feat: ice cli partitions

.gitignore

@@ -1,3 +1,4 @@
+.idea/
 target
 /demo/data
 /demo/clickhouse-udfs.xml

ice/src/main/java/com/altinity/ice/cli/Main.java

@@ -21,6 +21,7 @@
 import com.altinity.ice.cli.internal.cmd.DescribeParquet;
 import com.altinity.ice.cli.internal.cmd.Insert;
 import com.altinity.ice.cli.internal.cmd.InsertWatch;
+import com.altinity.ice.cli.internal.cmd.ListPartitions;
 import com.altinity.ice.cli.internal.cmd.Scan;
 import com.altinity.ice.cli.internal.config.Config;
 import com.altinity.ice.cli.internal.iceberg.rest.RESTCatalogFactory;
@@ -594,6 +595,23 @@ void scanTable(
     }
   }
 
+  @CommandLine.Command(name = "list-partitions", description = "List partitions in a table.")
+  void listPartitions(
+      @CommandLine.Parameters(
+              arity = "1",
+              paramLabel = "<name>",
+              description = "Table name (e.g. ns1.table1)")
+          String name,
+      @CommandLine.Option(
+              names = {"--json"},
+              description = "Output JSON instead of YAML")
+          boolean json)
+      throws IOException {
+    try (RESTCatalog catalog = loadCatalog()) {
+      ListPartitions.run(catalog, TableIdentifier.parse(name), json);
+    }
+  }
+
   @CommandLine.Command(name = "delete-table", description = "Delete table.")
   void deleteTable(
       @CommandLine.Parameters(

ice/src/main/java/com/altinity/ice/cli/internal/cmd/ListPartitions.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2025 Altinity Inc and/or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+package com.altinity.ice.cli.internal.cmd;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.TreeSet;
+import org.apache.iceberg.FileScanTask;
+import org.apache.iceberg.PartitionField;
+import org.apache.iceberg.PartitionSpec;
+import org.apache.iceberg.catalog.TableIdentifier;
+import org.apache.iceberg.io.CloseableIterable;
+import org.apache.iceberg.rest.RESTCatalog;
+
+public final class ListPartitions {
+
+  private ListPartitions() {}
+
+  public static void run(RESTCatalog catalog, TableIdentifier tableId, boolean json)
+      throws IOException {
+    org.apache.iceberg.Table table = catalog.loadTable(tableId);
+    PartitionSpec spec = table.spec();
+
+    if (!spec.isPartitioned()) {
+      var result = new Result(tableId.toString(), List.of(), List.of());
+      output(result, json);
+      return;
+    }
+
+    List<PartitionFieldInfo> partitionSpec = new ArrayList<>();
+    for (PartitionField field : spec.fields()) {
+      String sourceColumn = table.schema().findField(field.sourceId()).name();
+      partitionSpec.add(
+          new PartitionFieldInfo(sourceColumn, field.name(), field.transform().toString()));
+    }
+
+    TreeSet<String> partitionPaths = new TreeSet<>();
+    try (CloseableIterable<FileScanTask> tasks = table.newScan().planFiles()) {
+      for (FileScanTask task : tasks) {
+        String path = spec.partitionToPath(task.file().partition());
+        partitionPaths.add(path);
+      }
+    }
+
+    var result = new Result(tableId.toString(), partitionSpec, new ArrayList<>(partitionPaths));
+    output(result, json);
+  }
+
+  private static void output(Result result, boolean json) throws IOException {
+    ObjectMapper mapper =
+        json
+            ? new ObjectMapper()
+            : new ObjectMapper(new YAMLFactory().enable(YAMLGenerator.Feature.MINIMIZE_QUOTES));
+    mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
+    System.out.println(mapper.writeValueAsString(result));
+  }
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  record Result(String table, List<PartitionFieldInfo> partitionSpec, List<String> partitions) {}
+
+  record PartitionFieldInfo(String sourceColumn, String name, String transform) {}
+}