries and will have to be filled manually.
+ *
+ * @param builder_p Pointer where to store the tree builder
+ * @param source Source tree to initialize the builder (optional)
+ * @return 0 on sucess; error code otherwise
+ */
+GIT_EXTERN(int) git_treebuilder_create(git_treebuilder **builder_p, const git_tree *source);
+
+/**
+ * Clear all the entires in the builder
+ *
+ * @param bld Builder to clear
+ */
+GIT_EXTERN(void) git_treebuilder_clear(git_treebuilder *bld);
+
+/**
+ * Free a tree builder
+ *
+ * This will clear all the entries and free to builder.
+ * Failing to free the builder after you're done using it
+ * will result in a memory leak
+ *
+ * @param bld Builder to free
+ */
+GIT_EXTERN(void) git_treebuilder_free(git_treebuilder *bld);
+
+/**
+ * Get an entry from the builder from its filename
+ *
+ * The returned entry is owned by the builder and should
+ * not be freed manually.
+ *
+ * @param bld Tree builder
+ * @param filename Name of the entry
+ * @return pointer to the entry; NULL if not found
+ */
+GIT_EXTERN(const git_tree_entry *) git_treebuilder_get(git_treebuilder *bld, const char *filename);
+
+/**
+ * Add or update an entry to the builder
+ *
+ * Insert a new entry for `filename` in the builder with the
+ * given attributes.
+ *
+ * if an entry named `filename` already exists, its attributes
+ * will be updated with the given ones.
+ *
+ * The optional pointer `entry_out` can be used to retrieve a
+ * pointer to the newly created/updated entry.
+ *
+ * @param entry_out Pointer to store the entry (optional)
+ * @param bld Tree builder
+ * @param filename Filename of the entry
+ * @param id SHA1 oid of the entry
+ * @param attributes Folder attributes of the entry
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_treebuilder_insert(git_tree_entry **entry_out, git_treebuilder *bld, const char *filename, const git_oid *id, unsigned int attributes);
+
+/**
+ * Remove an entry from the builder by its filename
+ *
+ * @param bld Tree builder
+ * @param filename Filename of the entry to remove
+ */
+GIT_EXTERN(int) git_treebuilder_remove(git_treebuilder *bld, const char *filename);
+
+/**
+ * Filter the entries in the tree
+ *
+ * The `filter` callback will be called for each entry
+ * in the tree with a pointer to the entry and the
+ * provided `payload`: if the callback returns 1, the
+ * entry will be filtered (removed from the builder).
+ *
+ * @param bld Tree builder
+ * @param filter Callback to filter entries
+ */
+GIT_EXTERN(void) git_treebuilder_filter(git_treebuilder *bld, int (*filter)(const git_tree_entry *, void *), void *payload);
+
+/**
+ * Write the contents of the tree builder as a tree object
+ *
+ * The tree builder will be written to the given `repo`, and
+ * it's identifying SHA1 hash will be stored in the `oid`
+ * pointer.
+ *
+ * @param oid Pointer where to store the written OID
+ * @param repo Repository where to store the object
+ * @param bld Tree builder to write
+ * @return 0 on success; error code otherwise
  */
-GIT_EXTERN(int) git_tree_entry_2object(git_object **object_out, git_repository *repo, git_tree_entry *entry);
+GIT_EXTERN(int) git_treebuilder_write(git_oid *oid, git_repository *repo, git_treebuilder *bld);
 
 /** @} */
 GIT_END_DECL
diff --git a/include/git2/types.h b/include/git2/types.h
index cb5adcc..84e3d5b 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -124,6 +124,9 @@ typedef struct git_tree_entry git_tree_entry;
 /** Representation of a tree object. */
 typedef struct git_tree git_tree;
 
+/** Constructor for in-memory trees */
+typedef struct git_treebuilder git_treebuilder;
+
 /** Memory representation of an index file. */
 typedef struct git_index git_index;
 
diff --git a/src/commit.c b/src/commit.c
index 03b111d..9fc3f07 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -235,9 +235,9 @@ int git_commit_create(
 	return error;
 }
 
-int commit_parse_buffer(git_commit *commit, void *data, size_t len)
+int commit_parse_buffer(git_commit *commit, const void *data, size_t len)
 {
-	char *buffer = (char *)data;
+	const char *buffer = (char *)data;
 	const char *buffer_end = (char *)data + len;
 
 	git_oid parent_oid;
diff --git a/src/odb.c b/src/odb.c
index 33d5468..43d0ef9 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -149,6 +149,69 @@ int git_odb_hash(git_oid *id, const void *data, size_t len, git_otype type)
 	return git_odb__hash_obj(id, hdr, sizeof(hdr), &hdrlen, &raw);
 }
 
+/**
+ * FAKE WSTREAM
+ */
+
+typedef struct {
+	git_odb_stream stream;
+	char *buffer;
+	size_t size, written;
+	git_otype type;
+} fake_wstream;
+
+static int fake_wstream__fwrite(git_oid *oid, git_odb_stream *_stream)
+{
+	fake_wstream *stream = (fake_wstream *)_stream;
+	return _stream->backend->write(oid, _stream->backend, stream->buffer, stream->size, stream->type);
+}
+
+static int fake_wstream__write(git_odb_stream *_stream, const char *data, size_t len)
+{
+	fake_wstream *stream = (fake_wstream *)_stream;
+
+	if (stream->written + len >= stream->size)
+		return GIT_ENOMEM;
+
+	memcpy(stream->buffer + stream->written, data, len);
+	stream->written += len;
+	return GIT_SUCCESS;
+}
+
+static void fake_wstream__free(git_odb_stream *_stream)
+{
+	fake_wstream *stream = (fake_wstream *)_stream;
+
+	free(stream->buffer);
+	free(stream);
+}
+
+static int init_fake_wstream(git_odb_stream **stream_p, git_odb_backend *backend, size_t size, git_otype type)
+{
+	fake_wstream *stream;
+
+	stream = git__calloc(1, sizeof(fake_wstream));
+	if (stream == NULL)
+		return GIT_ENOMEM;
+
+	stream->size = size;
+	stream->type = type;
+	stream->buffer = git__malloc(size);
+	if (stream->buffer == NULL) {
+		free(stream);
+		return GIT_ENOMEM;
+	}
+
+	stream->stream.backend = backend;
+	stream->stream.read = NULL; /* read only */
+	stream->stream.write = &fake_wstream__write;
+	stream->stream.finalize_write = &fake_wstream__fwrite;
+	stream->stream.free = &fake_wstream__free;
+	stream->stream.mode = GIT_STREAM_WRONLY;
+
+	*stream_p = (git_odb_stream *)stream;
+	return GIT_SUCCESS;
+}
 
 /***********************************************************
  *
@@ -467,6 +530,8 @@ int git_odb_open_wstream(git_odb_stream **stream, git_odb *db, size_t size, git_
 
 		if (b->writestream != NULL)
 			error = b->writestream(stream, b, size, type);
+		else if (b->write != NULL)
+			error = init_fake_wstream(stream, b, size, type);
 	}
 
 	return error;
diff --git a/src/oid.c b/src/oid.c
index eb167a6..86c1e00 100644
--- a/src/oid.c
+++ b/src/oid.c
@@ -118,13 +118,13 @@ char *git_oid_to_string(char *out, size_t n, const git_oid *oid)
 	return out;
 }
 
-int git__parse_oid(git_oid *oid, char **buffer_out,
+int git__parse_oid(git_oid *oid, const char **buffer_out,
 		const char *buffer_end, const char *header)
 {
 	const size_t sha_len = GIT_OID_HEXSZ;
 	const size_t header_len = strlen(header);
 
-	char *buffer = *buffer_out;
+	const char *buffer = *buffer_out;
 
 	if (buffer + (header_len + sha_len + 1) > buffer_end)
 		return GIT_EOBJCORRUPTED;
diff --git a/src/repository.c b/src/repository.c
index 91b95a8..abbbd12 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -346,7 +346,7 @@ static int repo_init_reinit(repo_init *results)
 {
 	/* TODO: reinit the repository */
 	results->has_been_reinit = 1;
-	return GIT_SUCCESS;
+	return GIT_ENOTIMPLEMENTED;
 }
 
 static int repo_init_createhead(git_repository *repo)
diff --git a/src/repository.h b/src/repository.h
index fef1c7d..813cac9 100644
--- a/src/repository.h
+++ b/src/repository.h
@@ -43,7 +43,7 @@ struct git_repository {
  * export */
 void git_object__free(void *object);
 
-int git__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_end, const char *header);
+int git__parse_oid(git_oid *oid, const char **buffer_out, const char *buffer_end, const char *header);
 int git__write_oid(git_odb_stream *src, const char *header, const git_oid *oid);
 
 #endif
diff --git a/src/signature.c b/src/signature.c
index 4126376..0c99755 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -109,14 +109,14 @@ static int parse_timezone_offset(const char *buffer, int *offset_out)
 }
 
 
-int git_signature__parse(git_signature *sig, char **buffer_out,
+int git_signature__parse(git_signature *sig, const char **buffer_out,
 		const char *buffer_end, const char *header)
 {
 	const size_t header_len = strlen(header);
 
 	int name_length, email_length;
-	char *buffer = *buffer_out;
-	char *line_end, *name_end, *email_end;
+	const char *buffer = *buffer_out;
+	const char *line_end, *name_end, *email_end;
 	int offset = 0;
 
 	memset(sig, 0x0, sizeof(git_signature));
@@ -159,7 +159,7 @@ int git_signature__parse(git_signature *sig, char **buffer_out,
 	if (buffer >= line_end)
 		return GIT_EOBJCORRUPTED;
 
-	sig->when.time = strtol(buffer, &buffer, 10);
+	sig->when.time = strtol(buffer, (char **)&buffer, 10);
 
 	if (sig->when.time == 0)
 		return GIT_EOBJCORRUPTED;
diff --git a/src/signature.h b/src/signature.h
index 3534cb2..feba657 100644
--- a/src/signature.h
+++ b/src/signature.h
@@ -6,7 +6,7 @@
 #include "repository.h"
 #include <time.h>
 
-int git_signature__parse(git_signature *sig, char **buffer_out, const char *buffer_end, const char *header);
+int git_signature__parse(git_signature *sig, const char **buffer_out, const char *buffer_end, const char *header);
 int git_signature__write(char **signature, const char *header, const git_signature *sig);
 
 #endif
diff --git a/src/tag.c b/src/tag.c
index 7baabab..ef58e09 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -79,7 +79,7 @@ const char *git_tag_message(git_tag *t)
 	return t->message;
 }
 
-static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
+static int parse_tag_buffer(git_tag *tag, const char *buffer, const char *buffer_end)
 {
 	static const char *tag_types[] = {
 		NULL, "commit\n", "tree\n", "blob\n", "tag\n"
@@ -130,9 +130,6 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 
 	text_len = search - buffer;
 
-	if (tag->tag_name != NULL)
-		free(tag->tag_name);
-
 	tag->tag_name = git__malloc(text_len + 1);
 	memcpy(tag->tag_name, buffer, text_len);
 	tag->tag_name[text_len] = '\0';
@@ -141,8 +138,11 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 
 	tag->tagger = git__malloc(sizeof(git_signature));
 
-	if ((error = git_signature__parse(tag->tagger, &buffer, buffer_end, "tagger ")) != 0)
+	if ((error = git_signature__parse(tag->tagger, &buffer, buffer_end, "tagger ")) != 0) {
+		free(tag->tag_name);
+		git_signature_free(tag->tagger);
 		return error;
+	}
 
 	text_len = buffer_end - ++buffer;
 
@@ -153,39 +153,61 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 	return GIT_SUCCESS;
 }
 
-int git_tag_create_o(
-		git_oid *oid,
-		git_repository *repo,
-		const char *tag_name,
-		const git_object *target,
-		const git_signature *tagger,
-		const char *message)
+static int retreive_tag_reference(git_reference **tag_reference_out, char *ref_name_out, git_repository *repo, const char *tag_name)
 {
-	return git_tag_create(
-		oid, repo, tag_name, 
-		git_object_id(target),
-		git_object_type(target),
-		tagger, message);
+	git_reference *tag_ref;
+	int error;
+
+	git__joinpath(ref_name_out, GIT_REFS_TAGS_DIR, tag_name);
+	error = git_reference_lookup(&tag_ref, repo, ref_name_out);
+	if (error < GIT_SUCCESS)
+		return error;
+
+	*tag_reference_out = tag_ref;
+
+	return GIT_SUCCESS;
 }
 
-int git_tag_create(
+static int tag_create(
 		git_oid *oid,
 		git_repository *repo,
 		const char *tag_name,
 		const git_oid *target,
 		git_otype target_type,
 		const git_signature *tagger,
-		const char *message)
+		const char *message,
+		int allow_ref_overwrite)
 {
 	size_t final_size = 0;
 	git_odb_stream *stream;
 
 	const char *type_str;
 	char *tagger_str;
+	git_reference *new_ref;
+
+	char ref_name[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
 
 	int type_str_len, tag_name_len, tagger_str_len, message_len;
-	int error;
+	int error, should_update_ref = 0;
+
+	/** Ensure the tag name doesn't conflict with an already existing 
+	    reference unless overwriting has explictly been requested **/
+	error = retreive_tag_reference(&new_ref, ref_name, repo, tag_name);
 
+	switch (error) {
+	case GIT_SUCCESS:
+		if (!allow_ref_overwrite)
+			return GIT_EEXISTS;	
+		should_update_ref = 1;
+		
+		/* Fall trough */
+
+	case GIT_ENOTFOUND: 
+		break;
+
+	default:
+		return error;
+	}
 
 	type_str = git_object_type2string(target_type);
 
@@ -223,16 +245,120 @@ int git_tag_create(
 	error = stream->finalize_write(oid, stream);
 	stream->free(stream);
 
-	if (error == GIT_SUCCESS) {
-		char ref_name[512];
-		git_reference *new_ref;
-		git__joinpath(ref_name, GIT_REFS_TAGS_DIR, tag_name);
+	if (error < GIT_SUCCESS)
+		return error;
+
+	if (!should_update_ref)
 		error = git_reference_create_oid(&new_ref, repo, ref_name, oid);
-	}
+	else
+		error = git_reference_set_oid(new_ref, oid);
+	
+	return error;
+}
+
+int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *buffer)
+{
+	git_tag tag;
+	int error;
+	git_object *obj;
+
+	assert(oid && buffer);
+
+	memset(&tag, 0, sizeof(tag));
+
+	if ((error = parse_tag_buffer(&tag, buffer, buffer + strlen(buffer))) < GIT_SUCCESS)
+		return error;
+
+	error = git_object_lookup(&obj, repo, &tag.target, tag.type);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	error = git_tag_create_o(oid, repo, tag.tag_name, obj, tag.tagger, tag.message);
+
+	git_object_close(obj);
+
+cleanup:
+	git_signature_free(tag.tagger);
+	free(tag.tag_name);
+	free(tag.message);
 
 	return error;
 }
 
+int git_tag_create_o(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_object *target,
+		const git_signature *tagger,
+		const char *message)
+{
+	return tag_create(
+		oid, repo, tag_name, 
+		git_object_id(target),
+		git_object_type(target),
+		tagger, message, 0);
+}
+
+int git_tag_create(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_oid *target,
+		git_otype target_type,
+		const git_signature *tagger,
+		const char *message)
+{
+	return tag_create(
+		oid, repo, tag_name, 
+		target,
+		target_type,
+		tagger, message, 0);
+}
+
+int git_tag_create_fo(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_object *target,
+		const git_signature *tagger,
+		const char *message)
+{
+	return tag_create(
+		oid, repo, tag_name, 
+		git_object_id(target),
+		git_object_type(target),
+		tagger, message, 1);
+}
+
+int git_tag_create_f(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_oid *target,
+		git_otype target_type,
+		const git_signature *tagger,
+		const char *message)
+{
+	return tag_create(
+		oid, repo, tag_name, 
+		target,
+		target_type,
+		tagger, message, 1);
+}
+
+int git_tag_delete(git_repository *repo, const char *tag_name)
+{
+	int error;
+	git_reference *tag_ref;
+	char ref_name[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
+
+	error = retreive_tag_reference(&tag_ref, ref_name, repo, tag_name);
+	if (error < GIT_SUCCESS)
+		return error;
+
+	return git_reference_delete(tag_ref);
+}
 
 int git_tag__parse(git_tag *tag, git_odb_object *obj)
 {
diff --git a/src/tree.c b/src/tree.c
index 31b286e..693ed1c 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -33,6 +33,10 @@
 #define MAX_FILEMODE 0777777
 #define MAX_FILEMODE_BYTES 6
 
+static int valid_attributes(const int attributes) {
+	return attributes >= 0 && attributes <= MAX_FILEMODE; 
+}
+
 int entry_search_cmp(const void *key, const void *array_member)
 {
 	const char *filename = (const char *)key;
@@ -79,30 +83,30 @@ const git_oid *git_tree_id(git_tree *c)
 	return git_object_id((git_object *)c);
 }
 
-unsigned int git_tree_entry_attributes(git_tree_entry *entry)
+unsigned int git_tree_entry_attributes(const git_tree_entry *entry)
 {
 	return entry->attr;
 }
 
-const char *git_tree_entry_name(git_tree_entry *entry)
+const char *git_tree_entry_name(const git_tree_entry *entry)
 {
 	assert(entry);
 	return entry->filename;
 }
 
-const git_oid *git_tree_entry_id(git_tree_entry *entry)
+const git_oid *git_tree_entry_id(const git_tree_entry *entry)
 {
 	assert(entry);
 	return &entry->oid;
 }
 
-int git_tree_entry_2object(git_object **object_out, git_repository *repo, git_tree_entry *entry)
+int git_tree_entry_2object(git_object **object_out, git_repository *repo, const git_tree_entry *entry)
 {
 	assert(entry && object_out);
 	return git_object_lookup(object_out, repo, &entry->oid, GIT_OBJ_ANY);
 }
 
-git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
+const git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
 {
 	int idx;
 
@@ -115,7 +119,7 @@ git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
 	return git_vector_get(&tree->entries, idx);
 }
 
-git_tree_entry *git_tree_entry_byindex(git_tree *tree, int idx)
+const git_tree_entry *git_tree_entry_byindex(git_tree *tree, int idx)
 {
 	assert(tree);
 	return git_vector_get(&tree->entries, (unsigned int)idx);
@@ -127,7 +131,7 @@ size_t git_tree_entrycount(git_tree *tree)
 	return tree->entries.length;
 }
 
-static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
+static int tree_parse_buffer(git_tree *tree, const char *buffer, const char *buffer_end)
 {
 	int error = GIT_SUCCESS;
 
@@ -137,7 +141,7 @@ static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
 	while (buffer < buffer_end) {
 		git_tree_entry *entry;
 
-		entry = git__malloc(sizeof(git_tree_entry));
+		entry = git__calloc(1, sizeof(git_tree_entry));
 		if (entry == NULL) {
 			error = GIT_ENOMEM;
 			break;
@@ -146,7 +150,7 @@ static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
 		if (git_vector_insert(&tree->entries, entry) < GIT_SUCCESS)
 			return GIT_ENOMEM;
 
-		entry->attr = strtol(buffer, &buffer, 8);
+		entry->attr = strtol(buffer, (char **)&buffer, 8);
 
 		if (*buffer++ != ' ') {
 			error = GIT_EOBJCORRUPTED;
@@ -159,6 +163,7 @@ static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
 		}
 
 		entry->filename = git__strdup(buffer);
+		entry->filename_len = strlen(buffer);
 
 		while (buffer < buffer_end && *buffer != 0)
 			buffer++;
@@ -178,3 +183,304 @@ int git_tree__parse(git_tree *tree, git_odb_object *obj)
 	return tree_parse_buffer(tree, (char *)obj->raw.data, (char *)obj->raw.data + obj->raw.len);
 }
 
+static int write_index_entry(char *buffer, int mode, const char *path, size_t path_len, const git_oid *oid)
+{
+	int written;
+	written = sprintf(buffer, "%o %.*s%c", mode, (int)path_len, path, 0);
+	memcpy(buffer + written, &oid->id, GIT_OID_RAWSZ);
+	return written + GIT_OID_RAWSZ;
+}
+
+static int write_index(git_oid *oid, git_index *index, const char *base, int baselen, int entry_no, int maxentries)
+{
+	size_t size, offset;
+	char *buffer;
+	int nr, error;
+
+	/* Guess at some random initial size */
+	size = maxentries * 40;
+	buffer = git__malloc(size);
+	if (buffer == NULL)
+		return GIT_ENOMEM;
+		
+	offset = 0;
+	
+	for (nr = entry_no; nr < maxentries; ++nr) {
+		git_index_entry *entry = git_index_get(index, nr);
+
+		const char *pathname = entry->path, *filename, *dirname;
+		int pathlen = strlen(pathname), entrylen;
+
+		unsigned int write_mode;
+		git_oid subtree_oid;
+		git_oid *write_oid;
+		
+		/* Did we hit the end of the directory? Return how many we wrote */
+		if (baselen >= pathlen || memcmp(base, pathname, baselen) != 0)
+			break;
+		
+		/* Do we have _further_ subdirectories? */
+		filename = pathname + baselen;
+		dirname = strchr(filename, '/');
+
+		write_oid = &entry->oid;
+		write_mode = entry->mode;
+
+		if (dirname) {
+			int subdir_written;
+
+#if 0
+			if (entry->mode != S_IFDIR) {
+				free(buffer);
+				return GIT_EOBJCORRUPTED;
+			}
+#endif
+			subdir_written = write_index(&subtree_oid, index, pathname, dirname - pathname + 1, nr, maxentries);
+
+			if (subdir_written < GIT_SUCCESS) {
+				free(buffer);
+				return subdir_written;
+			}
+			
+			nr = subdir_written - 1;
+			
+			/* Now we need to write out the directory entry into this tree.. */
+			pathlen = dirname - pathname;
+			write_oid = &subtree_oid;
+			write_mode = S_IFDIR;
+		}
+
+		entrylen = pathlen - baselen;
+		if (offset + entrylen + 32 > size) {
+			size = alloc_nr(offset + entrylen + 32);
+			buffer = git__realloc(buffer, size);
+			
+			if (buffer == NULL)
+				return GIT_ENOMEM;
+		}
+
+		offset += write_index_entry(buffer + offset, write_mode, filename, entrylen, write_oid);
+	}
+	
+	error = git_odb_write(oid, index->repository->db, buffer, offset, GIT_OBJ_TREE);
+	free(buffer);
+
+	return (error == GIT_SUCCESS) ? nr : error;
+}
+
+int git_tree_create_fromindex(git_oid *oid, git_index *index)
+{
+	int error;
+
+	if (index->repository == NULL)
+		return GIT_EBAREINDEX;
+
+	error = write_index(oid, index, "", 0, 0, git_index_entrycount(index));
+	return (error < GIT_SUCCESS) ? error : GIT_SUCCESS;
+}
+
+static void sort_entries(git_treebuilder *bld)
+{
+	git_vector_sort(&bld->entries);
+}
+
+int git_treebuilder_create(git_treebuilder **builder_p, const git_tree *source)
+{
+	git_treebuilder *bld;
+	size_t i, source_entries = DEFAULT_TREE_SIZE;
+
+	assert(builder_p);
+
+	bld = git__calloc(1, sizeof(git_treebuilder));
+	if (bld == NULL)
+		return GIT_ENOMEM;
+
+	if (source != NULL)
+		source_entries = source->entries.length;
+
+	if (git_vector_init(&bld->entries, source_entries, entry_sort_cmp) < GIT_SUCCESS) {
+		free(bld);
+		return GIT_ENOMEM;
+	}
+
+	if (source != NULL) {
+		bld->entry_count = source_entries;
+		for (i = 0; i < source->entries.length; ++i) {
+			git_tree_entry *entry_src = source->entries.contents[i];
+			git_tree_entry *entry = git__calloc(1, sizeof(git_tree_entry));
+
+			if (entry == NULL) {
+				git_treebuilder_free(bld);
+				return GIT_ENOMEM;
+			}
+
+			entry->filename = git__strdup(entry_src->filename);
+
+			if (entry->filename == NULL) {
+				free(entry);
+				git_treebuilder_free(bld);
+				return GIT_ENOMEM;
+			}
+
+			entry->filename_len = entry_src->filename_len;
+			git_oid_cpy(&entry->oid, &entry_src->oid);
+			entry->attr = entry_src->attr;
+
+			git_vector_insert(&bld->entries, entry);
+		}
+	}
+
+	*builder_p = bld;
+	return GIT_SUCCESS;
+}
+
+int git_treebuilder_insert(git_tree_entry **entry_out, git_treebuilder *bld, const char *filename, const git_oid *id, unsigned int attributes)
+{
+	git_tree_entry *entry;
+	int pos;
+
+	assert(bld && id && filename);
+
+	if (!valid_attributes(attributes))
+		return GIT_ERROR;
+
+	if ((pos = git_vector_bsearch2(&bld->entries, entry_search_cmp, filename)) != GIT_ENOTFOUND) {
+		entry = git_vector_get(&bld->entries, pos);
+		if (entry->removed) {
+			entry->removed = 0;
+			bld->entry_count++;
+		}
+	} else {
+		if ((entry = git__malloc(sizeof(git_tree_entry))) == NULL)
+			return GIT_ENOMEM;
+
+		memset(entry, 0x0, sizeof(git_tree_entry));
+		entry->filename = git__strdup(filename);
+		entry->filename_len = strlen(entry->filename);
+
+		bld->entry_count++;
+	}
+
+	git_oid_cpy(&entry->oid, id);
+	entry->attr = attributes;
+
+	if (pos != GIT_ENOTFOUND) {
+		if (git_vector_insert(&bld->entries, entry) < 0)
+			return GIT_ENOMEM;
+	}
+
+	if (entry_out != NULL)
+		*entry_out = entry;
+
+	return GIT_SUCCESS;
+}
+
+const git_tree_entry *git_treebuilder_get(git_treebuilder *bld, const char *filename)
+{
+	int idx;
+	git_tree_entry *entry;
+
+	assert(bld && filename);
+
+	sort_entries(bld);
+	idx = git_vector_bsearch2(&bld->entries, entry_search_cmp, filename);
+	if (idx == GIT_ENOTFOUND)
+		return NULL;
+
+	entry = git_vector_get(&bld->entries, idx);
+	if (entry->removed)
+		return NULL;
+
+	return entry;
+}
+
+int git_treebuilder_remove(git_treebuilder *bld, const char *filename)
+{
+	git_tree_entry *remove_ptr = (git_tree_entry *)git_treebuilder_get(bld, filename);
+
+	if (remove_ptr == NULL || remove_ptr->removed)
+		return GIT_ENOTFOUND;
+
+	remove_ptr->removed = 1;
+	bld->entry_count--;
+	return GIT_SUCCESS;
+}
+
+int git_treebuilder_write(git_oid *oid, git_repository *repo, git_treebuilder *bld)
+{
+	size_t i, size = 0;
+	char filemode[MAX_FILEMODE_BYTES + 1 + 1];
+	git_odb_stream *stream;
+	int error;
+
+	assert(bld);
+
+	sort_entries(bld);
+
+	for (i = 0; i < bld->entries.length; ++i) {
+		git_tree_entry *entry = bld->entries.contents[i];
+
+		if (entry->removed)
+			continue;
+
+		size += (entry->attr > 0x7FF) ? 7 : 6;
+		size += entry->filename_len + 1;
+		size += GIT_OID_RAWSZ;
+	}
+
+	if ((error = git_odb_open_wstream(&stream, git_repository_database(repo), size, GIT_OBJ_TREE)) < GIT_SUCCESS)
+		return error;
+
+	for (i = 0; i < bld->entries.length; ++i) {
+		git_tree_entry *entry = bld->entries.contents[i];
+
+		if (entry->removed)
+			continue;
+
+		snprintf(filemode, sizeof(filemode), "%o ", entry->attr);
+		stream->write(stream, filemode, strlen(filemode));
+		stream->write(stream, entry->filename, entry->filename_len + 1);
+		stream->write(stream, (char *)entry->oid.id, GIT_OID_RAWSZ);
+	} 
+
+	error = stream->finalize_write(oid, stream);
+	stream->free(stream);
+
+	return error;
+}
+
+void git_treebuilder_filter(git_treebuilder *bld, int (*filter)(const git_tree_entry *, void *), void *payload)
+{
+	size_t i;
+
+	assert(bld && filter);
+
+	for (i = 0; i < bld->entries.length; ++i) {
+		git_tree_entry *entry = bld->entries.contents[i];
+		if (!entry->removed && filter(entry, payload))
+			entry->removed = 1;
+	}
+}
+
+void git_treebuilder_clear(git_treebuilder *bld)
+{
+	size_t i;
+	assert(bld);
+
+	for (i = 0; i < bld->entries.length; ++i) {
+		git_tree_entry *e = bld->entries.contents[i];
+		free(e->filename);
+		free(e);
+	}
+
+	git_vector_clear(&bld->entries);
+}
+
+void git_treebuilder_free(git_treebuilder *bld)
+{
+	git_treebuilder_clear(bld);
+	git_vector_free(&bld->entries);
+	free(bld);
+}
+
+
diff --git a/src/tree.h b/src/tree.h
index b4e910a..bff3f8e 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -10,6 +10,8 @@ struct git_tree_entry {
 	unsigned int attr;
 	char *filename;
 	git_oid oid;
+	size_t filename_len;
+	int removed;
 };
 
 struct git_tree {
@@ -17,6 +19,12 @@ struct git_tree {
 	git_vector entries;
 };
 
+struct git_treebuilder {
+	git_vector entries;
+	size_t entry_count;
+};
+
+
 void git_tree__free(git_tree *tree);
 int git_tree__parse(git_tree *tree, git_odb_object *obj);
 
diff --git a/src/util.h b/src/util.h
index 653b34d..f477b64 100644
--- a/src/util.h
+++ b/src/util.h
@@ -14,6 +14,7 @@
  */
 #define git__malloc malloc
 #define git__calloc calloc
+#define git__realloc realloc
 #define git__strdup strdup
 
 extern int git__fmt(char *, size_t, const char *, ...)
diff --git a/tests/resources/testrepo.git/refs/tags/e90810b b/tests/resources/testrepo.git/refs/tags/e90810b
new file mode 100644
index 0000000..584495d
--- /dev/null
+++ b/tests/resources/testrepo.git/refs/tags/e90810b
@@ -0,0 +1 @@
+7b4384978d2493e851f9cca7858815fac9b10980
diff --git a/tests/resources/testrepo.git/refs/tags/very-simple b/tests/resources/testrepo.git/refs/tags/very-simple
deleted file mode 100644
index 584495d..0000000
--- a/tests/resources/testrepo.git/refs/tags/very-simple
+++ /dev/null
@@ -1 +0,0 @@
-7b4384978d2493e851f9cca7858815fac9b10980
diff --git a/tests/t04-commit.c b/tests/t04-commit.c
index e928424..bcc0417 100644
--- a/tests/t04-commit.c
+++ b/tests/t04-commit.c
@@ -114,15 +114,15 @@ BEGIN_TEST(parse0, "parse the OID line in a commit")
 	git_oid oid;
 
 #define TEST_OID_PASS(string, header) { \
-	char *ptr = string;\
-	char *ptr_original = ptr;\
+	const char *ptr = string;\
+	const char *ptr_original = ptr;\
 	size_t len = strlen(ptr);\
 	must_pass(git__parse_oid(&oid, &ptr, ptr + len, header));\
 	must_be_true(ptr == ptr_original + len);\
 }
 
 #define TEST_OID_FAIL(string, header) { \
-	char *ptr = string;\
+	const char *ptr = string;\
 	size_t len = strlen(ptr);\
 	must_fail(git__parse_oid(&oid, &ptr, ptr + len, header));\
 }
@@ -154,7 +154,7 @@ END_TEST
 BEGIN_TEST(parse1, "parse the signature line in a commit")
 
 #define TEST_SIGNATURE_PASS(_string, _header, _name, _email, _time, _offset) { \
-	char *ptr = _string; \
+	const char *ptr = _string; \
 	size_t len = strlen(_string);\
 	git_signature person = {NULL, NULL, {0, 0}}; \
 	must_pass(git_signature__parse(&person, &ptr, ptr + len, _header));\
@@ -166,7 +166,7 @@ BEGIN_TEST(parse1, "parse the signature line in a commit")
 }
 
 #define TEST_SIGNATURE_FAIL(_string, _header) { \
-	char *ptr = _string; \
+	const char *ptr = _string; \
 	size_t len = strlen(_string);\
 	git_signature person = {NULL, NULL, {0, 0}}; \
 	must_fail(git_signature__parse(&person, &ptr, ptr + len, _header));\
diff --git a/tests/t08-tag.c b/tests/t08-tag.c
index 70eeb28..e701648 100644
--- a/tests/t08-tag.c
+++ b/tests/t08-tag.c
@@ -58,6 +58,9 @@ BEGIN_TEST(read0, "read and parse a tag from the repository")
 
 	must_be_true(git_oid_cmp(&id_commit, git_commit_id(commit)) == 0);
 
+	git_tag_close(tag1);
+	git_tag_close(tag2);
+	git_commit_close(commit);
 	git_repository_free(repo);
 END_TEST
 
@@ -72,20 +75,19 @@ BEGIN_TEST(write0, "write a tag to the repository and read it again")
 	git_oid target_id, tag_id;
 	const git_signature *tagger;
 	git_reference *ref_tag;
-	/* char hex_oid[41]; */
 
 	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
 
 	git_oid_mkstr(&target_id, tagged_commit);
 
-	/* create signatures */
+	/* create signature */
 	tagger = git_signature_new(TAGGER_NAME, TAGGER_EMAIL, 123456789, 60);
 	must_be_true(tagger != NULL);
 
 	must_pass(git_tag_create(
 		&tag_id, /* out id */
 		repo,
-		"the-tag", /* do not update the HEAD */
+		"the-tag",
 		&target_id,
 		GIT_OBJ_COMMIT,
 		tagger,
@@ -94,6 +96,7 @@ BEGIN_TEST(write0, "write a tag to the repository and read it again")
 	git_signature_free((git_signature *)tagger);
 
 	must_pass(git_tag_lookup(&tag, repo, &tag_id));
+	must_be_true(git_oid_cmp(git_tag_target_oid(tag), &target_id) == 0);
 
 	/* Check attributes were set correctly */
 	tagger = git_tag_tagger(tag);
@@ -111,12 +114,136 @@ BEGIN_TEST(write0, "write a tag to the repository and read it again")
 
 	must_pass(remove_loose_object(REPOSITORY_FOLDER, (git_object *)tag));
 
+	git_tag_close(tag);
 	git_repository_free(repo);
 
 END_TEST
 
+BEGIN_TEST(write1, "write a tag to the repository which points to an unknown oid and read it again")
+	git_repository *repo;
+	git_tag *tag;
+	git_oid target_id, tag_id;
+	const git_signature *tagger;
+	git_reference *ref_tag;
+	git_object *zombie;
+
+	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
+
+	git_oid_mkstr(&target_id, "deadbeef1b46c854b31185ea97743be6a8774479");
+
+	/* create signature */
+	tagger = git_signature_new(TAGGER_NAME, TAGGER_EMAIL, 123456789, 60);
+	must_be_true(tagger != NULL);
+
+	must_pass(git_tag_create(
+		&tag_id, /* out id */
+		repo,
+		"the-zombie-tag",
+		&target_id,
+		GIT_OBJ_COMMIT,
+		tagger,
+		TAGGER_MESSAGE));
+
+	git_signature_free((git_signature *)tagger);
+
+	must_pass(git_tag_lookup(&tag, repo, &tag_id));
+	
+	/* The non existent target can not be looked up */
+	must_fail(git_tag_target(&zombie, tag));
+
+	must_pass(git_reference_lookup(&ref_tag, repo, "refs/tags/the-zombie-tag"));
+	
+	must_pass(git_reference_delete(ref_tag));
+	must_pass(remove_loose_object(REPOSITORY_FOLDER, (git_object *)tag));
+
+	git_tag_close(tag);
+	git_repository_free(repo);
+
+END_TEST
+
+BEGIN_TEST(write2, "Attempt to write a tag bearing the same name than an already existing tag")
+	git_repository *repo;
+	git_oid target_id, tag_id;
+	const git_signature *tagger;
+
+	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
+
+	git_oid_mkstr(&target_id, tagged_commit);
+
+	/* create signature */
+	tagger = git_signature_new(TAGGER_NAME, TAGGER_EMAIL, 123456789, 60);
+	must_be_true(tagger != NULL);
+
+	must_fail(git_tag_create(
+		&tag_id, /* out id */
+		repo,
+		"e90810b",
+		&target_id,
+		GIT_OBJ_COMMIT,
+		tagger,
+		TAGGER_MESSAGE));
+
+	git_signature_free((git_signature *)tagger);
+
+	git_repository_free(repo);
+
+END_TEST
+
+BEGIN_TEST(write3, "Replace an already existing tag")
+	git_repository *repo;
+	git_oid target_id, tag_id, old_tag_id;
+	const git_signature *tagger;
+	git_reference *ref_tag;
+
+	must_pass(open_temp_repo(&repo, REPOSITORY_FOLDER));
+
+	git_oid_mkstr(&target_id, tagged_commit);
+
+	must_pass(git_reference_lookup(&ref_tag, repo, "refs/tags/e90810b"));
+	git_oid_cpy(&old_tag_id, git_reference_oid(ref_tag));
+
+	/* create signature */
+	tagger = git_signature_new(TAGGER_NAME, TAGGER_EMAIL, 123456789, 60);
+	must_be_true(tagger != NULL);
+
+	must_pass(git_tag_create_f(
+		&tag_id, /* out id */
+		repo,
+		"e90810b",
+		&target_id,
+		GIT_OBJ_COMMIT,
+		tagger,
+		TAGGER_MESSAGE));
+
+	git_signature_free((git_signature *)tagger);
+
+	must_pass(git_reference_lookup(&ref_tag, repo, "refs/tags/e90810b"));
+	must_be_true(git_oid_cmp(git_reference_oid(ref_tag), &tag_id) == 0);
+	must_be_true(git_oid_cmp(git_reference_oid(ref_tag), &old_tag_id) != 0);
+
+	close_temp_repo(repo);
+
+END_TEST
+
+BEGIN_TEST(write4, "Delete an already existing tag")
+	git_repository *repo;
+	git_reference *ref_tag;
+
+	must_pass(open_temp_repo(&repo, REPOSITORY_FOLDER));
+
+	must_pass(git_tag_delete(repo,"e90810b"));
+
+	must_fail(git_reference_lookup(&ref_tag, repo, "refs/tags/e90810b"));
+
+	close_temp_repo(repo);
+
+END_TEST
 
 BEGIN_SUITE(tag)
 	ADD_TEST(read0);
-	ADD_TEST(write0); 
+	ADD_TEST(write0);
+	ADD_TEST(write1);
+	ADD_TEST(write2);
+	ADD_TEST(write3);
+	ADD_TEST(write4);
 END_SUITE
diff --git a/tests/t09-tree.c b/tests/t09-tree.c
index 6c1b2e6..e4252db 100644
--- a/tests/t09-tree.c
+++ b/tests/t09-tree.c
@@ -29,6 +29,36 @@
 
 static const char *tree_oid = "1810dff58d8a660512d4832e740f692884338ccd";
 
+#if 0
+static int print_tree(git_repository *repo, const git_oid *tree_oid, int depth)
+{
+	static const char *indent = "                              ";
+	git_tree *tree;
+	unsigned int i;
+
+	if (git_tree_lookup(&tree, repo, tree_oid) < GIT_SUCCESS)
+		return GIT_ERROR;
+
+	for (i = 0; i < git_tree_entrycount(tree); ++i) {
+		const git_tree_entry *entry = git_tree_entry_byindex(tree, i);
+		char entry_oid[40];
+
+		git_oid_fmt(entry_oid, &entry->oid);
+		printf("%.*s%o [%.*s] %s\n", depth*2, indent, entry->attr, 40, entry_oid, entry->filename);
+
+		if (entry->attr == S_IFDIR) {
+			if (print_tree(repo, &entry->oid, depth + 1) < GIT_SUCCESS) {
+				git_tree_close(tree);
+				return GIT_ERROR;
+			}
+		}
+	}
+
+	git_tree_close(tree);
+	return GIT_SUCCESS;
+}
+#endif
+
 BEGIN_TEST(read0, "acces randomly the entries on a loaded tree")
 	git_oid id;
 	git_repository *repo;
@@ -55,7 +85,7 @@ BEGIN_TEST(read1, "read a tree from the repository")
 	git_oid id;
 	git_repository *repo;
 	git_tree *tree;
-	git_tree_entry *entry;
+	const git_tree_entry *entry;
 	git_object *obj;
 
 	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
@@ -80,10 +110,27 @@ BEGIN_TEST(read1, "read a tree from the repository")
 	git_repository_free(repo);
 END_TEST
 
+#if 0
+BEGIN_TEST(write0, "write a tree from an index")
+	git_repository *repo;
+	git_index *index;
+	git_oid tree_oid;
+
+	must_pass(git_repository_open(&repo, "/tmp/redtmp/.git"));
+	must_pass(git_repository_index(&index, repo));
+
+	must_pass(git_tree_create_fromindex(&tree_oid, index));
+	must_pass(print_tree(repo, &tree_oid, 0));
+
+	git_repository_free(repo);
+END_TEST
+#endif
+
 BEGIN_SUITE(tree)
+	//ADD_TEST(print0);
 	ADD_TEST(read0);
 	ADD_TEST(read1);
-//	ADD_TEST(write0); /* TODO THREADSAFE */
-//	ADD_TEST(write1);
+	//ADD_TEST(write0);
+	//ADD_TEST(write1);
 END_SUITE
 
diff --git a/tests/t10-refs.c b/tests/t10-refs.c
index 413811c..2797cd8 100644
--- a/tests/t10-refs.c
+++ b/tests/t10-refs.c
@@ -27,13 +27,14 @@
 
 #include "repository.h"
 
-static const char *loose_tag_ref_name = "refs/tags/test";
+static const char *loose_tag_ref_name = "refs/tags/e90810b";
 static const char *non_existing_tag_ref_name = "refs/tags/i-do-not-exist";
 
 BEGIN_TEST(readtag0, "lookup a loose tag reference")
 	git_repository *repo;
 	git_reference *reference;
 	git_object *object;
+	char ref_name_from_tag_name[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
 
 	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
 
@@ -46,6 +47,10 @@ BEGIN_TEST(readtag0, "lookup a loose tag reference")
 	must_be_true(object != NULL);
 	must_be_true(git_object_type(object) == GIT_OBJ_TAG);
 
+	/* Ensure the name of the tag matches the name of the reference */
+	git__joinpath(ref_name_from_tag_name, GIT_REFS_TAGS_DIR, git_tag_name((git_tag *)object));
+	must_be_true(strcmp(ref_name_from_tag_name, loose_tag_ref_name) == 0);
+
 	git_repository_free(repo);
 END_TEST
 
@@ -227,9 +232,8 @@ BEGIN_TEST(create0, "create a new symbolic reference")
 	must_pass(git_reference_resolve(&resolved_ref, looked_up_ref));
 	must_be_true(git_oid_cmp(&id, git_reference_oid(resolved_ref)) == 0);
 
+	git_reference_delete(looked_up_ref);
 	git_repository_free(repo);
-
-	must_pass(gitfo_unlink(ref_path));	/* TODO: replace with git_reference_delete() when available */
 END_TEST
 
 BEGIN_TEST(create1, "create a deep symbolic reference")
@@ -250,9 +254,8 @@ BEGIN_TEST(create1, "create a deep symbolic reference")
 	must_pass(git_reference_resolve(&resolved_ref, looked_up_ref));
 	must_be_true(git_oid_cmp(&id, git_reference_oid(resolved_ref)) == 0);
 
+	git_reference_delete(looked_up_ref);
 	git_repository_free(repo);
-
-	must_pass(gitfo_unlink(ref_path));	/* TODO: replace with git_reference_delete() when available */
 END_TEST
 
 BEGIN_TEST(create2, "create a new OID reference")
@@ -290,9 +293,28 @@ BEGIN_TEST(create2, "create a new OID reference")
 	must_pass(git_reference_lookup(&looked_up_ref, repo, new_head));
 	must_be_true(git_oid_cmp(&id, git_reference_oid(looked_up_ref)) == 0);
 
+	git_reference_delete(looked_up_ref);
 	git_repository_free(repo);
+END_TEST
 
-	must_pass(gitfo_unlink(ref_path));	/* TODO: replace with git_reference_delete() when available */
+BEGIN_TEST(create3, "Can not create a new OID reference which targets at an unknown id")
+	git_reference *new_reference, *looked_up_ref;
+	git_repository *repo;
+	git_oid id;
+
+	const char *new_head = "refs/heads/new-head";
+
+	git_oid_mkstr(&id, "deadbeef3f795b2b4353bcce3a527ad0a4f7f644");
+
+	must_pass(git_repository_open(&repo, REPOSITORY_FOLDER));
+
+	/* Create and write the new object id reference */
+	must_fail(git_reference_create_oid(&new_reference, repo, new_head, &id));
+
+	/* Ensure the reference can't be looked-up... */
+	must_fail(git_reference_lookup(&looked_up_ref, repo, new_head));
+
+	git_repository_free(repo);
 END_TEST
 
 static const char *ref_name = "refs/heads/other";
@@ -892,6 +914,7 @@ BEGIN_SUITE(refs)
 	ADD_TEST(create0);
 	ADD_TEST(create1);
 	ADD_TEST(create2);
+	ADD_TEST(create3);
 
 	ADD_TEST(overwrite0);
 	ADD_TEST(overwrite1);
diff --git a/wscript b/wscript
index f3082ae..dd90406 100644
--- a/wscript
+++ b/wscript
@@ -4,7 +4,7 @@ from waflib.Build import BuildContext, CleanContext, \
 
 # Unix flags
 CFLAGS_UNIX = ["-O2", "-Wall", "-Wextra"]
-CFLAGS_UNIX_DBG = ['-g']
+CFLAGS_UNIX_DBG = ['-g', '-O0']
 
 # Windows MSVC flags
 CFLAGS_WIN32_COMMON = ['/TC', '/W4', '/WX', '/nologo', '/Zi']