Add diagnostic messages

Author: dkhalanskyjb

core/common/src/internal/format/FieldFormatDirective.kt

@@ -48,7 +48,9 @@ internal abstract class UnsignedIntFieldFormatDirective<in Target>(
     private val maxDigits: Int = field.maxDigits
 
     init {
-        require(minDigits >= 0)
+        require(minDigits >= 0) {
+            "The minimum number of digits ($minDigits) is negative"
+        }
         require(maxDigits >= minDigits) {
             "The maximum number of digits ($maxDigits) is less than the minimum number of digits ($minDigits)"
         }
@@ -151,7 +153,9 @@ internal abstract class StringFieldFormatDirective<in Target>(
 ) : FieldFormatDirective<Target> {
 
     init {
-        require(acceptedStrings.isNotEmpty())
+        require(acceptedStrings.isNotEmpty()) {
+            "The set of accepted strings is empty"
+        }
     }
 
     override fun formatter(): FormatterStructure<Target> =
@@ -173,8 +177,10 @@ internal abstract class SignedIntFieldFormatDirective<in Target>(
 ) : FieldFormatDirective<Target> {
 
     init {
-        require(minDigits == null || minDigits >= 0)
-        require(maxDigits == null || minDigits == null || maxDigits >= minDigits)
+        require(minDigits == null || minDigits >= 0) { "The minimum number of digits ($minDigits) is negative" }
+        require(maxDigits == null || minDigits == null || maxDigits >= minDigits) {
+            "The maximum number of digits ($maxDigits) is less than the minimum number of digits ($minDigits)"
+        }
     }
 
     override fun formatter(): FormatterStructure<Target> {

core/common/src/internal/format/formatter/FormatterOperation.kt

@@ -23,8 +23,8 @@ internal class UnsignedIntFormatterStructure<in T>(
 ): FormatterStructure<T> {
 
     init {
-        require(zeroPadding >= 0)
-        require(zeroPadding <= 9)
+        require(zeroPadding >= 0) { "The minimum number of digits ($zeroPadding) is negative" }
+        require(zeroPadding <= 9) { "The minimum number of digits ($zeroPadding) exceeds the length of an Int" }
     }
 
     override fun format(obj: T, builder: Appendable, minusNotRequired: Boolean) {
@@ -42,8 +42,8 @@ internal class SignedIntFormatterStructure<in T>(
 ): FormatterStructure<T> {
 
     init {
-        require(zeroPadding >= 0)
-        require(zeroPadding <= 9)
+        require(zeroPadding >= 0) { "The minimum number of digits ($zeroPadding) is negative" }
+        require(zeroPadding <= 9) { "The minimum number of digits ($zeroPadding) exceeds the length of an Int" }
     }
 
     override fun format(obj: T, builder: Appendable, minusNotRequired: Boolean) {
@@ -74,8 +74,12 @@ internal class DecimalFractionFormatterStructure<in T>(
 ): FormatterStructure<T> {
 
     init {
-        require(minDigits in 1..9)
-        require(maxDigits in minDigits..9)
+        require(minDigits in 1..9) {
+            "The minimum number of digits ($minDigits) is not in range 1..9"
+        }
+        require(maxDigits in minDigits..9) {
+            "The maximum number of digits ($maxDigits) is not in range $minDigits..9"
+        }
     }
 
     override fun format(obj: T, builder: Appendable, minusNotRequired: Boolean) {

core/common/src/internal/format/parser/ParserOperation.kt

@@ -15,8 +15,8 @@ internal interface ParserOperation<in Output> {
 internal class PlainStringParserOperation<Output>(val string: String) : ParserOperation<Output> {
     init {
         require(string.isNotEmpty()) { "Empty string is not allowed" }
-        require(!string[0].isDigit())
-        require(!string[string.length - 1].isDigit())
+        require(!string[0].isDigit()) { "String '$string' starts with a digit" }
+        require(!string[string.length - 1].isDigit()) { "String '$string' ends with a digit" }
     }
 
     override fun consume(storage: Output, input: CharSequence, startIndex: Int): ParseResult {