Regression issue: Allow SSM parameter overwrite upon creation

.changelog/26785.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_ssm_parameter: Allow parameter overwrite on create
+```

internal/service/ssm/parameter.go

@@ -150,6 +150,7 @@ func resourceParameterCreate(d *schema.ResourceData, meta interface{}) error {
 		Name:           aws.String(name),
 		Type:           aws.String(d.Get("type").(string)),
 		Value:          aws.String(value),
+		Overwrite:      aws.Bool(ShouldUpdateParameter(d)),
 		AllowedPattern: aws.String(d.Get("allowed_pattern").(string)),
 	}
 
@@ -169,7 +170,10 @@ func resourceParameterCreate(d *schema.ResourceData, meta interface{}) error {
 		paramInput.SetKeyId(keyID.(string))
 	}
 
-	if len(tags) > 0 {
+	// AWS SSM Service only supports PutParameter requests with Tags
+	// iff Overwrite is not provided or is false; in this resource's case,
+	// the Overwrite value is always set in the paramInput so we check for the value
+	if len(tags) > 0 && !aws.BoolValue(paramInput.Overwrite) {
 		paramInput.Tags = Tags(tags.IgnoreAWS())
 	}
 
@@ -185,6 +189,17 @@ func resourceParameterCreate(d *schema.ResourceData, meta interface{}) error {
 		return fmt.Errorf("error creating SSM Parameter (%s): %w", name, err)
 	}
 
+	// Since the AWS SSM Service does not support PutParameter requests with
+	// Tags and Overwrite set to true, we make an additional API call
+	// to Update the resource's tags if necessary
+	if d.HasChange("tags_all") && paramInput.Tags == nil {
+		o, n := d.GetChange("tags_all")
+
+		if err := UpdateTags(conn, name, ssm.ResourceTypeForTaggingParameter, o, n); err != nil {
+			return fmt.Errorf("error updating SSM Parameter (%s) tags: %w", name, err)
+		}
+	}
+
 	d.SetId(name)
 
 	return resourceParameterRead(d, meta)

internal/service/ssm/parameter_test.go

@@ -285,10 +285,31 @@ func TestAccSSMParameter_Overwrite_basic(t *testing.T) {
 		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
 		CheckDestroy:             testAccCheckParameterDestroy,
 		Steps: []resource.TestStep{
+			{
+
+				PreConfig: func() {
+					conn := acctest.Provider.Meta().(*conns.AWSClient).SSMConn
+
+					input := &ssm.PutParameterInput{
+						Name:  aws.String(fmt.Sprintf("%s-%s", "test_parameter", name)),
+						Type:  aws.String(ssm.ParameterTypeString),
+						Value: aws.String("This value is set using the SDK"),
+					}
+
+					_, err := conn.PutParameter(input)
+					if err != nil {
+						t.Fatalf("creating SSM Parameter: (%s):, %s", name, err)
+					}
+				},
+				Config: testAccParameterConfig_basicOverwrite(name, "String", "This value is set using Terraform"),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(resourceName, "version", "2"),
+				),
+			},
 			{
 				Config: testAccParameterConfig_basicOverwrite(name, "String", "test2"),
 				Check: resource.ComposeTestCheckFunc(
-					resource.TestCheckResourceAttr(resourceName, "version", "1"),
+					resource.TestCheckResourceAttr(resourceName, "version", "3"),
 				),
 			},
 			{
@@ -303,7 +324,7 @@ func TestAccSSMParameter_Overwrite_basic(t *testing.T) {
 					testAccCheckParameterExists(resourceName, &param),
 					resource.TestCheckResourceAttr(resourceName, "value", "test3"),
 					resource.TestCheckResourceAttr(resourceName, "type", "String"),
-					resource.TestCheckResourceAttr(resourceName, "version", "2"),
+					resource.TestCheckResourceAttr(resourceName, "version", "4"),
 				),
 			},
 		},

website/docs/r/ssm_parameter.html.markdown

@@ -10,6 +10,8 @@ description: |-
 
 Provides an SSM Parameter resource.
 
+~> **Note:** `overwrite` also makes it possible to overwrite an existing SSM Parameter that's not created by Terraform before.
+
 ## Example Usage
 
 ### Basic example