Re: [PATCH v2] rebase -x: sanity check command

> Range-diff against v1:
> 1:  9626549aec ! 1:  726b84c300 rebase -x: sanity check command
>     @@ -2,8 +2,9 @@
>      
>          rebase -x: sanity check command
>      
>     -    If the user gives an empty argument to --exec then the rebase starts to
>     -    run before erroring out with
>     +    If the user gives an empty argument to --exec then git creates a todo
>     +    list that it cannot parse. The rebase starts to run before erroring out
>     +    with
>      
>            error: missing arguments for exec
>            error: invalid line 2: exec
>     @@ -33,21 +34,16 @@
>       
>      +static int check_exec_cmd(const char *cmd)
>      +{
>     -+	int non_blank = 0;
>     ++	if (strchr(cmd, '\n'))
>     ++		return error(_("exec commands cannot contain newlines"));
>      +
>     -+	while (*cmd) {
>     -+		if (*cmd == '\n')
>     -+			return error(_("exec commands cannot contain newlines"));
>     -+		if (!isspace(*cmd))
>     -+			non_blank = 1;
>     -+		cmd++;
>     -+	}
>     ++	/* Does the command consist purely of whitespace? */
>     ++	if (!cmd[strspn(cmd, " \t\r\f\v")])
>     ++		return error(_("empty exec command"));
>      +
>     -+	if (non_blank)
>     -+		return 0;
>     -+
>     -+	return error(_("empty exec command"));
>     ++	return 0;
>      +}
>     ++
>      +
>       int cmd_rebase(int argc, const char **argv, const char *prefix)
>       {