Merge patch series "teach 'env default' to optionally keep runtime variables"

Rasmus Villemoes <ravi@prevas.dk> says:

Doing bringup of a board, part of my bootstrap logic is in U-Boot. So
when tweaking that logic, I was bitten by a previous completed
bootstrap having left a copy of the environment on the device, which
was imported and thus overrided the new logic.

So I thought, "ok, I'll just make sure to put 'env default -a' as the
first part of the bootstrap logic so I'm not bitten again". Alas, my
logic also relies on certain variables that are set by C code
(e.g. for detecting board variant), and doing 'env default -a' also
eliminates those.

Looking around, the hashtab code already supports a flag that does
exactly what I need, and exposing that is (morally) a one-liner.

Link: https://lore.kernel.org/r/20241030213404.2894247-1-ravi@prevas.dk

2 files changed, 48 insertions, 5 deletions

diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index 392f90f8698..1f259801293 100644
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -523,6 +523,9 @@ static int do_env_default(struct cmd_tbl *cmdtp, int flag,
 			case 'f':		/* force */
 				env_flag |= H_FORCE;
 				break;
+			case 'k':
+				env_flag |= H_NOCLEAR;
+				break;
 			default:
 				return cmd_usage(cmdtp);
 			}
@@ -1133,8 +1136,9 @@ U_BOOT_LONGHELP(env,
 #if defined(CONFIG_CMD_ENV_CALLBACK)
 	"callbacks - print callbacks and their associated variables\nenv "
 #endif
-	"default [-f] -a - [forcibly] reset default environment\n"
-	"env default [-f] var [...] - [forcibly] reset variable(s) to their default values\n"
+	"default [-k] [-f] -a - [forcibly] reset default environment\n"
+	"env default [-k] [-f] var [...] - [forcibly] reset variable(s) to their default values\n"
+	"      \"-k\": keep variables not defined in default environment\n"
 	"env delete [-f] var [...] - [forcibly] delete variable(s)\n"
 #if defined(CONFIG_CMD_EDITENV)
 	"env edit name - edit environment variable\n"
diff --git a/test/env/cmd_ut_env.c b/test/env/cmd_ut_env.c
index 4af05764fb8..9f16a978f2a 100644
--- a/test/env/cmd_ut_env.c
+++ b/test/env/cmd_ut_env.c
@@ -14,16 +14,54 @@ 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_assertok(run_command("setenv non_default_var2 2", 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_assertok(run_command("env default non_default_var1", 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(0, run_command("env exists non_default_var2", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("setenv non_default_var1 3", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("env default -k non_default_var1", 0));
+	ut_assert_console_end();
+
+	ut_asserteq(0, run_command("env exists non_default_var1", 0));
+	ut_assert_console_end();
+
+	ut_asserteq(0, run_command("env exists non_default_var2", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("env default -k -a -f", 0));
+	ut_assert_nextline("## Resetting to default environment");
+	ut_assert_console_end();
+
+	ut_asserteq(0, run_command("env exists non_default_var1", 0));
+	ut_assert_console_end();
+
+	ut_asserteq(0, run_command("env exists non_default_var2", 0));
+	ut_assert_console_end();
+
+	/*
+	 * While the following test of "env default -a" by itself
+	 * works, it unfortunately causes an unrelated test case,
+	 * env_test_fdt_import(), to fail, because the "from_fdt"
+	 * variable would be removed.
+	 */
+#if 0
+	ut_assertok(run_command("env default -a", 0));
+	ut_assert_nextline("## Resetting to default environment");
 	ut_assert_console_end();
 
 	ut_asserteq(1, run_command("env exists non_default_var1", 0));
@@ -31,6 +69,7 @@ static int env_test_env_cmd(struct unit_test_state *uts)
 
 	ut_asserteq(1, run_command("env exists non_default_var2", 0));
 	ut_assert_console_end();
+#endif
 
 	return 0;
 }