diff --git a/src/cli/cmd.h b/src/cli/cmd.h
index bce4709fb..0ab237aa2 100644
--- a/src/cli/cmd.h
+++ b/src/cli/cmd.h
@@ -28,6 +28,7 @@ extern const cli_cmd_spec *cli_cmd_spec_byname(const char *name);
 extern int cmd_blame(int argc, char **argv);
 extern int cmd_cat_file(int argc, char **argv);
 extern int cmd_clone(int argc, char **argv);
+extern int cmd_commit(int argc, char **argv);
 extern int cmd_config(int argc, char **argv);
 extern int cmd_hash_object(int argc, char **argv);
 extern int cmd_help(int argc, char **argv);
diff --git a/src/cli/cmd_blame.c b/src/cli/cmd_blame.c
index 180a948f9..620bd9ca1 100644
--- a/src/cli/cmd_blame.c
+++ b/src/cli/cmd_blame.c
@@ -70,7 +70,7 @@ static int fmt_date(git_str *out, git_time_t time, int offset)
 	time_t t;
 	struct tm gmt;
 
-	GIT_ASSERT_ARG(out);
+	CLI_ASSERT(out);
 
 	t = (time_t)(time + offset * 60);
 
diff --git a/src/cli/cmd_cat_file.c b/src/cli/cmd_cat_file.c
index 95a0240ca..693a4e303 100644
--- a/src/cli/cmd_cat_file.c
+++ b/src/cli/cmd_cat_file.c
@@ -91,7 +91,7 @@ static int print_odb(git_object *object, display_t display)
 			ret = cli_error_os();
 		break;
 	default:
-		GIT_ASSERT(0);
+		CLI_ASSERT(!"invalid display type");
 	}
 
 done:
diff --git a/src/cli/cmd_commit.c b/src/cli/cmd_commit.c
new file mode 100644
index 000000000..e0641a171
--- /dev/null
+++ b/src/cli/cmd_commit.c
@@ -0,0 +1,621 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include <git2.h>
+#include "common.h"
+#include "cmd.h"
+#include "futils.h"
+#include "process.h"
+
+#define COMMAND_NAME "commit"
+
+static char unset_keyid[] = { 0 };
+
+static char *message;
+static char *template;
+static int amend;
+static int allow_empty;
+static int allow_empty_message;
+static char *keyid = unset_keyid;
+static int no_sign;
+
+static const cli_opt_spec opts[] = {
+	CLI_COMMON_OPT,
+
+	{ CLI_OPT_TYPE_VALUE,     NULL,                 'm', &message,             0,
+	  CLI_OPT_USAGE_DEFAULT, "message",             "specify the commit message" },
+	{ CLI_OPT_TYPE_VALUE,    "template",            't', &template,            0,
+	  CLI_OPT_USAGE_DEFAULT, "file",                "the original text for the commit message" },
+
+	{ CLI_OPT_TYPE_SWITCH,   "amend",                0,  &amend,               1,
+	  0,                      NULL,                 "allow commits that have no changes" },
+
+	{ CLI_OPT_TYPE_SWITCH,   "allow-empty",          0,  &allow_empty,         1,
+	  0,                      NULL,                 "allow commits that have no changes" },
+	{ CLI_OPT_TYPE_SWITCH,   "allow-empty-message",  0,  &allow_empty_message, 1,
+	  0,                      NULL,                 "allow commit message" },
+
+	{ CLI_OPT_TYPE_VALUE,    "gpg-sign",            'S', &keyid,               0,
+	  CLI_OPT_USAGE_VALUE_OPTIONAL, "keyid",        "sign the commit" },
+	{ CLI_OPT_TYPE_SWITCH,   "no-gpg-sign",          0,  &no_sign,             1,
+	  CLI_OPT_USAGE_CHOICE,   NULL,                 "do not sign the commit" },
+
+	{ 0 },
+};
+
+#define MESSAGE_INSTRUCTIONS \
+	"# Please enter the commit message for your changes. Lines starting\n" \
+	"# with '#' will be ignored, and an empty message aborts the commit.\n"
+
+static void print_help(void)
+{
+	cli_opt_usage_fprint(stdout, PROGRAM_NAME, COMMAND_NAME, opts, 0);
+	printf("\n");
+
+	printf("Commit the current contents of the index.\n");
+	printf("\n");
+
+	printf("Options:\n");
+
+	cli_opt_help_fprint(stdout, opts);
+}
+
+static int check_empty_commit(git_status_list *status)
+{
+	const git_status_entry *entry;
+	size_t entries, i;
+
+	if (amend || allow_empty)
+		return 0;
+
+	entries = git_status_list_entrycount(status);
+
+	for (i = 0; i < entries; i++) {
+		entry = git_status_byindex(status, i);
+
+		if (entry->head_to_index != NULL)
+			return 0;
+	}
+
+	return cli_error("no changes added to commit (use \"git add\" and/or \"git commit -a\")");
+}
+
+static int prepare_amend_message(
+	git_str *message,
+	git_reference *head_ref)
+{
+	git_commit *head_commit;
+	int ret = 0;
+
+	if (git_reference_peel((git_object **)&head_commit, head_ref, GIT_OBJECT_COMMIT) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	git_str_puts(message, git_commit_message(head_commit));
+
+done:
+	git_commit_free(head_commit);
+	return ret;
+}
+
+static int prepare_template(git_str *message, git_repository *repo)
+{
+	git_config *config = NULL;
+	git_buf config_value = GIT_BUF_INIT;
+	int error, ret = 0;
+
+	if (!template) {
+		if (git_repository_config(&config, repo) < 0) {
+			ret = cli_error_git();
+			goto done;
+		}
+
+		error = git_config_get_string_buf(&config_value,
+			config, "commit.template");
+
+		if (error && error != GIT_ENOTFOUND) {
+			ret = cli_error_git();
+			goto done;
+		} else if (error != GIT_ENOTFOUND) {
+			template = config_value.ptr;
+		}
+	}
+
+	if (template) {
+		if (git_futils_readbuffer(message, template) < 0) {
+			ret = cli_error_git();
+			goto done;
+		}
+	}
+
+done:
+	git_buf_dispose(&config_value);
+	git_config_free(config);
+	return ret;
+}
+
+static int prepare_changes(
+	git_str *message,
+	git_status_list *status)
+{
+	const git_status_entry *entry;
+	const git_diff_delta *delta;
+	const char *change_type, *file;
+	bool staged_header = false, unstaged_header = false,
+	     untracked_header = false;
+	size_t entries, i;
+
+	entries = git_status_list_entrycount(status);
+
+	for (i = 0; i < entries; i++) {
+		entry = git_status_byindex(status, i);
+
+		if (!(delta = entry->head_to_index))
+			continue;
+
+		if (!staged_header) {
+			git_str_puts(message, "# Changes to be committed:\n");
+			staged_header = true;
+		}
+
+		switch (delta->status) {
+		case GIT_DELTA_ADDED:
+			change_type = "new file:";
+			file = delta->new_file.path;
+			break;
+		case GIT_DELTA_DELETED:
+			change_type = "deleted:";
+			file = delta->old_file.path;
+			break;
+		case GIT_DELTA_MODIFIED:
+			change_type = "modified:";
+			file = delta->old_file.path;
+			break;
+		case GIT_DELTA_RENAMED:
+			change_type = "renamed:";
+			file = delta->old_file.path;
+			break;
+		default:
+			CLI_ASSERT(!"unhandled head->index delta type");
+			break;
+		}
+
+
+		git_str_printf(message, "#\t%-11s %s", change_type, file);
+
+		if (delta->status == GIT_DELTA_RENAMED)
+			git_str_printf(message, " -> %s", delta->new_file.path);
+
+		git_str_printf(message, "\n");
+	}
+
+	for (i = 0; i < entries; i++) {
+		entry = git_status_byindex(status, i);
+
+		if (!(delta = entry->index_to_workdir) ||
+		    delta->status == GIT_DELTA_UNTRACKED)
+			continue;
+
+		if (!unstaged_header) {
+			if (staged_header)
+				git_str_puts(message, "#\n");
+
+			git_str_puts(message, "# Changes not staged for commit:\n");
+			unstaged_header = true;
+		}
+
+		switch (delta->status) {
+		case GIT_DELTA_DELETED:
+			change_type = "deleted:";
+			file = delta->old_file.path;
+			break;
+		case GIT_DELTA_MODIFIED:
+			change_type = "modified:";
+			file = delta->old_file.path;
+			break;
+		default:
+			printf("%d\n", delta->status);
+			CLI_ASSERT(!"unhandled workdir->index delta type");
+			break;
+		}
+
+		git_str_printf(message, "#       %-11s %s", change_type, file);
+
+		if (delta->status == GIT_DELTA_RENAMED)
+			git_str_printf(message, " -> %s", delta->new_file.path);
+
+		git_str_printf(message, "\n");
+	}
+
+	for (i = 0; i < entries; i++) {
+		entry = git_status_byindex(status, i);
+
+		if (!(delta = entry->index_to_workdir) ||
+		    delta->status != GIT_DELTA_UNTRACKED)
+			continue;
+
+		if (!untracked_header) {
+			if (staged_header || unstaged_header)
+				git_str_puts(message, "#\n");
+
+			git_str_puts(message, "# Untracked files:\n");
+			untracked_header = true;
+		}
+
+		git_str_printf(message, "#       %s\n", delta->new_file.path);
+	}
+
+	if (git_str_oom(message))
+		return cli_error_git();
+
+	return 0;
+}
+
+static int prepare_initial_message(
+	git_str *message,
+	git_repository *repo,
+	git_status_list *status)
+{
+	git_reference *head_ref = NULL;
+	const char *branch_name = NULL;
+	int ret;
+
+	if (git_repository_head(&head_ref, repo) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if (git_branch_name(&branch_name, head_ref) < 0)
+		git_error_clear();
+
+	if (amend)
+		ret = prepare_amend_message(message, head_ref);
+	else
+		ret = prepare_template(message, repo);
+
+	if (ret < 0)
+		goto done;
+
+	git_str_puts(message, "\n" MESSAGE_INSTRUCTIONS "#\n");
+
+	if (branch_name)
+		git_str_printf(message, "# On branch %s\n", branch_name);
+	else
+		git_str_printf(message, "# Not currently on any branch.\n");
+
+	ret = prepare_changes(message, status);
+
+done:
+	git_reference_free(head_ref);
+	return ret;
+}
+
+static int should_sign(bool *out, git_repository *repo)
+{
+	git_config *config = NULL;
+	int sign, error, ret = 0;
+
+	if (no_sign) {
+		*out = false;
+		return 0;
+	}
+
+	if (keyid != unset_keyid) {
+		*out = true;
+		return 0;
+	}
+
+	if (git_repository_config(&config, repo) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	error = git_config_get_bool(&sign, config, "commit.gpgsign");
+
+	if (error == GIT_ENOTFOUND)
+		*out = false;
+	else
+		*out = !!sign;
+
+done:
+	git_config_free(config);
+	return ret;
+}
+
+static int lookup_editor(char **out, git_repository *repo)
+{
+	git_str env = GIT_STR_INIT;
+	git_str term = GIT_STR_INIT;
+	git_buf buf = GIT_BUF_INIT;
+	git_config *config = NULL;
+	bool is_dumb = true;
+	int ret = 0;
+
+	if (git__getenv(&env, "GIT_EDITOR") == 0) {
+		*out = git_str_detach(&env);
+		goto done;
+	}
+
+	if (git_repository_config(&config, repo) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if (git_config_get_string_buf(&buf, config, "core.editor") == 0) {
+		*out = git__strdup(buf.ptr);
+
+		if (*out == NULL)
+			ret = -1;
+
+		goto done;
+	}
+
+	if (git__getenv(&term, "TERM") == 0)
+		is_dumb = (git__strcmp(term.ptr, "dumb") == 0);
+
+	if ((!is_dumb && git__getenv(&env, "VISUAL") == 0) ||
+	    git__getenv(&env, "EDITOR") == 0) {
+		*out = git_str_detach(&env);
+		goto done;
+	}
+
+	if (is_dumb) {
+		ret = cli_error("no EDITOR is specified");
+	} else {
+		*out = git__strdup("vi");
+		ret = *out == NULL ? -1 : 0;
+	}
+
+done:
+	git_buf_dispose(&buf);
+	git_str_dispose(&term);
+	git_str_dispose(&env);
+	git_config_free(config);
+	return ret;
+}
+
+static int read_commit_message(
+	git_buf *out,
+	git_repository *repo,
+	git_status_list *status)
+{
+	git_process *process = NULL;
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+	char *editor = NULL;
+	git_str cmdline = GIT_STR_INIT;
+	git_str message_file = GIT_STR_INIT;
+	git_str initial = GIT_STR_INIT;
+	git_str message = GIT_STR_INIT;
+	int ret = 0;
+
+	if ((ret = prepare_initial_message(&initial, repo, status)) != 0)
+		return ret;
+
+	if (git_str_joinpath(&message_file,
+			git_repository_path(repo),
+			"COMMIT_EDITMSG") < 0 ||
+	    git_futils_writebuffer(&initial, message_file.ptr,
+			O_CREAT|O_TRUNC|O_WRONLY, 0666) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if ((ret = lookup_editor(&editor, repo)) != 0)
+		goto done;
+
+	if (git_str_printf(&cmdline, "%s \"%s\"",
+			editor, message_file.ptr) < 0 ||
+	    git_process_new_from_cmdline(&process, cmdline.ptr,
+			NULL, 0, NULL) < 0 ||
+	    git_process_start(process) < 0 ||
+	    git_process_wait(&result, process) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if (result.status != GIT_PROCESS_STATUS_NORMAL ||
+	    result.exitcode != 0) {
+		ret = cli_error("could not invoke '%s': exit code %d",
+			editor, result.exitcode);
+		ret = 1;
+		goto done;
+	}
+
+	if (git_futils_readbuffer(&message, message_file.ptr) < 0 ||
+	    git_message_prettify(out, message.ptr, 1, '#') < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	ret = 0;
+
+done:
+	git_process_free(process);
+	git_str_dispose(&message);
+	git_str_dispose(&cmdline);
+	git_str_dispose(&message_file);
+	git_str_dispose(&initial);
+	git__free(editor);
+	return ret;
+}
+
+static int sign_commit(
+	git_commitbuilder *builder,
+	git_repository *repo,
+	const char *commit_content,
+	void *payload)
+{
+	git_process *process = NULL;
+	git_config *config = NULL;
+	git_buf config_value = GIT_BUF_INIT;
+	git_str committer_ident = GIT_STR_INIT, cmdline = GIT_STR_INIT,
+		signature = GIT_STR_INIT;
+	const char *args[3] = { "gpg", "-bsau", NULL };
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+	git_process_options process_opts = GIT_PROCESS_OPTIONS_INIT;
+	git_signature *committer = NULL;
+	char buf[16];
+	ssize_t read_len;
+	int ret = 0;
+
+	GIT_UNUSED(builder);
+	GIT_UNUSED(commit_content);
+	GIT_UNUSED(payload);
+
+	if (git_repository_config(&config, repo) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if (git_config_get_string_buf(&config_value, config, "gpg.program") == 0)
+		args[0] = config_value.ptr;
+
+	if (keyid && keyid != unset_keyid) {
+		args[2] = keyid;
+	} else {
+		if (git_signature_default_from_env(NULL, &committer, repo) < 0 ||
+		    git_str_printf(&committer_ident, "%s <%s>", committer->name, committer->email) < 0) {
+			ret = cli_error_git();
+			goto done;
+		}
+
+		args[2] = committer_ident.ptr;
+	}
+
+	process_opts.capture_in = 1;
+	process_opts.capture_out = 1;
+
+	if (git_process_new(&process, args, 3, NULL, 0, &process_opts) < 0 ||
+	    git_process_start(process) < 0 ||
+	    git_process_write(process, commit_content, strlen(commit_content)) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	git_process_close_in(process);
+
+	while ((read_len = git_process_read(process, buf, sizeof(buf))) > 0) {
+		if (git_str_put(&signature, buf, (size_t)read_len) < 0) {
+			ret = cli_error_git();
+			goto done;
+		}
+	}
+
+	if (read_len < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if (git_process_wait(&result, process) < 0 ||
+	    git_commitbuilder_add_header(builder, "gpgsig", signature.ptr) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	ret = result.exitcode == 0 ? 0 : GIT_EUSER;
+
+done:
+	git_signature_free(committer);
+	git_buf_dispose(&config_value);
+	git_str_dispose(&cmdline);
+	git_str_dispose(&committer_ident);
+	git_str_dispose(&signature);
+	git_process_close(process);
+	git_process_free(process);
+
+	return ret;
+}
+
+int cmd_commit(int argc, char **argv)
+{
+	cli_repository_open_options open_opts = { argv + 1, argc - 1};
+	git_status_options status_opts = GIT_STATUS_OPTIONS_INIT;
+	git_commit_create_options commit_opts = GIT_COMMIT_CREATE_OPTIONS_INIT;
+	git_repository *repo = NULL;
+	git_index *index = NULL;
+	git_status_list *status = NULL;
+	git_tree *tree = NULL;
+	git_oid commit_id, tree_id;
+	git_buf read_message = GIT_BUF_INIT;
+	cli_opt invalid_opt;
+	bool sign = false;
+	int error, ret = 0;
+
+	if (cli_opt_parse(&invalid_opt, opts, argv + 1, argc - 1, CLI_OPT_PARSE_GNU))
+		return cli_opt_usage_error(COMMAND_NAME, opts, &invalid_opt);
+
+	status_opts.flags |= GIT_STATUS_OPT_RENAMES_HEAD_TO_INDEX;
+	status_opts.flags |= GIT_STATUS_OPT_INCLUDE_UNTRACKED;
+
+	/* We check for empty commits; don't duplicate the check. */
+	commit_opts.allow_empty_commit = true;
+	commit_opts.payload = repo;
+
+	if (cli_opt__show_help) {
+		print_help();
+		return 0;
+	}
+
+	if (cli_repository_open(&repo, &open_opts) < 0 ||
+	    git_repository_index(&index, repo) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if ((ret = should_sign(&sign, repo)) != 0)
+		goto done;
+
+	if (sign)
+		commit_opts.sign = sign_commit;
+
+	if (git_status_list_new(&status, repo, &status_opts) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if ((ret = check_empty_commit(status)) != 0)
+		goto done;
+
+	if (git_index_write_tree(&tree_id, index) < 0 ||
+	    git_tree_lookup(&tree, repo, &tree_id) < 0) {
+		ret = cli_error_git();
+		goto done;
+	}
+
+	if (!message) {
+		if ((ret = read_commit_message(&read_message,
+				repo, status)) != 0)
+			goto done;
+
+		message = read_message.ptr;
+	}
+
+	if (!*message && !allow_empty_message) {
+		ret = cli_error("no commit message specified (use \"--allow-empty-message\")");
+		goto done;
+	}
+
+	if (amend)
+		error = git_commit_amend_from_tree(&commit_id,
+			repo, tree, message, &commit_opts);
+	else
+		error = git_commit_create_from_tree(&commit_id,
+			repo, tree, message, &commit_opts);
+
+	if (error == GIT_EUSER)
+		ret = CLI_EXIT_GIT;
+	else if (error < 0)
+		ret = cli_error_git();
+
+done:
+	git_buf_dispose(&read_message);
+	git_status_list_free(status);
+	git_index_free(index);
+	git_repository_free(repo);
+	return ret;
+}
diff --git a/src/cli/error.h b/src/cli/error.h
index abf8a5160..90562477f 100644
--- a/src/cli/error.h
+++ b/src/cli/error.h
@@ -48,4 +48,17 @@ GIT_INLINE(int) cli_error_git(void)
 
 #define cli_error_os() (perror(PROGRAM_NAME), CLI_EXIT_OS)
 
+#if (defined(_DEBUG) || defined(GIT_ASSERT_HARD)) && GIT_ASSERT_HARD != 0
+# include <assert.h>
+# define CLI_ASSERT(expr) assert(expr)
+#else
+# define CLI_ASSERT(expr) do { \
+		if (!(expr)) { \
+			fprintf(stderr, "%s: assertion failed: '%s'\n", \
+				PROGRAM_NAME, #expr); \
+			exit(255); \
+		} \
+	} while(0)
+#endif
+
 #endif /* CLI_error_h__ */
diff --git a/src/cli/main.c b/src/cli/main.c
index 4716d6dde..8a74983b9 100644
--- a/src/cli/main.c
+++ b/src/cli/main.c
@@ -33,6 +33,7 @@ const cli_cmd_spec cli_cmds[] = {
 	{ "blame",       cmd_blame,       "Show the origin of each line of a file" },
 	{ "cat-file",    cmd_cat_file,    "Display an object in the repository" },
 	{ "clone",       cmd_clone,       "Clone a repository into a new directory" },
+	{ "commit",      cmd_commit,      "Commit the current contents of the index" },
 	{ "config",      cmd_config,      "View or set configuration values " },
 	{ "hash-object", cmd_hash_object, "Hash a raw object and product its object ID" },
 	{ "help",        cmd_help,        "Display help information" },
diff --git a/src/cli/opt.c b/src/cli/opt.c
index c5def1930..9b0a15869 100644
--- a/src/cli/opt.c
+++ b/src/cli/opt.c
@@ -270,7 +270,9 @@ static cli_opt_status_t parse_short(cli_opt *opt, cli_opt_parser *parser)
 	}
 
 	/* Required argument was not provided */
-	if (spec->type == CLI_OPT_TYPE_VALUE && !opt->value)
+	if (spec->type == CLI_OPT_TYPE_VALUE &&
+	    !opt->value &&
+	    !(spec->usage & CLI_OPT_USAGE_VALUE_OPTIONAL))
 		opt->status = CLI_OPT_STATUS_MISSING_VALUE;
 	else
 		opt->status = CLI_OPT_STATUS_OK;
diff --git a/src/cli/opt_usage.c b/src/cli/opt_usage.c
index 5b6aee921..304352898 100644
--- a/src/cli/opt_usage.c
+++ b/src/cli/opt_usage.c
@@ -14,7 +14,7 @@
 
 static int print_spec_args(git_str *out, const cli_opt_spec *spec)
 {
-	GIT_ASSERT(!is_switch_or_value(spec));
+	CLI_ASSERT(!is_switch_or_value(spec));
 
 	if (spec->type == CLI_OPT_TYPE_ARG)
 		return git_str_printf(out, "<%s>", spec->value_name);
@@ -23,13 +23,13 @@ static int print_spec_args(git_str *out, const cli_opt_spec *spec)
 	if (spec->type == CLI_OPT_TYPE_LITERAL)
 		return git_str_printf(out, "--");
 
-	GIT_ASSERT(!"unknown option spec type");
+	CLI_ASSERT(!"unknown option spec type");
 	return -1;
 }
 
 GIT_INLINE(int) print_spec_alias(git_str *out, const cli_opt_spec *spec)
 {
-	GIT_ASSERT(is_switch_or_value(spec) && spec->alias);
+	CLI_ASSERT(is_switch_or_value(spec) && spec->alias);
 
 	if (spec->type == CLI_OPT_TYPE_VALUE &&
 	    !(spec->usage & CLI_OPT_USAGE_VALUE_OPTIONAL))
@@ -42,7 +42,7 @@ GIT_INLINE(int) print_spec_alias(git_str *out, const cli_opt_spec *spec)
 
 GIT_INLINE(int) print_spec_name(git_str *out, const cli_opt_spec *spec)
 {
-	GIT_ASSERT(is_switch_or_value(spec) && spec->name);
+	CLI_ASSERT(is_switch_or_value(spec) && spec->name);
 
 	if (spec->type == CLI_OPT_TYPE_VALUE &&
 	    !(spec->usage & CLI_OPT_USAGE_VALUE_OPTIONAL))
diff --git a/src/cli/progress.c b/src/cli/progress.c
index d975b0954..a6a940df1 100644
--- a/src/cli/progress.c
+++ b/src/cli/progress.c
@@ -302,7 +302,7 @@ int cli_progress_fetch_transfer(const git_indexer_progress *stats, void *payload
 
 	default:
 		/* should not be reached */
-		GIT_ASSERT(!"unexpected progress state");
+		CLI_ASSERT(!"unexpected progress state");
 	}
 
 	return error;
@@ -337,7 +337,7 @@ int cli_progress_indexer(
 
 	default:
 		/* should not be reached */
-		GIT_ASSERT(!"unexpected progress state");
+		CLI_ASSERT(!"unexpected progress state");
 	}
 
 	return error;
diff --git a/src/util/unix/process.c b/src/util/unix/process.c
index 72308b1de..3d62ec6af 100644
--- a/src/util/unix/process.c
+++ b/src/util/unix/process.c
@@ -204,7 +204,9 @@ extern int git_process_new_from_cmdline(
 {
 	git_process_options merged_opts = {0};
 
-	memcpy(&merged_opts, opts, sizeof(git_process_options));
+	if (opts)
+		memcpy(&merged_opts, opts, sizeof(git_process_options));
+
 	merged_opts.use_shell = 1;
 
 	return git_process_new(out, &cmdline, 1, env, env_len, &merged_opts);