git_libgit2_opts: introduce `GIT_OPT_ENABLE_STRICT_OBJECT_CREATION`

include/git2/common.h

@@ -147,6 +147,7 @@ typedef enum {
 	GIT_OPT_SET_TEMPLATE_PATH,
 	GIT_OPT_SET_SSL_CERT_LOCATIONS,
 	GIT_OPT_SET_USER_AGENT,
+	GIT_OPT_ENABLE_STRICT_OBJECT_CREATION,
 } git_libgit2_opt_t;
 
 /**
@@ -251,6 +252,14 @@ typedef enum {
  *		> - `user_agent` is the value that will be delivered as the
  *		>   User-Agent header on HTTP requests.
  *
+ *	* opts(GIT_OPT_ENABLE_STRICT_OBJECT_CREATION, int enabled)
+ *
+ *		> Enable strict input validation when creating new objects
+ *		> to ensure that all inputs to the new objects are valid.  For
+ *		> example, when this is enabled, the parent(s) and tree inputs
+ *		> will be validated when creating a new commit.  This defaults
+ *		> to disabled.
+ *
  * @param option Option key
  * @param ... value to set the option
  * @return 0 on success, <0 on failure

src/object.c

@@ -14,6 +14,8 @@
 #include "blob.h"
 #include "tag.h"
 
+bool git_object__strict_input_validation = false;
+
 typedef struct {
 	const char	*str;	/* type name string */
 	size_t		size;	/* size in bytes of the object structure */

src/object.h

@@ -7,6 +7,8 @@
 #ifndef INCLUDE_object_h__
 #define INCLUDE_object_h__
 
+extern bool git_object__strict_input_validation;
+
 /** Base git object for inheritance */
 struct git_object {
 	git_cached_obj cached;

src/settings.c

@@ -14,6 +14,7 @@
 #include "sysdir.h"
 #include "cache.h"
 #include "global.h"
+#include "object.h"
 
 void git_libgit2_version(int *major, int *minor, int *rev)
 {
@@ -181,6 +182,11 @@ int git_libgit2_opts(int key, ...)
 		}
 
 		break;
+
+	case GIT_OPT_ENABLE_STRICT_OBJECT_CREATION:
+		git_object__strict_input_validation = (va_arg(ap, int) != 0);
+		break;
+
 	default:
 		giterr_set(GITERR_INVALID, "invalid option key");
 		error = -1;