Reduce cost of deletion in levenstein distance (4 -> 3)

moy · gitster · commit c41494f8c89c · 2012-05-29T11:12:59.000-07:00
Before this patch, a character deletion has the same cost as 2 swaps, or
4 additions, so Git prefers suggesting a completely scrambled command
name to removing a character. For example, "git tags" suggests "stage",
but not "tag".

By setting the deletion cost to 3, we keep it higher than swaps or
additions, but prefer 1 deletion to 2 swaps. "git tags" now suggests
"tag" in addition to staged.

Signed-off-by: Matthieu Moy &lt;Matthieu.Moy@imag.fr&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/help.c b/help.c
@@ -317,7 +317,7 @@ const char *help_unknown_cmd(const char *cmd)
 		}
 
 		main_cmds.names[i]->len =
-			levenshtein(cmd, candidate, 0, 2, 1, 4) + 1;
+			levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;
 	}
 
 	qsort(main_cmds.names, main_cmds.cnt,

Original file line number	Diff line number	Diff line change
`@@ -317,7 +317,7 @@ const char help_unknown_cmd(const char cmd)`
`317`	`317`	`}`
`318`	`318`
`319`	`319`	`main_cmds.names[i]->len =`
`320`		`- levenshtein(cmd, candidate, 0, 2, 1, 4) + 1;`
	`320`	`+ levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;`
`321`	`321`	`}`
`322`	`322`
`323`	`323`	`qsort(main_cmds.names, main_cmds.cnt,`