From 3ea049d643db534071fab4f576c39d34f2f856c6 Mon Sep 17 00:00:00 2001
From: Robert Newson <rnewson@apache.org>
Date: Tue, 25 Apr 2023 09:41:43 +0100
Subject: allow PUT to existing index if definition identical

---
 .../couchdb/nouveau/api/IndexDefinition.java       | 31 ++++++++++++++++++++++
 .../apache/couchdb/nouveau/core/IndexManager.java  | 10 +++++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/nouveau/src/main/java/org/apache/couchdb/nouveau/api/IndexDefinition.java b/nouveau/src/main/java/org/apache/couchdb/nouveau/api/IndexDefinition.java
index 7d3919c41..3e0f08d64 100644
--- a/nouveau/src/main/java/org/apache/couchdb/nouveau/api/IndexDefinition.java
+++ b/nouveau/src/main/java/org/apache/couchdb/nouveau/api/IndexDefinition.java
@@ -61,6 +61,37 @@ public class IndexDefinition {
         return fieldAnalyzers != null && !fieldAnalyzers.isEmpty();
     }
 
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((defaultAnalyzer == null) ? 0 : defaultAnalyzer.hashCode());
+        result = prime * result + ((fieldAnalyzers == null) ? 0 : fieldAnalyzers.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        IndexDefinition other = (IndexDefinition) obj;
+        if (defaultAnalyzer == null) {
+            if (other.defaultAnalyzer != null)
+                return false;
+        } else if (!defaultAnalyzer.equals(other.defaultAnalyzer))
+            return false;
+        if (fieldAnalyzers == null) {
+            if (other.fieldAnalyzers != null)
+                return false;
+        } else if (!fieldAnalyzers.equals(other.fieldAnalyzers))
+            return false;
+        return true;
+    }
+
     @Override
     public String toString() {
         return "IndexDefinition [defaultAnalyzer=" + defaultAnalyzer
diff --git a/nouveau/src/main/java/org/apache/couchdb/nouveau/core/IndexManager.java b/nouveau/src/main/java/org/apache/couchdb/nouveau/core/IndexManager.java
index ddc7c3f7f..f662780bb 100644
--- a/nouveau/src/main/java/org/apache/couchdb/nouveau/core/IndexManager.java
+++ b/nouveau/src/main/java/org/apache/couchdb/nouveau/core/IndexManager.java
@@ -125,8 +125,13 @@ public final class IndexManager implements Managed {
         }
     }
 
-    public void create(final String name, IndexDefinition indexDefinition) throws IOException {
+    public void create(final String name, IndexDefinition newIndexDefinition) throws IOException {
         if (exists(name)) {
+            final IndexDefinition currentIndexDefinition = loadIndexDefinition(name);
+            if (newIndexDefinition.equals(currentIndexDefinition)) {
+                // Idempotent success.
+                return;
+            }
             throw new WebApplicationException("Index already exists", Status.EXPECTATION_FAILED);
         }
         // Validate index definiton
@@ -134,11 +139,12 @@ public final class IndexManager implements Managed {
 
         // Persist definition
         final Path path = indexDefinitionPath(name);
+
         if (Files.exists(path)) {
             throw new FileAlreadyExistsException(name + " already exists");
         }
         Files.createDirectories(path.getParent());
-        objectMapper.writeValue(path.toFile(), indexDefinition);
+        objectMapper.writeValue(path.toFile(), newIndexDefinition);
     }
 
     public boolean exists(final String name) {
-- 
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