From 5bc590c9698ca1bda96364fcc2f4b82528c29ba6 Mon Sep 17 00:00:00 2001
From: Xin Huang <huan233@usc.edu>
Date: Wed, 10 Jun 2026 17:09:32 -0700
Subject: [PATCH] API: Treat default edge algorithm as equal to an omitted one
 in GeographyType

GeographyType used null to mean "default" for both crs and algorithm,
but equals/hashCode/toString compared the raw nullable fields, so
GeographyType.of(crs, EdgeAlgorithm.SPHERICAL) was not equal to the
equivalent GeographyType.of(crs) even though SPHERICAL is the documented
default. A plain geography therefore did not round-trip through format
conversions that omit default values (e.g. Parquet, where an unset
algorithm defaults to SPHERICAL).

Normalize at the comparison/render boundary instead of in the
constructor: equals, hashCode, and toString now use the resolved getters
crs() / algorithm() (which already apply the defaults), so an explicit
default and an omitted one compare equal and render the same. The
constructor is unchanged. CRS already behaved this way; this brings the
algorithm in line.

Co-authored-by: Isaac
---
 .../java/org/apache/iceberg/types/Types.java  |  9 ++++----
 .../org/apache/iceberg/types/TestTypes.java   | 21 +++++++++++++++++++
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/api/src/main/java/org/apache/iceberg/types/Types.java b/api/src/main/java/org/apache/iceberg/types/Types.java
index ec6076b04fa0..24077b13e892 100644
--- a/api/src/main/java/org/apache/iceberg/types/Types.java
+++ b/api/src/main/java/org/apache/iceberg/types/Types.java
@@ -680,18 +680,19 @@ public boolean equals(Object o) {
       }
 
       GeographyType that = (GeographyType) o;
-      return Objects.equals(crs, that.crs) && Objects.equals(algorithm, that.algorithm);
+      // compare the resolved CRS and algorithm so an explicit default is equal to an omitted one
+      return crs().equals(that.crs()) && algorithm() == that.algorithm();
     }
 
     @Override
     public int hashCode() {
-      return Objects.hash(GeographyType.class, crs, algorithm);
+      return Objects.hash(GeographyType.class, crs(), algorithm());
     }
 
     @Override
     public String toString() {
-      if (algorithm != null) {
-        return String.format("geography(%s, %s)", crs != null ? crs : DEFAULT_CRS, algorithm);
+      if (algorithm() != DEFAULT_ALGORITHM) {
+        return String.format("geography(%s, %s)", crs(), algorithm());
       } else if (crs != null) {
         return String.format("geography(%s)", crs);
       } else {
diff --git a/api/src/test/java/org/apache/iceberg/types/TestTypes.java b/api/src/test/java/org/apache/iceberg/types/TestTypes.java
index fa5ed4304d3c..9e6907210477 100644
--- a/api/src/test/java/org/apache/iceberg/types/TestTypes.java
+++ b/api/src/test/java/org/apache/iceberg/types/TestTypes.java
@@ -172,6 +172,27 @@ public void testGeospatialTypeToString() {
         .isEqualTo("geography(srid:4326, karney)");
     assertThat(Types.GeographyType.of(null, EdgeAlgorithm.KARNEY).toString())
         .isEqualTo("geography(OGC:CRS84, karney)");
+    assertThat(Types.GeographyType.of("OGC:CRS84", EdgeAlgorithm.SPHERICAL).toString())
+        .isEqualTo("geography");
+    assertThat(Types.GeographyType.of("srid:4326", EdgeAlgorithm.SPHERICAL).toString())
+        .isEqualTo("geography(srid:4326)");
+  }
+
+  @Test
+  public void testGeospatialTypeDefaultNormalization() {
+    // the default CRS and edge algorithm normalize so that equivalent type specs are equal
+    assertThat(Types.GeometryType.of("OGC:CRS84")).isEqualTo(Types.GeometryType.crs84());
+    assertThat(Types.GeographyType.of("OGC:CRS84")).isEqualTo(Types.GeographyType.crs84());
+    assertThat(Types.GeographyType.of("OGC:CRS84", EdgeAlgorithm.SPHERICAL))
+        .isEqualTo(Types.GeographyType.crs84())
+        .hasSameHashCodeAs(Types.GeographyType.crs84());
+    assertThat(Types.GeographyType.of("srid:4326", EdgeAlgorithm.SPHERICAL))
+        .isEqualTo(Types.GeographyType.of("srid:4326"))
+        .hasSameHashCodeAs(Types.GeographyType.of("srid:4326"));
+    assertThat(Types.GeographyType.of("srid:4326", EdgeAlgorithm.SPHERICAL).algorithm())
+        .isEqualTo(EdgeAlgorithm.SPHERICAL);
+    assertThat(Types.GeographyType.of("srid:4326", EdgeAlgorithm.KARNEY))
+        .isNotEqualTo(Types.GeographyType.of("srid:4326"));
   }
 
   @Test