chore(operators): Add proper descriptions to text source fields

common/workflow-operator/src/main/scala/org/apache/texera/amber/operator/source/scan/text/TextInputSourceOpDesc.scala

@@ -19,7 +19,7 @@
 
 package org.apache.texera.amber.operator.source.scan.text
 
-import com.fasterxml.jackson.annotation.JsonProperty
+import com.fasterxml.jackson.annotation.{JsonProperty, JsonPropertyDescription}
 import com.kjetland.jackson.jsonSchema.annotations.{JsonSchemaInject, JsonSchemaTitle}
 import org.apache.texera.amber.core.executor.OpExecWithClassName
 import org.apache.texera.amber.core.tuple.Schema
@@ -34,6 +34,7 @@ class TextInputSourceOpDesc extends SourceOperatorDescriptor with TextSourceOpDe
   @JsonProperty(required = true)
   @JsonSchemaTitle("Text")
   @JsonSchemaInject(json = UIWidget.UIWidgetTextArea)
+  @JsonPropertyDescription("Enter the input text. By default, each line becomes one tuple.")
   var textInput: String = _
 
   override def getPhysicalOp(

common/workflow-operator/src/main/scala/org/apache/texera/amber/operator/source/scan/text/TextSourceOpDesc.scala

@@ -19,7 +19,7 @@
 
 package org.apache.texera.amber.operator.source.scan.text
 
-import com.fasterxml.jackson.annotation.JsonProperty
+import com.fasterxml.jackson.annotation.{JsonProperty, JsonPropertyDescription}
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize
 import com.kjetland.jackson.jsonSchema.annotations.{
   JsonSchemaInject,
@@ -37,15 +37,23 @@ import org.apache.texera.amber.operator.source.scan.FileAttributeType
 trait TextSourceOpDesc {
   @JsonProperty(defaultValue = "string", required = true)
   @JsonSchemaTitle("Attribute Type")
+  @JsonPropertyDescription(
+    "The output field type. Each line becomes a separate tuple, except for " +
+      "'single string' / 'binary' / 'large binary', where the entire text becomes one tuple."
+  )
   var attributeType: FileAttributeType = FileAttributeType.STRING
 
   @JsonProperty(defaultValue = "line", required = true)
   @JsonSchemaTitle("Attribute Name")
   @JsonDeserialize(contentAs = classOf[java.lang.String])
   var attributeName: String = "line"
 
-  @JsonSchemaTitle("Limit")
+  @JsonSchemaTitle("Limit (lines)")
   @JsonDeserialize(contentAs = classOf[Int])
+  @JsonPropertyDescription(
+    "Maximum number of lines to output. Leave empty to read all lines. " +
+      "(Ignored when reading the whole file as one tuple.)"
+  )
   @JsonSchemaInject(
     strings = Array(
       new JsonSchemaString(path = HideAnnotation.hideTarget, value = "attributeType"),
@@ -58,7 +66,11 @@ trait TextSourceOpDesc {
   )
   var fileScanLimit: Option[Int] = None
 
-  @JsonSchemaTitle("Offset")
+  @JsonSchemaTitle("Offset (lines)")
+  @JsonPropertyDescription(
+    "Number of lines to skip from the start before reading. " +
+      "(Ignored when reading the whole file as one tuple.)"
+  )
   @JsonDeserialize(contentAs = classOf[Int])
   @JsonSchemaInject(
     strings = Array(

frontend/src/app/workspace/component/property-editor/operator-property-edit-frame/operator-property-edit-frame.component.scss

@@ -60,6 +60,13 @@
     nz-input-number {
       width: 100%;
     }
+    // preserve newlines (\n) in property descriptions rendered via nzExtra,
+    // and give them breathing room from the input above
+    .ant-form-item-extra {
+      white-space: pre-line;
+      margin-top: 6px;
+      line-height: 1.4;
+    }
   }
 }