static int default_email_is_bogus;
 static int default_name_is_bogus;
 
+static int ident_use_config_only;
+
 #define IDENT_NAME_GIVEN 01
 #define IDENT_MAIL_GIVEN 02
 #define IDENT_ALL_GIVEN (IDENT_NAME_GIVEN|IDENT_MAIL_GIVEN)
 static int committer_ident_explicitly_given;
 static int author_ident_explicitly_given;
+static int ident_config_given;
 
 #ifdef NO_GECOS_IN_PWENT
 #define get_gecos(ignored) "&"
        mailname = fopen("/etc/mailname", "r");
        if (!mailname) {
                if (errno != ENOENT)
-                       warning("cannot open /etc/mailname: %s",
-                               strerror(errno));
+                       warning_errno("cannot open /etc/mailname");
                return -1;
        }
-       if (strbuf_getline(&mailnamebuf, mailname, '\n') == EOF) {
+       if (strbuf_getline(&mailnamebuf, mailname) == EOF) {
                if (ferror(mailname))
-                       warning("cannot read /etc/mailname: %s",
-                               strerror(errno));
+                       warning_errno("cannot read /etc/mailname");
                strbuf_release(&mailnamebuf);
                fclose(mailname);
                return -1;
        char buf[1024];
 
        if (gethostname(buf, sizeof(buf))) {
-               warning("cannot get host name: %s", strerror(errno));
+               warning_errno("cannot get host name");
                strbuf_addstr(out, "(none)");
                *is_bogus = 1;
                return;
        int want_date = !(flag & IDENT_NO_DATE);
        int want_name = !(flag & IDENT_NO_NAME);
 
-       if (want_name && !name)
-               name = ident_default_name();
-       if (!email)
-               email = ident_default_email();
-
-       if (want_name && !*name) {
-               struct passwd *pw;
-
-               if (strict) {
-                       if (name == git_default_name.buf)
+       if (want_name) {
+               int using_default = 0;
+               if (!name) {
+                       if (strict && ident_use_config_only
+                           && !(ident_config_given & IDENT_NAME_GIVEN)) {
+                               fputs(env_hint, stderr);
+                               die("no name was given and auto-detection is disabled");
+                       }
+                       name = ident_default_name();
+                       using_default = 1;
+                       if (strict && default_name_is_bogus) {
                                fputs(env_hint, stderr);
-                       die("empty ident name (for <%s>) not allowed", email);
+                               die("unable to auto-detect name (got '%s')", name);
+                       }
+               }
+               if (!*name) {
+                       struct passwd *pw;
+                       if (strict) {
+                               if (using_default)
+                                       fputs(env_hint, stderr);
+                               die("empty ident name (for <%s>) not allowed", email);
+                       }
+                       pw = xgetpwuid_self(NULL);
+                       name = pw->pw_name;
                }
-               pw = xgetpwuid_self(NULL);
-               name = pw->pw_name;
-       }
-
-       if (want_name && strict &&
-           name == git_default_name.buf && default_name_is_bogus) {
-               fputs(env_hint, stderr);
-               die("unable to auto-detect name (got '%s')", name);
        }
 
-       if (strict && email == git_default_email.buf && default_email_is_bogus) {
-               fputs(env_hint, stderr);
-               die("unable to auto-detect email address (got '%s')", email);
+       if (!email) {
+               if (strict && ident_use_config_only
+                   && !(ident_config_given & IDENT_MAIL_GIVEN)) {
+                       fputs(env_hint, stderr);
+                       die("no email was given and auto-detection is disabled");
+               }
+               email = ident_default_email();
+               if (strict && default_email_is_bogus) {
+                       fputs(env_hint, stderr);
+                       die("unable to auto-detect email address (got '%s')", email);
+               }
        }
 
        strbuf_reset(&ident);
 
 int git_ident_config(const char *var, const char *value, void *data)
 {
+       if (!strcmp(var, "user.useconfigonly")) {
+               ident_use_config_only = git_config_bool(var, value);
+               return 0;
+       }
+
        if (!strcmp(var, "user.name")) {
                if (!value)
                        return config_error_nonbool(var);
                strbuf_addstr(&git_default_name, value);
                committer_ident_explicitly_given |= IDENT_NAME_GIVEN;
                author_ident_explicitly_given |= IDENT_NAME_GIVEN;
+               ident_config_given |= IDENT_NAME_GIVEN;
                return 0;
        }
 
                strbuf_addstr(&git_default_email, value);
                committer_ident_explicitly_given |= IDENT_MAIL_GIVEN;
                author_ident_explicitly_given |= IDENT_MAIL_GIVEN;
+               ident_config_given |= IDENT_MAIL_GIVEN;
                return 0;
        }