env: remove vars that are not in default env

current env_set_default_vars() doesn't delete
var that are not in the imported env. hashtable
removes vars that are not in the imported
env but present in the current env only if H_NOCLEAR
flag is not set.

This change is to avoid passing H_NOCLEAR flag if
specific vars are passed to env_set_default_vars()

Without this change:
Marvell>> env default boot_mode
Marvell>>

With the change:
Marvell>> env default boot_mode
WARNING: 'boot_mode' not in imported env, deleting it!

Signed-off-by: Ravi Minnikanti <rminnikanti@marvell.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/usage/cmd/env.rst b/doc/usage/cmd/env.rst
index 9629f97..b65d85b 100644
--- a/doc/usage/cmd/env.rst
+++ b/doc/usage/cmd/env.rst
@@ -79,7 +79,8 @@
 environment to their default values.
 
     var
-        list of variable name.
+        list of variable names. If variable is not part of default
+        environment, it is deleted with a warning message on console.
     \-a
         all U-Boot environment.
     \-f
@@ -309,6 +310,7 @@
 Reset environment variable to default value, in memory::
 
     => env default bootcmd
+    => env default ipaddr serverip
     => env default -a
 
 Save current environment in persistent storage::
diff --git a/env/common.c b/env/common.c
index 8d47d72..6cba7f1 100644
--- a/env/common.c
+++ b/env/common.c
@@ -401,7 +401,15 @@
 	 * Special use-case: import from default environment
 	 * (and use \0 as a separator)
 	 */
-	flags |= H_NOCLEAR | H_DEFAULT;
+
+	/*
+	 * When vars are passed remove variables that are not in
+	 * the default environment.
+	 */
+	if (!nvars)
+		flags |= H_NOCLEAR;
+
+	flags |= H_DEFAULT;
 	return himport_r(&env_htab, default_environment,
 				sizeof(default_environment), '\0',
 				flags, 0, nvars, vars);
diff --git a/test/env/cmd_ut_env.c b/test/env/cmd_ut_env.c
index 13e0998..238cf31 100644
--- a/test/env/cmd_ut_env.c
+++ b/test/env/cmd_ut_env.c
@@ -9,6 +9,33 @@
 #include <test/suites.h>
 #include <test/ut.h>
 
+static int env_test_env_cmd(struct unit_test_state *uts)
+{
+	ut_assertok(run_command("setenv non_default_var1 1", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("setenv non_default_var2 1", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("env print non_default_var1", 0));
+	ut_assert_nextline("non_default_var1=1");
+	ut_assert_console_end();
+
+	ut_assertok(run_command("env default non_default_var1 non_default_var2", 0));
+	ut_assert_nextline("WARNING: 'non_default_var1' not in imported env, deleting it!");
+	ut_assert_nextline("WARNING: 'non_default_var2' not in imported env, deleting it!");
+	ut_assert_console_end();
+
+	ut_asserteq(1, run_command("env exists non_default_var1", 0));
+	ut_assert_console_end();
+
+	ut_asserteq(1, run_command("env exists non_default_var2", 0));
+	ut_assert_console_end();
+
+	return 0;
+}
+ENV_TEST(env_test_env_cmd, UT_TESTF_CONSOLE_REC);
+
 int do_ut_env(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
 	struct unit_test *tests = UNIT_TEST_SUITE_START(env_test);