Commit e5618106 authored by Vikrant Varma's avatar Vikrant Varma Committed by Junio C Hamano

help: add help_unknown_ref()

When the user gives an unknown string to a command that expects to
get a ref, we could be more helpful than just saying "that's not a
ref" and die.

Add helper function help_unknown_ref() to take care of displaying an
error message along with a list of suggested refs the user might
have meant.  An interaction with "git merge" might go like this:

	$ git merge foo
	merge: foo - not something we can merge

	Did you mean one of these?
Signed-off-by: default avatarVikrant Varma <[email protected]>
Signed-off-by: default avatarJunio C Hamano <[email protected]>
parent 9b795193
......@@ -7,6 +7,7 @@
#include "string-list.h"
#include "column.h"
#include "version.h"
#include "refs.h"
void add_cmdname(struct cmdnames *cmds, const char *name, int len)
......@@ -404,3 +405,52 @@ int cmd_version(int argc, const char **argv, const char *prefix)
printf("git version %s\n", git_version_string);
return 0;
struct similar_ref_cb {
const char *base_ref;
struct string_list *similar_refs;
static int append_similar_ref(const char *refname, const unsigned char *sha1,
int flags, void *cb_data)
struct similar_ref_cb *cb = (struct similar_ref_cb *)(cb_data);
char *branch = strrchr(refname, '/') + 1;
/* A remote branch of the same name is deemed similar */
if (!prefixcmp(refname, "refs/remotes/") &&
!strcmp(branch, cb->base_ref))
refname + strlen("refs/remotes/"));
return 0;
static struct string_list guess_refs(const char *ref)
struct similar_ref_cb ref_cb;
struct string_list similar_refs = STRING_LIST_INIT_NODUP;
ref_cb.base_ref = ref;
ref_cb.similar_refs = &similar_refs;
for_each_ref(append_similar_ref, &ref_cb);
return similar_refs;
void help_unknown_ref(const char *ref, const char *cmd, const char *error)
int i;
struct string_list suggested_refs = guess_refs(ref);
fprintf_ln(stderr, _("%s: %s - %s"), cmd, ref, error);
if ( > 0) {
Q_("\nDid you mean this?",
"\nDid you mean one of these?",;
for (i = 0; i <; i++)
fprintf(stderr, "\t%s\n", suggested_refs.items[i].string);
string_list_clear(&suggested_refs, 0);
......@@ -27,4 +27,9 @@ extern void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes);
extern int is_in_cmdlist(struct cmdnames *cmds, const char *name);
extern void list_commands(unsigned int colopts, struct cmdnames *main_cmds, struct cmdnames *other_cmds);
* call this to die(), when it is suspected that the user mistyped a
* ref to the command, to give suggested "correct" refs.
extern void help_unknown_ref(const char *ref, const char *cmd, const char *error);
#endif /* HELP_H */
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