1 files changed, 83 insertions, 50 deletions

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 03eff73fd0..2e8b0d18f4 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1,7 +1,6 @@
 #define USE_THE_INDEX_VARIABLE
 #include "builtin.h"
 #include "advice.h"
-#include "blob.h"
 #include "branch.h"
 #include "cache-tree.h"
 #include "checkout.h"
@@ -27,10 +26,8 @@
 #include "remote.h"
 #include "resolve-undo.h"
 #include "revision.h"
-#include "run-command.h"
 #include "setup.h"
 #include "submodule.h"
-#include "submodule-config.h"
 #include "symlinks.h"
 #include "trace2.h"
 #include "tree.h"
@@ -523,6 +520,15 @@ static int checkout_paths(const struct checkout_opts *opts,
 			    "--merge", "--conflict", "--staged");
 	}
 
+	/*
+	 * recreating unmerged index entries and writing out data from
+	 * unmerged index entries would make no sense when checking out
+	 * of a tree-ish.
+	 */
+	if ((opts->merge || opts->writeout_stage) && opts->source_tree)
+		die(_("'%s', '%s', or '%s' cannot be used when checking out of a tree"),
+		    "--merge", "--ours", "--theirs");
+
 	if (opts->patch_mode) {
 		enum add_p_mode patch_mode;
 		const char *rev = new_branch_info->name;
@@ -560,6 +566,8 @@ static int checkout_paths(const struct checkout_opts *opts,
 
 	if (opts->source_tree)
 		read_tree_some(opts->source_tree, &opts->pathspec);
+	if (opts->merge)
+		unmerge_index(&the_index, &opts->pathspec, CE_MATCHED);
 
 	ps_matched = xcalloc(opts->pathspec.nr, 1);
 
@@ -583,10 +591,6 @@ static int checkout_paths(const struct checkout_opts *opts,
 	}
 	free(ps_matched);
 
-	/* "checkout -m path" to recreate conflicted state */
-	if (opts->merge)
-		unmerge_marked_index(&the_index);
-
 	/* Any unmerged paths? */
 	for (pos = 0; pos < the_index.cache_nr; pos++) {
 		const struct cache_entry *ce = the_index.cache[pos];
@@ -700,7 +704,8 @@ static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 	init_checkout_metadata(&opts.meta, info->refname,
 			       info->commit ? &info->commit->object.oid : null_oid(),
 			       NULL);
-	parse_tree(tree);
+	if (parse_tree(tree) < 0)
+		return 128;
 	init_tree_desc(&tree_desc, &tree->object.oid, tree->buffer, tree->size);
 	switch (unpack_trees(1, &tree_desc, &opts)) {
 	case -2:
@@ -779,9 +784,15 @@ static int merge_working_tree(const struct checkout_opts *opts,
 		if (new_branch_info->commit)
 			BUG("'switch --orphan' should never accept a commit as starting point");
 		new_tree = parse_tree_indirect(the_hash_algo->empty_tree);
-	} else
+		if (!new_tree)
+			BUG("unable to read empty tree");
+	} else {
 		new_tree = repo_get_commit_tree(the_repository,
 						new_branch_info->commit);
+		if (!new_tree)
+			return error(_("unable to read tree (%s)"),
+				     oid_to_hex(&new_branch_info->commit->object.oid));
+	}
 	if (opts->discard_changes) {
 		ret = reset_tree(new_tree, opts, 1, writeout_error, new_branch_info);
 		if (ret)
@@ -817,7 +828,8 @@ static int merge_working_tree(const struct checkout_opts *opts,
 
 		init_tree_desc(&trees[0], &tree->object.oid,
 			       tree->buffer, tree->size);
-		parse_tree(new_tree);
+		if (parse_tree(new_tree) < 0)
+			exit(128);
 		tree = new_tree;
 		init_tree_desc(&trees[1], &tree->object.oid,
 			       tree->buffer, tree->size);
@@ -1197,6 +1209,8 @@ static int git_checkout_config(const char *var, const char *value,
 	struct checkout_opts *opts = cb;
 
 	if (!strcmp(var, "diff.ignoresubmodules")) {
+		if (!value)
+			return config_error_nonbool(var);
 		handle_ignore_submodules_arg(&opts->diff_options, value);
 		return 0;
 	}
@@ -1220,7 +1234,9 @@ static void setup_new_branch_info_and_source_tree(
 	struct tree **source_tree = &opts->source_tree;
 	struct object_id branch_rev;
 
-	new_branch_info->name = xstrdup(arg);
+	/* treat '@' as a shortcut for 'HEAD' */
+	new_branch_info->name = !strcmp(arg, "@") ? xstrdup("HEAD") :
+						    xstrdup(arg);
 	setup_branch_path(new_branch_info);
 
 	if (!check_refname_format(new_branch_info->path, 0) &&
@@ -1234,10 +1250,15 @@ static void setup_new_branch_info_and_source_tree(
 	if (!new_branch_info->commit) {
 		/* not a commit */
 		*source_tree = parse_tree_indirect(rev);
+		if (!*source_tree)
+			die(_("unable to read tree (%s)"), oid_to_hex(rev));
 	} else {
 		parse_commit_or_die(new_branch_info->commit);
 		*source_tree = repo_get_commit_tree(the_repository,
 						    new_branch_info->commit);
+		if (!*source_tree)
+			die(_("unable to read tree (%s)"),
+			    oid_to_hex(&new_branch_info->commit->object.oid));
 	}
 }
 
@@ -1511,6 +1532,26 @@ static void die_if_some_operation_in_progress(void)
 	wt_status_state_free_buffers(&state);
 }
 
+/*
+ * die if attempting to checkout an existing branch that is in use
+ * in another worktree, unless ignore-other-wortrees option is given.
+ * The check is bypassed when the branch is already the current one,
+ * as it will not make things any worse.
+ */
+static void die_if_switching_to_a_branch_in_use(struct checkout_opts *opts,
+						const char *full_ref)
+{
+	int flags;
+	char *head_ref;
+
+	if (opts->ignore_other_worktrees)
+		return;
+	head_ref = resolve_refdup("HEAD", 0, NULL, &flags);
+	if (head_ref && (!(flags & REF_ISSYMREF) || strcmp(head_ref, full_ref)))
+		die_if_checked_out(full_ref, 1);
+	free(head_ref);
+}
+
 static int checkout_branch(struct checkout_opts *opts,
 			   struct branch_info *new_branch_info)
 {
@@ -1571,14 +1612,15 @@ static int checkout_branch(struct checkout_opts *opts,
 	if (!opts->can_switch_when_in_progress)
 		die_if_some_operation_in_progress();
 
-	if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
-	    !opts->ignore_other_worktrees) {
-		int flag;
-		char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
-		if (head_ref &&
-		    (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path)))
-			die_if_checked_out(new_branch_info->path, 1);
-		free(head_ref);
+	/* "git checkout <branch>" */
+	if (new_branch_info->path && !opts->force_detach && !opts->new_branch)
+		die_if_switching_to_a_branch_in_use(opts, new_branch_info->path);
+
+	/* "git checkout -B <branch>" */
+	if (opts->new_branch_force) {
+		char *full_ref = xstrfmt("refs/heads/%s", opts->new_branch);
+		die_if_switching_to_a_branch_in_use(opts, full_ref);
+		free(full_ref);
 	}
 
 	if (!new_branch_info->commit && opts->new_branch) {
@@ -1622,7 +1664,7 @@ static struct option *add_common_switch_branch_options(
 			parse_opt_tracking_mode),
 		OPT__FORCE(&opts->force, N_("force checkout (throw away local modifications)"),
 			   PARSE_OPT_NOCOMPLETE),
-		OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
+		OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unborn branch")),
 		OPT_BOOL_F(0, "overwrite-ignore", &opts->overwrite_ignore,
 			   N_("update ignored files (default)"),
 			   PARSE_OPT_NOCOMPLETE),
@@ -1662,10 +1704,11 @@ static char cb_option = 'b';
 
 static int checkout_main(int argc, const char **argv, const char *prefix,
 			 struct checkout_opts *opts, struct option *options,
-			 const char * const usagestr[],
-			 struct branch_info *new_branch_info)
+			 const char * const usagestr[])
 {
 	int parseopt_flags = 0;
+	struct branch_info new_branch_info = { 0 };
+	int ret;
 
 	opts->overwrite_ignore = 1;
 	opts->prefix = prefix;
@@ -1781,7 +1824,7 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 			opts->track == BRANCH_TRACK_UNSPECIFIED &&
 			!opts->new_branch;
 		int n = parse_branchname_arg(argc, argv, dwim_ok,
-					     new_branch_info, opts, &rev);
+					     &new_branch_info, opts, &rev);
 		argv += n;
 		argc -= n;
 	} else if (!opts->accept_ref && opts->from_treeish) {
@@ -1790,7 +1833,7 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 		if (repo_get_oid_mb(the_repository, opts->from_treeish, &rev))
 			die(_("could not resolve %s"), opts->from_treeish);
 
-		setup_new_branch_info_and_source_tree(new_branch_info,
+		setup_new_branch_info_and_source_tree(&new_branch_info,
 						      opts, &rev,
 						      opts->from_treeish);
 
@@ -1810,7 +1853,7 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 		 * Try to give more helpful suggestion.
 		 * new_branch && argc > 1 will be caught later.
 		 */
-		if (opts->new_branch && argc == 1 && !new_branch_info->commit)
+		if (opts->new_branch && argc == 1 && !new_branch_info.commit)
 			die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
 				argv[0], opts->new_branch);
 
@@ -1860,9 +1903,16 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 	}
 
 	if (opts->patch_mode || opts->pathspec.nr)
-		return checkout_paths(opts, new_branch_info);
+		ret = checkout_paths(opts, &new_branch_info);
 	else
-		return checkout_branch(opts, new_branch_info);
+		ret = checkout_branch(opts, &new_branch_info);
+
+	branch_info_release(&new_branch_info);
+	clear_pathspec(&opts->pathspec);
+	free(opts->pathspec_from_file);
+	free(options);
+
+	return ret;
 }
 
 int cmd_checkout(int argc, const char **argv, const char *prefix)
@@ -1880,8 +1930,6 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode (default)")),
 		OPT_END()
 	};
-	int ret;
-	struct branch_info new_branch_info = { 0 };
 
 	memset(&opts, 0, sizeof(opts));
 	opts.dwim_new_local_branch = 1;
@@ -1911,13 +1959,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 	options = add_common_switch_branch_options(&opts, options);
 	options = add_checkout_path_options(&opts, options);
 
-	ret = checkout_main(argc, argv, prefix, &opts,
-			    options, checkout_usage, &new_branch_info);
-	branch_info_release(&new_branch_info);
-	clear_pathspec(&opts.pathspec);
-	free(opts.pathspec_from_file);
-	FREE_AND_NULL(options);
-	return ret;
+	return checkout_main(argc, argv, prefix, &opts, options,
+			     checkout_usage);
 }
 
 int cmd_switch(int argc, const char **argv, const char *prefix)
@@ -1935,8 +1978,6 @@ int cmd_switch(int argc, const char **argv, const char *prefix)
 			 N_("throw away local modifications")),
 		OPT_END()
 	};
-	int ret;
-	struct branch_info new_branch_info = { 0 };
 
 	memset(&opts, 0, sizeof(opts));
 	opts.dwim_new_local_branch = 1;
@@ -1955,11 +1996,8 @@ int cmd_switch(int argc, const char **argv, const char *prefix)
 
 	cb_option = 'c';
 
-	ret = checkout_main(argc, argv, prefix, &opts,
-			    options, switch_branch_usage, &new_branch_info);
-	branch_info_release(&new_branch_info);
-	FREE_AND_NULL(options);
-	return ret;
+	return checkout_main(argc, argv, prefix, &opts, options,
+			     switch_branch_usage);
 }
 
 int cmd_restore(int argc, const char **argv, const char *prefix)
@@ -1978,8 +2016,6 @@ int cmd_restore(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode")),
 		OPT_END()
 	};
-	int ret;
-	struct branch_info new_branch_info = { 0 };
 
 	memset(&opts, 0, sizeof(opts));
 	opts.accept_ref = 0;
@@ -1994,9 +2030,6 @@ int cmd_restore(int argc, const char **argv, const char *prefix)
 	options = add_common_options(&opts, options);
 	options = add_checkout_path_options(&opts, options);
 
-	ret = checkout_main(argc, argv, prefix, &opts,
-			    options, restore_usage, &new_branch_info);
-	branch_info_release(&new_branch_info);
-	FREE_AND_NULL(options);
-	return ret;
+	return checkout_main(argc, argv, prefix, &opts, options,
+			     restore_usage);
 }