test: improve coverage

lib/src/bindings/diff.dart

@@ -21,7 +21,16 @@ Pointer<git_diff> indexToWorkdir({
     interhunkLines: interhunkLines,
   );
 
-  libgit2.git_diff_index_to_workdir(out, repoPointer, indexPointer, opts);
+  final error = libgit2.git_diff_index_to_workdir(
+    out,
+    repoPointer,
+    indexPointer,
+    opts,
+  );
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
 
   calloc.free(opts);
 
@@ -46,7 +55,7 @@ Pointer<git_diff> treeToIndex({
     interhunkLines: interhunkLines,
   );
 
-  libgit2.git_diff_tree_to_index(
+  final error = libgit2.git_diff_tree_to_index(
     out,
     repoPointer,
     treePointer,
@@ -54,6 +63,10 @@ Pointer<git_diff> treeToIndex({
     opts,
   );
 
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+
   calloc.free(opts);
 
   return out.value;
@@ -76,7 +89,16 @@ Pointer<git_diff> treeToWorkdir({
     interhunkLines: interhunkLines,
   );
 
-  libgit2.git_diff_tree_to_workdir(out, repoPointer, treePointer, opts);
+  final error = libgit2.git_diff_tree_to_workdir(
+    out,
+    repoPointer,
+    treePointer,
+    opts,
+  );
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
 
   calloc.free(opts);
 
@@ -101,7 +123,7 @@ Pointer<git_diff> treeToTree({
     interhunkLines: interhunkLines,
   );
 
-  libgit2.git_diff_tree_to_tree(
+  final error = libgit2.git_diff_tree_to_tree(
     out,
     repoPointer,
     oldTreePointer,
@@ -109,6 +131,10 @@ Pointer<git_diff> treeToTree({
     opts,
   );
 
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+
   calloc.free(opts);
 
   return out.value;
@@ -351,15 +377,18 @@ Pointer<git_diff_options> _diffOptionsInit({
   required int interhunkLines,
 }) {
   final opts = calloc<git_diff_options>();
-  final optsError =
-      libgit2.git_diff_options_init(opts, GIT_DIFF_OPTIONS_VERSION);
-  opts.ref.flags = flags;
-  opts.ref.context_lines = contextLines;
-  opts.ref.interhunk_lines = interhunkLines;
+  final optsError = libgit2.git_diff_options_init(
+    opts,
+    GIT_DIFF_OPTIONS_VERSION,
+  );
 
   if (optsError < 0) {
+    calloc.free(opts);
     throw LibGit2Error(libgit2.git_error_last());
   } else {
+    opts.ref.flags = flags;
+    opts.ref.context_lines = contextLines;
+    opts.ref.interhunk_lines = interhunkLines;
     return opts;
   }
 }

lib/src/bindings/merge.dart

@@ -120,16 +120,16 @@ void merge({
 String mergeFileFromIndex({
   required Pointer<git_repository> repoPointer,
   required Pointer<git_index_entry>? ancestorPointer,
-  required Pointer<git_index_entry>? oursPointer,
-  required Pointer<git_index_entry>? theirsPointer,
+  required Pointer<git_index_entry> oursPointer,
+  required Pointer<git_index_entry> theirsPointer,
 }) {
   final out = calloc<git_merge_file_result>();
   final error = libgit2.git_merge_file_from_index(
     out,
     repoPointer,
     ancestorPointer ?? nullptr,
-    oursPointer ?? nullptr,
-    theirsPointer ?? nullptr,
+    oursPointer,
+    theirsPointer,
     nullptr,
   );
 

lib/src/bindings/reference.dart

@@ -235,6 +235,8 @@ bool isTag(Pointer<git_reference> ref) {
 ///
 /// The message for the reflog will be ignored if the reference does not belong in the
 /// standard set (HEAD, branches and remote-tracking branches) and it does not have a reflog.
+///
+/// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> createDirect({
   required Pointer<git_repository> repoPointer,
   required String name,
@@ -288,6 +290,8 @@ Pointer<git_reference> createDirect({
 ///
 /// The message for the reflog will be ignored if the reference does not belong in the standard
 /// set (HEAD, branches and remote-tracking branches) and it does not have a reflog.
+///
+/// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> createSymbolic({
   required Pointer<git_repository> repoPointer,
   required String name,

lib/src/bindings/tree.dart

@@ -73,7 +73,7 @@ Pointer<git_tree_entry> getByName({
 /// Retrieve a tree entry contained in a tree or in any of its subtrees, given its relative path.
 ///
 /// Unlike the other lookup functions, the returned tree entry is owned by the user and must be
-/// freed explicitly with `entryFree()`.
+/// freed explicitly with [entryFree].
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_tree_entry> getByPath({
@@ -122,7 +122,7 @@ int compare({
 /// Free a user-owned tree entry.
 ///
 /// IMPORTANT: This function is only needed for tree entries owned by the user,
-/// such as `getByPath()`.
+/// such as [getByPath].
 void entryFree(Pointer<git_tree_entry> entry) =>
     libgit2.git_tree_entry_free(entry);