From e31bf410ea4e9689d890faa81290aa1ac334a23a Mon Sep 17 00:00:00 2001
From: Javier de la Torre <jatorre@carto.com>
Date: Sat, 4 Jul 2026 13:29:08 +0200
Subject: [PATCH] fix(go): geo type auto-detect should not require
 edges:spherical for GEOGRAPHY

resolveGeoType's documented contract (and the original #117 semantics) says
'missing CRS, EPSG:4326, or unparsable CRS stays GEOGRAPHY', but the code
required edges == "spherical" as well. Most GeoArrow producers (DuckDB,
GeoPandas) emit a crs with no edges field, so all WGS84 data silently
demoted to GEOMETRY on ingest.

Auto-detect now resolves: SRID 4326 or no CRS -> GEOGRAPHY; any other
SRID -> GEOMETRY (SRID survives the round trip); edges:spherical with a
non-4326 SRID remains an error. Explicit ingest_geo_type is unchanged.

Claude-Session: https://claude.ai/code/session_01Y3xqZXWrx9qXdPNXBzNxa2
---
 go/docs/snowflake.md |  2 +-
 go/statement.go      | 12 +++++++++---
 go/statement_test.go | 12 +++++++++---
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/go/docs/snowflake.md b/go/docs/snowflake.md
index 7425398..1f99f8a 100644
--- a/go/docs/snowflake.md
+++ b/go/docs/snowflake.md
@@ -366,7 +366,7 @@ Examples:
 `adbc.snowflake.statement.ingest_geo_type`
 : **Values:** `geography`, `geometry`, or empty string. **Default:** empty string
 
-  Which Snowflake data type to use when ingesting columns of GeoArrow extension types (`geoarrow.wkb`, `geoarrow.wkt`). If empty, then it will be detected: if the SRID is 4326 and `edges:spherical` is set, then it will be ingested as GEOGRAPHY, else GEOMETRY. If explicitly set, the driver will use the specified type.
+  Which Snowflake data type to use when ingesting columns of GeoArrow extension types (`geoarrow.wkb`, `geoarrow.wkt`). If empty, the type is detected per column from the CRS metadata: columns with SRID 4326 (or no CRS at all) are ingested as GEOGRAPHY, columns with any other SRID as GEOMETRY (so the SRID survives the round trip), and `edges:spherical` combined with a non-4326 SRID is an error. Most GeoArrow producers (e.g. DuckDB, GeoPandas) emit a `crs` but no `edges` field, so detection does not require `edges:spherical` for WGS84 data. If explicitly set, the driver uses the specified type for all GeoArrow columns.
 
   Can be set on the statement.
 
diff --git a/go/statement.go b/go/statement.go
index b78d5d3..796ebb4 100644
--- a/go/statement.go
+++ b/go/statement.go
@@ -740,9 +740,7 @@ func (opts *ingestOptions) resolveGeoType(fieldIndex int, fieldName string, extM
 		return opts.geoType, nil
 	}
 	srid, edges := extractSRIDFromMeta(extMeta)
-	if srid == 4326 && edges == "spherical" {
-		return "geography", nil
-	} else if edges == "spherical" {
+	if edges == "spherical" && srid != 0 && srid != 4326 {
 		// Snowflake GEOGRAPHY is always SRID 4326, so if the user
 		// specified spherical edges but a different SRID, we should
 		// error/ask them to explicitly set the geo type
@@ -751,6 +749,14 @@ func (opts *ingestOptions) resolveGeoType(fieldIndex int, fieldName string, extM
 			Code: adbc.StatusInvalidData,
 		}
 	}
+	// Missing CRS, EPSG:4326, or an unparsable CRS defaults to GEOGRAPHY, as
+	// documented above — most GeoArrow producers (e.g. DuckDB) emit a crs but
+	// no "edges" field, and requiring edges == "spherical" would silently
+	// demote WGS84 data to GEOMETRY. Only a concrete non-4326 SRID promotes
+	// the column so the SRID survives the round trip.
+	if srid == 0 || srid == 4326 {
+		return "geography", nil
+	}
 	return "geometry", nil
 }
 
diff --git a/go/statement_test.go b/go/statement_test.go
index 4b5bc30..7a654cd 100644
--- a/go/statement_test.go
+++ b/go/statement_test.go
@@ -222,9 +222,13 @@ func TestExtractSRIDFromMeta(t *testing.T) {
 func TestResolveGeoType(t *testing.T) {
 	opts := &ingestOptions{}
 
+	// EPSG:4326 without an "edges" field stays GEOGRAPHY: most GeoArrow
+	// producers (DuckDB, GeoPandas) emit a crs but no edges, and WGS84 data
+	// should not silently demote to GEOMETRY (matches the documented
+	// contract of resolveGeoType).
 	ty, err := opts.resolveGeoType(0, "geom", `{"crs":"EPSG:4326"}`)
 	assert.NoError(t, err)
-	assert.Equal(t, "geometry", ty)
+	assert.Equal(t, "geography", ty)
 
 	ty, err = opts.resolveGeoType(0, "geom", `{"crs":"EPSG:3857"}`)
 	assert.NoError(t, err)
@@ -237,13 +241,15 @@ func TestResolveGeoType(t *testing.T) {
 	_, err = opts.resolveGeoType(0, "geom", `{"crs":"EPSG:3857", "edges":"spherical"}`)
 	assert.ErrorContains(t, err, `field #1 ("geom") is a GeoArrow array with spherical edges`)
 
+	// Missing or empty CRS metadata also stays GEOGRAPHY per the documented
+	// default.
 	ty, err = opts.resolveGeoType(0, "geom", "")
 	assert.NoError(t, err)
-	assert.Equal(t, "geometry", ty)
+	assert.Equal(t, "geography", ty)
 
 	ty, err = opts.resolveGeoType(0, "geom", "{}")
 	assert.NoError(t, err)
-	assert.Equal(t, "geometry", ty)
+	assert.Equal(t, "geography", ty)
 
 	// explicit geoType should override CRS-derived default
 	opts.geoType = "geometry"