Some coverity inspired cleanups

src/config.c

@@ -153,19 +153,19 @@ int git_config_snapshot(git_config **out, git_config *in)
 		git_config_backend *b;
 
 		if ((error = internal->file->snapshot(&b, internal->file)) < 0)
-			goto on_error;
+			break;
 
 		if ((error = git_config_add_backend(config, b, internal->level, 0)) < 0) {
 			b->free(b);
-			goto on_error;
+			break;
 		}
 	}
 
-	*out = config;
-	return error;
+	if (error < 0)
+		git_config_free(config);
+	else
+		*out = config;
 
-on_error:
-	git_config_free(config);
 	return error;
 }
 

src/config_file.c

@@ -313,6 +313,7 @@ static int config__refresh(git_config_backend *cfg)
 		goto out;
 
 	reader = git_array_get(b->readers, git_array_size(b->readers) - 1);
+	GITERR_CHECK_ALLOC(reader);
 
 	if ((error = config_parse(values->values, b, reader, b->level, 0)) < 0)
 		goto out;
@@ -327,7 +328,8 @@ static int config__refresh(git_config_backend *cfg)
 
 out:
 	refcounted_strmap_free(values);
-	git_buf_free(&reader->buffer);
+	if (reader)
+		git_buf_free(&reader->buffer);
 	return error;
 }
 
@@ -344,8 +346,8 @@ static int config_refresh(git_config_backend *cfg)
 			&reader->buffer, reader->file_path,
 			&reader->file_mtime, &reader->file_size, &updated);
 
-		if (error < 0)
-			return (error == GIT_ENOTFOUND) ? 0 : error;
+		if (error < 0 && error != GIT_ENOTFOUND)
+			return error;
 
 		if (updated)
 			any_updated = 1;

src/diff_driver.c

@@ -233,17 +233,17 @@ static int git_diff_driver_load(
 		return 0;
 	}
 
+	drv = git__calloc(1, sizeof(git_diff_driver) + namelen + 1);
+	GITERR_CHECK_ALLOC(drv);
+	drv->type = DIFF_DRIVER_AUTO;
+	memcpy(drv->name, driver_name, namelen);
+
 	/* if you can't read config for repo, just use default driver */
 	if (git_repository_config_snapshot(&cfg, repo) < 0) {
 		giterr_clear();
 		goto done;
 	}
 
-	drv = git__calloc(1, sizeof(git_diff_driver) + namelen + 1);
-	GITERR_CHECK_ALLOC(drv);
-	drv->type = DIFF_DRIVER_AUTO;
-	memcpy(drv->name, driver_name, namelen);
-
 	if ((error = git_buf_printf(&name, "diff.%s.binary", driver_name)) < 0)
 		goto done;
 

src/tag.c

@@ -363,20 +363,22 @@ int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *bu
 	}
 
 	/* write the buffer */
-	if (git_odb_open_wstream(&stream, odb, strlen(buffer), GIT_OBJ_TAG) < 0)
-		return -1;
+	if ((error = git_odb_open_wstream(
+			&stream, odb, strlen(buffer), GIT_OBJ_TAG)) < 0)
+		return error;
 
-	git_odb_stream_write(stream, buffer, strlen(buffer));
+	if (!(error = git_odb_stream_write(stream, buffer, strlen(buffer))))
+		error = git_odb_stream_finalize_write(oid, stream);
 
-	error = git_odb_stream_finalize_write(oid, stream);
 	git_odb_stream_free(stream);
 
 	if (error < 0) {
 		git_buf_free(&ref_name);
-		return -1;
+		return error;
 	}
 
-	error = git_reference_create(&new_ref, repo, ref_name.ptr, oid, allow_ref_overwrite, NULL, NULL);
+	error = git_reference_create(
+		&new_ref, repo, ref_name.ptr, oid, allow_ref_overwrite, NULL, NULL);
 
 	git_reference_free(new_ref);
 	git_buf_free(&ref_name);