This patch introduces a modified Damerau-Levenshtein algorithm into
Git's code base, and uses it with the following penalties to show some
similar commands when an unknown command was encountered:
swap = 0, insertion = 1, substitution = 2, deletion = 4
A typical output would now look like this:
$ git sm
git: 'sm' is not a git-command. See 'git --help'.
Did you mean one of these?
am
rm
The cut-off is at similarity rating 6, which was empirically determined
to give sensible results.
As a convenience, if there is only one candidate, Git continues under
the assumption that the user mistyped it. Example:
$ git reabse
WARNING: You called a Git program named 'reabse', which does
not exist.
Continuing under the assumption that you meant 'rebase'
[...]
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
So I mistyped 'reabse' for the hundred trillionth time, but I
will never have to correct my mistakes again.
Note: this patch is _not_ meant for inclusion.
Makefile | 2 +
builtin.h | 2 +-
git.c | 4 ++-
help.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
levenshtein.c | 47 +++++++++++++++++++++++++++++++++++++++++++
levenshtein.h | 8 +++++++
6 files changed, 121 insertions(+), 3 deletions(-)
create mode 100644 levenshtein.c
create mode 100644 levenshtein.h
diff --git a/Makefile b/Makefile
index 19bdd03..7e114e0 100644
--- a/Makefile
+++ b/Makefile
@@ -347,6 +347,7 @@ LIB_H += git-compat-util.h
LIB_H += graph.h
LIB_H += grep.h
LIB_H += hash.h
+LIB_H += levenshtein.h
LIB_H += list-objects.h
LIB_H += ll-merge.h
LIB_H += log-tree.h
@@ -421,6 +422,7 @@ LIB_OBJS += hash.o
LIB_OBJS += help.o
LIB_OBJS += ident.o
LIB_OBJS += interpolate.o
+LIB_OBJS += levenshtein.o
LIB_OBJS += list-objects.o
LIB_OBJS += ll-merge.o
LIB_OBJS += lockfile.o
diff --git a/builtin.h b/builtin.h
index 0e605d4..fc5f108 100644
--- a/builtin.h
+++ b/builtin.h
@@ -11,7 +11,7 @@ extern const char git_usage_string[];
extern const char git_more_info_string[];
extern void list_common_cmds_help(void);
-extern void help_unknown_cmd(const char *cmd);
+extern const char *help_unknown_cmd(const char *cmd);
extern void prune_packed_objects(int);
extern int read_line_with_nul(char *buf, int size, FILE *file);
extern int fmt_merge_msg(int merge_summary, struct strbuf *in,
diff --git a/git.c b/git.c
index 1bfd271..d7510ef 100644
--- a/git.c
+++ b/git.c
@@ -500,7 +500,9 @@ int main(int argc, const char **argv)
cmd, argv[0]);
exit(1);
}
- help_unknown_cmd(cmd);
+ argv[0] = help_unknown_cmd(cmd);
+ handle_internal_command(argc, argv);
+ execv_dashed_external(argv);
}
fprintf(stderr, "Failed to run command '%s': %s\n",
diff --git a/help.c b/help.c
index bfc84ae..480befe 100644
--- a/help.c
+++ b/help.c
@@ -9,6 +9,7 @@
#include "common-cmds.h"
#include "parse-options.h"
#include "run-command.h"
+#include "levenshtein.h"
static struct man_viewer_list {
struct man_viewer_list *next;
@@ -666,9 +667,67 @@ static void show_html_page(const char *git_cmd)
open_html(page_path.buf);
}
-void help_unknown_cmd(const char *cmd)
+static const char *levenshtein_cmd;
+static int similarity(const char *cmd) {
+ return levenshtein(levenshtein_cmd, cmd, 0, 2, 1, 4);
+}
+
+static int levenshtein_compare(const void *p1, const void *p2)
+{
+ const struct cmdname *const *c1 = p1, *const *c2 = p2;
+ const char *s1 = (*c1)->name, *s2 = (*c2)->name;
+ int l1 = similarity(s1);
+ int l2 = similarity(s2);
+ return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
+}
+
+const char *help_unknown_cmd(const char *cmd)
{
+ int i, best_similarity = 0;
+ char cwd[PATH_MAX];
+
+ if (!getcwd(cwd, sizeof(cwd))) {
+ error("Could not get current working directory");
+ cwd[0] = '\0';
+ }
+
+ load_command_list();
+ ALLOC_GROW(main_cmds.names, main_cmds.cnt + other_cmds.cnt,
+ main_cmds.alloc);
+ memcpy(main_cmds.names + main_cmds.cnt, other_cmds.names,
+ other_cmds.cnt * sizeof(other_cmds.names[0]));
+ main_cmds.cnt += other_cmds.cnt;
+
+ levenshtein_cmd = cmd;
+ qsort(main_cmds.names, main_cmds.cnt,
+ sizeof(*main_cmds.names), levenshtein_compare);
+
+ if (!main_cmds.cnt)
+ die ("Uh oh. Your system reports no Git commands at all.");
+ best_similarity = similarity(main_cmds.names[0]->name);
+ if (main_cmds.cnt < 2 || best_similarity <
+ similarity(main_cmds.names[1]->name)) {
+ if (!*cwd)
+ exit(1);
+ if (chdir(cwd))
+ die ("Could not change directory back to '%s'", cwd);
+ fprintf(stderr, "WARNING: You called a Git program named '%s', "
+ "which does not exist.\n"
+ "Continuing under the assumption that you meant '%s'\n",
+ cmd, main_cmds.names[0]->name);
+ return main_cmds.names[0]->name;
+ }
+
fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
+
+ if (best_similarity < 6) {
+ fprintf(stderr, "\nDid you mean one of these?\n");
+
+ for (i = 0; i < main_cmds.cnt && best_similarity ==
+ similarity(main_cmds.names[i]->name); i++)
+ fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
+ }
+
exit(1);
}
diff --git a/levenshtein.c b/levenshtein.c
new file mode 100644
index 0000000..db52f2c
--- /dev/null
+++ b/levenshtein.c
@@ -0,0 +1,47 @@
+#include "cache.h"
+#include "levenshtein.h"
+
+int levenshtein(const char *string1, const char *string2,
+ int w, int s, int a, int d)
+{
+ int len1 = strlen(string1), len2 = strlen(string2);
+ int *row0 = xmalloc(sizeof(int) * (len2 + 1));
+ int *row1 = xmalloc(sizeof(int) * (len2 + 1));
+ int *row2 = xmalloc(sizeof(int) * (len2 + 1));
+ int i, j;
+
+ for (j = 0; j <= len2; j++)
+ row1[j] = j * a;
+ for (i = 0; i < len1; i++) {
+ int *dummy;
+
+ row2[0] = (i + 1) * d;
+ for (j = 0; j < len2; j++) {
+ /* substitution */
+ row2[j + 1] = row1[j] + s * (string1[i] != string2[j]);
+ /* swap */
+ if (i > 0 && j > 0 && string1[i - 1] == string2[j] &&
+ string1[i] == string2[j - 1] &&
+ row2[j + 1] > row0[j - 1] + w)
+ row2[j + 1] = row0[j - 1] + w;
+ /* deletion */
+ if (j + 1 < len2 && row2[j + 1] > row1[j + 1] + d)
+ row2[j + 1] = row1[j + 1] + d;
+ /* insertion */
+ if (row2[j + 1] > row2[j] + a)
+ row2[j + 1] = row2[j] + a;
+ }
+
+ dummy = row0;
+ row0 = row1;
+ row1 = row2;
+ row2 = dummy;
+ }
+
+ i = row1[len2];
+ free(row0);
+ free(row1);
+ free(row2);
+
+ return i;
+}
diff --git a/levenshtein.h b/levenshtein.h
new file mode 100644
index 0000000..0173abe
--- /dev/null
+++ b/levenshtein.h
@@ -0,0 +1,8 @@
+#ifndef LEVENSHTEIN_H
+#define LEVENSHTEIN_H
+
+int levenshtein(const char *string1, const char *string2,
+ int swap_penalty, int substition_penalty,
+ int insertion_penalty, int deletion_penalty);
+
+#endif
--
1.6.0.rc0.21.g91175
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
