git-grep: use a bit more specific error messages.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/builtin-grep.c b/builtin-grep.c
index bc53546dc713f425e1d35fd3716265a0bdf01702..6973c66704326804def00a22bfdcdb487dcad4c2 100644 (file)
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -657,6 +657,13 @@ static int grep_object(struct grep_opt *opt, const char **paths,
 static const char builtin_grep_usage[] =
 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
 
+static const char emsg_invalid_context_len[] =
+"%s: invalid context length argument";
+static const char emsg_missing_context_len[] =
+"missing context length argument";
+static const char emsg_missing_argument[] =
+"option requires an argument -%s";
+
 int cmd_grep(int argc, const char **argv, char **envp)
 {
        int hit = 0;
@@ -764,7 +771,7 @@ int cmd_grep(int argc, const char **argv, char **envp)
                        case 'A': case 'B': case 'C':
                                if (!arg[2]) {
                                        if (argc <= 1)
-                                               usage(builtin_grep_usage);
+                                               die(emsg_missing_context_len);
                                        scan = *++argv;
                                        argc--;
                                }
@@ -776,7 +783,7 @@ int cmd_grep(int argc, const char **argv, char **envp)
                                break;
                        }
                        if (sscanf(scan, "%u", &num) != 1)
-                               usage(builtin_grep_usage);
+                               die(emsg_invalid_context_len, scan);
                        switch (arg[1]) {
                        case 'A':
                                opt.post_context = num;
@@ -795,7 +802,7 @@ int cmd_grep(int argc, const char **argv, char **envp)
                        int lno = 0;
                        char buf[1024];
                        if (argc <= 1)
-                               usage(builtin_grep_usage);
+                               die(emsg_missing_argument, arg);
                        patterns = fopen(argv[1], "r");
                        if (!patterns)
                                die("'%s': %s", argv[1], strerror(errno));
@@ -820,7 +827,7 @@ int cmd_grep(int argc, const char **argv, char **envp)
                                argc--;
                                continue;
                        }
-                       usage(builtin_grep_usage);
+                       die(emsg_missing_argument, arg);
                }
                if (!strcmp("--", arg)) {
                        /* later processing wants to have this at argv[1] */