Fix crash in custom boost input.

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/subscription/boost/Boost.kt

@@ -266,7 +266,8 @@ data class Boost(
       if (withoutSymbol != withoutLeadingZeroes) {
         text?.removeTextChangedListener(this)
 
-        s.replace(s.indexOf(withoutSymbol), withoutSymbol.length, withoutLeadingZeroes)
+        val start = s.indexOf(withoutSymbol)
+        s.replace(start, start + withoutSymbol.length, withoutLeadingZeroes)
 
         text?.addTextChangedListener(this)
       }

app/src/main/java/org/thoughtcrime/securesms/components/settings/app/subscription/boost/BoostViewModel.kt

@@ -22,6 +22,7 @@ import org.thoughtcrime.securesms.keyvalue.SignalStore
 import org.thoughtcrime.securesms.util.InternetConnectionObserver
 import org.thoughtcrime.securesms.util.PlatformCurrencyUtil
 import org.thoughtcrime.securesms.util.livedata.Store
+import java.lang.NumberFormatException
 import java.math.BigDecimal
 import java.text.DecimalFormat
 import java.text.DecimalFormatSymbols
@@ -201,7 +202,12 @@ class BoostViewModel(
     } else {
       val decimalFormat = DecimalFormat.getInstance() as DecimalFormat
       decimalFormat.isParseBigDecimal = true
-      decimalFormat.parse(amount) as BigDecimal
+
+      try {
+        decimalFormat.parse(amount) as BigDecimal
+      } catch (e: NumberFormatException) {
+        BigDecimal.ZERO
+      }
     }
 
     store.update { it.copy(customAmount = FiatMoney(bigDecimalAmount, it.customAmount.currency)) }

app/src/test/java/org/thoughtcrime/securesms/components/settings/app/subscription/boost/BoostTest__MoneyFilter.kt

@@ -61,6 +61,16 @@ class BoostTest__MoneyFilter {
     assertEquals("5", result)
   }
 
+  @Test
+  fun `Given USD, when I enter 00005dot00, then I expect 5 from text change`() {
+    val testSubject = Boost.MoneyFilter(usd)
+    val editable = SpannableStringBuilder("00005.00")
+
+    testSubject.afterTextChanged(editable)
+
+    assertEquals("$5", editable.toString())
+  }
+
   @Test
   fun `Given USD, when I enter 5dot000, then I expect successful filter`() {
     val testSubject = Boost.MoneyFilter(yen)