Fix blast radius numbers in the get-change report (#1523)

GitOrigin-RevId: fb9a3978ace7360bf25b0bd491e145976cab093b

Author: tphoney

sdp-go/util.go

@@ -161,6 +161,15 @@ func RenderItemDiff(gun string, before, after map[string]any, changeData, rawDat
 			k := fmt.Sprintf("%v.%v", gun, key)
 			v := attrs[k]
 			slices.Sort(v)
+			v = slices.Compact(v)
+			for i, val := range v {
+				val = strings.ReplaceAll(val, "\n", " ")
+				val = strings.ReplaceAll(val, "\t", " ")
+				if len(val) > 100 {
+					val = val[:100]
+				}
+				v[i] = val
+			}
 
 			if len(v) > 0 {
 				para = append(para, fmt.Sprintf("# → 🔁 This attribute has changed %d times in the last 30 days.\n#      The previous values were %v.", len(v), v))

sdp-go/util_test.go

@@ -175,6 +175,36 @@ func TestItemDiffParagraphRendering(t *testing.T) {
 			},
 			ExpectedDiffParagraph: "",
 		},
+		{
+			Name: "with stats, previous values truncated to 100 characters",
+			Before: map[string]any{
+				"name": map[string]any{
+					"first": "test",
+					"last":  "user",
+				},
+			},
+			After: map[string]any{
+				"name": map[string]any{
+					"first": "test",
+					"last":  "updated",
+				},
+			},
+			ChangeRollups: []RoutineRollup{
+				{
+					Gun:   "testGun",
+					Attr:  "name.last",
+					Value: "user",
+				},
+			},
+			RawRollups: []RoutineRollup{
+				{
+					Gun:   "testGun",
+					Attr:  "name.last",
+					Value: "123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.AAAAAA",
+				},
+			},
+			ExpectedDiffParagraph: "- name.last: user\n+ name.last: updated\n# → 🔁 This attribute has changed 1 times in the last 30 days.\n#      The previous values were [123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.].",
+		},
 	}
 
 	for _, test := range tests {