command/format: fix repetitive "unchanged attribute hidden" message (#28589)

writeNestedAttrDiff and writeAttrDiff were both printing the "unchanged attribute" message.  This removes one of the redundant prints.

Fixing this led me (in a very roundabout way) to realize that NestedType attributes were printing a sum total of unchanged attributes, including those in entirely unchanged elements, while *not* printing the total of unchanged elements. I added the necessary logic to count and print the number of unchanged elements for maps and lists.

command/format/diff.go

@@ -219,6 +219,7 @@ func (p *blockBodyDiffPrinter) writeBlockBodyDiff(schema *configschema.Block, ol
 
 	// write the attributes diff
 	blankBeforeBlocks := p.writeAttrsDiff(schema.Attributes, old, new, indent, path, &result)
+	p.writeSkippedAttr(result.skippedAttributes, indent+2)
 
 	{
 		blockTypeNames := make([]string, 0, len(schema.BlockTypes))
@@ -299,16 +300,6 @@ func (p *blockBodyDiffPrinter) writeAttrsDiff(
 		}
 	}
 
-	if result.skippedAttributes > 0 {
-		noun := "attributes"
-		if result.skippedAttributes == 1 {
-			noun = "attribute"
-		}
-		p.buf.WriteString("\n")
-		p.buf.WriteString(strings.Repeat(" ", indent+2))
-		p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", result.skippedAttributes, noun)))
-	}
-
 	return blankBeforeBlocks
 }
 
@@ -405,17 +396,7 @@ func (p *blockBodyDiffPrinter) writeNestedAttrDiff(
 			p.buf.WriteString(p.color.Color(forcesNewResourceCaption))
 		}
 		p.writeAttrsDiff(objS.Attributes, old, new, indent+2, path, result)
-
+		p.writeSkippedAttr(result.skippedAttributes, indent+4)
-		if result.skippedAttributes > 0 {
-			noun := "attributes"
-			if result.skippedAttributes == 1 {
-				noun = "attribute"
-			}
-			p.buf.WriteString("\n")
-			p.buf.WriteString(strings.Repeat(" ", indent+2))
-			p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", result.skippedAttributes, noun)))
-		}
-
 		p.buf.WriteString("\n")
 		p.buf.WriteString(strings.Repeat(" ", indent))
 		p.buf.WriteString("}")
@@ -444,6 +425,9 @@ func (p *blockBodyDiffPrinter) writeNestedAttrDiff(
 		// of the lists will be presented as either creates (+) or deletes (-)
 		// depending on which list they belong to.
 		var commonLen int
+		// unchanged is the number of unchanged elements
+		var unchanged int
+
 		switch {
 		case len(oldItems) < len(newItems):
 			commonLen = len(oldItems)
@@ -456,25 +440,31 @@ func (p *blockBodyDiffPrinter) writeNestedAttrDiff(
 			newItem := newItems[i]
 			if oldItem.RawEquals(newItem) {
 				action = plans.NoOp
+				unchanged++
 			}
+			if action != plans.NoOp {
 				p.writeAttrsDiff(objS.Attributes, oldItem, newItem, indent+6, path, result)
+				p.writeSkippedAttr(result.skippedAttributes, indent+8)
+				p.buf.WriteString("\n")
+			}
 		}
 		for i := commonLen; i < len(oldItems); i++ {
 			path := append(path, cty.IndexStep{Key: cty.NumberIntVal(int64(i))})
 			oldItem := oldItems[i]
 			newItem := cty.NullVal(oldItem.Type())
 			p.writeAttrsDiff(objS.Attributes, oldItem, newItem, indent+6, path, result)
+			p.buf.WriteString("\n")
 		}
 		for i := commonLen; i < len(newItems); i++ {
 			path := append(path, cty.IndexStep{Key: cty.NumberIntVal(int64(i))})
 			newItem := newItems[i]
 			oldItem := cty.NullVal(newItem.Type())
 			p.writeAttrsDiff(objS.Attributes, oldItem, newItem, indent+6, path, result)
-		}
-
 			p.buf.WriteString("\n")
+		}
 		p.buf.WriteString(strings.Repeat(" ", indent+4))
 		p.buf.WriteString("},\n")
+		p.writeSkippedElems(unchanged, indent+4)
 		p.buf.WriteString(strings.Repeat(" ", indent+2))
 		p.buf.WriteString("]")
 
@@ -548,8 +538,10 @@ func (p *blockBodyDiffPrinter) writeNestedAttrDiff(
 		}
 		sort.Strings(allKeysOrder)
 
-		p.buf.WriteString(" = {")
+		p.buf.WriteString(" = {\n")
 
+		// unchanged tracks the number of unchanged elements
+		unchanged := 0
 		for _, k := range allKeysOrder {
 			var action plans.Action
 			oldValue := oldItems[k]
@@ -565,26 +557,27 @@ func (p *blockBodyDiffPrinter) writeNestedAttrDiff(
 				action = plans.Update
 			default:
 				action = plans.NoOp
+				unchanged++
 			}
 
-			p.buf.WriteString("\n")
+			if action != plans.NoOp {
 				p.buf.WriteString(strings.Repeat(" ", indent+4))
 				p.writeActionSymbol(action)
-
 				fmt.Fprintf(p.buf, "%q = {", k)
-			if action != plans.NoOp && (p.pathForcesNewResource(path) || p.pathForcesNewResource(path[:len(path)-1])) {
+				if p.pathForcesNewResource(path) || p.pathForcesNewResource(path[:len(path)-1]) {
 					p.buf.WriteString(p.color.Color(forcesNewResourceCaption))
 				}
 
 				path := append(path, cty.IndexStep{Key: cty.StringVal(k)})
-
 				p.writeAttrsDiff(objS.Attributes, oldValue, newValue, indent+6, path, result)
+				p.writeSkippedAttr(result.skippedAttributes, indent+8)
 				p.buf.WriteString("\n")
 				p.buf.WriteString(strings.Repeat(" ", indent+4))
-			p.buf.WriteString("},")
+				p.buf.WriteString("},\n")
+			}
 		}
 
-		p.buf.WriteString("\n")
+		p.writeSkippedElems(unchanged, indent+4)
 		p.buf.WriteString(strings.Repeat(" ", indent+2))
 		p.buf.WriteString("}")
 	}
@@ -1836,3 +1829,27 @@ func DiffActionSymbol(action plans.Action) string {
 func identifyingAttribute(name string, attrSchema *configschema.Attribute) bool {
 	return name == "id" || name == "tags" || name == "name"
 }
+
+func (p *blockBodyDiffPrinter) writeSkippedAttr(skipped, indent int) {
+	if skipped > 0 {
+		noun := "attributes"
+		if skipped == 1 {
+			noun = "attribute"
+		}
+		p.buf.WriteString("\n")
+		p.buf.WriteString(strings.Repeat(" ", indent))
+		p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", skipped, noun)))
+	}
+}
+
+func (p *blockBodyDiffPrinter) writeSkippedElems(skipped, indent int) {
+	if skipped > 0 {
+		noun := "elements"
+		if skipped == 1 {
+			noun = "element"
+		}
+		p.buf.WriteString(strings.Repeat(" ", indent))
+		p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", skipped, noun)))
+		p.buf.WriteString("\n")
+	}
+}

command/format/diff_test.go

@@ -2309,6 +2309,10 @@ func TestResourceChange_nestedList(t *testing.T) {
 						"mount_point": cty.StringVal("/var/diska"),
 						"size":        cty.NullVal(cty.String),
 					}),
+					cty.ObjectVal(map[string]cty.Value{
+						"mount_point": cty.StringVal("/var/diskb"),
+						"size":        cty.StringVal("50GB"),
+					}),
 				}),
 				"root_block_device": cty.ListVal([]cty.Value{
 					cty.ObjectVal(map[string]cty.Value{
@@ -2325,6 +2329,10 @@ func TestResourceChange_nestedList(t *testing.T) {
 						"mount_point": cty.StringVal("/var/diska"),
 						"size":        cty.StringVal("50GB"),
 					}),
+					cty.ObjectVal(map[string]cty.Value{
+						"mount_point": cty.StringVal("/var/diskb"),
+						"size":        cty.StringVal("50GB"),
+					}),
 				}),
 				"root_block_device": cty.ListVal([]cty.Value{
 					cty.ObjectVal(map[string]cty.Value{
@@ -2343,6 +2351,7 @@ func TestResourceChange_nestedList(t *testing.T) {
             + size        = "50GB"
               # (1 unchanged attribute hidden)
           },
+          # (1 unchanged element hidden)
         ]
         id    = "i-02ae66f368e8518a9"
 
@@ -2992,9 +3001,7 @@ func TestResourceChange_nestedMap(t *testing.T) {
             + mount_point = "/var/disk2"
             + size        = "50GB"
           },
-            "disk_a" = {
+          # (1 unchanged element hidden)
-              # (2 unchanged attributes hidden)
-          },
         }
         id    = "i-02ae66f368e8518a9"
 
@@ -4019,6 +4026,51 @@ func TestResourceChange_sensitiveVariable(t *testing.T) {
       ~ ami = (sensitive value) # forces replacement
         id  = "i-02ae66f368e8518a9"
     }
+`,
+		},
+		"update with sensitive nested type attribute forcing replacement": {
+			Action: plans.DeleteThenCreate,
+			Mode:   addrs.ManagedResourceMode,
+			Before: cty.ObjectVal(map[string]cty.Value{
+				"id": cty.StringVal("i-02ae66f368e8518a9"),
+				"conn_info": cty.ObjectVal(map[string]cty.Value{
+					"user":     cty.StringVal("not-secret"),
+					"password": cty.StringVal("top-secret"),
+				}),
+			}),
+			After: cty.ObjectVal(map[string]cty.Value{
+				"id": cty.StringVal("i-02ae66f368e8518a9"),
+				"conn_info": cty.ObjectVal(map[string]cty.Value{
+					"user":     cty.StringVal("not-secret"),
+					"password": cty.StringVal("new-secret"),
+				}),
+			}),
+			Schema: &configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"id": {Type: cty.String, Optional: true, Computed: true},
+					"conn_info": {
+						NestedType: &configschema.Object{
+							Nesting: configschema.NestingSingle,
+							Attributes: map[string]*configschema.Attribute{
+								"user":     {Type: cty.String, Optional: true},
+								"password": {Type: cty.String, Optional: true, Sensitive: true},
+							},
+						},
+					},
+				},
+			},
+			RequiredReplace: cty.NewPathSet(
+				cty.GetAttrPath("conn_info"),
+				cty.GetAttrPath("password"),
+			),
+			ExpectedOutput: `  # test_instance.example must be replaced
+-/+ resource "test_instance" "example" {
+      ~ conn_info = { # forces replacement
+        ~ password = (sensitive value)
+          # (1 unchanged attribute hidden)
+      }
+        id        = "i-02ae66f368e8518a9"
+    }
 `,
 		},
 	}