From a83a010dcbd0a1aeb1828d1d3551f8ea84e4da83 Mon Sep 17 00:00:00 2001
From: rk <rk@garuna.dev>
Date: Wed, 4 Nov 2026 23:29:38 +0500
Subject: [PATCH 1/2] fix(core): keep enum var names unique after renaming
 duplicates

---
 .../org/openapitools/codegen/DefaultCodegen.java |  4 ++++
 .../openapitools/codegen/DefaultCodegenTest.java | 16 ++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 4f52010d72b1..042f3bf844c3 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -7303,6 +7303,10 @@ protected void postProcessEnumVars(List<EnumVarMap> enumVars) {
             }
         });
         Collections.reverse(enumVars);
+        // a new name can already be taken ("EtcGmt1" + "2" is "EtcGmt12"), so repeat until names are unique
+        if (enumVars.stream().map(EnumVarMap::getEnumName).distinct().count() < enumVars.size()) {
+            postProcessEnumVars(enumVars);
+        }
     }
 
     private String getUniqueEnumName(String name, List<EnumVarMap> enumVars) {
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
index 1a7f3780eb88..be8a61aef5ff 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
@@ -84,6 +84,22 @@ public void testBuildEnumVarsPreservesRawValueAlignmentAcrossNulls() {
         Assert.assertEquals(enumVars.get(1).getEnumValue(), "\"_42\"");
     }
 
+    @Test
+    public void testPostProcessEnumVarsKeepsRenamedEntriesUnique() {
+        // typescript names of "Etc/GMT+12", "Etc/GMT+1", "Etc/GMT0", "Etc/GMT-1" and "Etc/GMT-12"
+        List<EnumVarMap> enumVars = new ArrayList<>();
+        for (String name : Arrays.asList("EtcGmt12", "EtcGmt1", "EtcGmt0", "EtcGmt1", "EtcGmt12")) {
+            EnumVarMap enumVar = new EnumVarMap();
+            enumVar.setEnumName(name);
+            enumVars.add(enumVar);
+        }
+
+        new DefaultCodegen().postProcessEnumVars(enumVars);
+
+        assertThat(enumVars).extracting(EnumVarMap::getEnumName)
+                .containsExactly("EtcGmt122", "EtcGmt1", "EtcGmt0", "EtcGmt12", "EtcGmt1222");
+    }
+
     @Test(expectedExceptions = IllegalArgumentException.class)
     public void testBuildEnumVarsRejectsMismatchedRawValues() {
         new DefaultCodegen().buildEnumVars(Collections.singletonList("value"), "string", Collections.emptyList());

From 991fa3bee753f79a326af61b942d7da0d55156f1 Mon Sep 17 00:00:00 2001
From: rk <rk@garuna.dev>
Date: Thu, 5 Nov 2026 00:19:05 +0500
Subject: [PATCH 2/2] fix(core): repeat enum dedupe in a loop

---
 .../openapitools/codegen/DefaultCodegen.java  | 27 +++++++++----------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 042f3bf844c3..4ffb0a4bd810 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -7292,21 +7292,20 @@ protected void removeEnumUnknownDefaultCase(CodegenOperation operation) {
     }
 
     protected void postProcessEnumVars(List<EnumVarMap> enumVars) {
-        Collections.reverse(enumVars);
-        enumVars.forEach(v -> {
-            String name = (String) v.getEnumName();
-            long count = enumVars.stream().filter(v1 -> v1.getEnumName().equals(name)).count();
-            if (count > 1) {
-                String uniqueEnumName = getUniqueEnumName(name, enumVars);
-                LOGGER.debug("Changing duplicate enumeration name from {} to {}", v.getEnumName(), uniqueEnumName);
-                v.setEnumName(uniqueEnumName);
-            }
-        });
-        Collections.reverse(enumVars);
         // a new name can already be taken ("EtcGmt1" + "2" is "EtcGmt12"), so repeat until names are unique
-        if (enumVars.stream().map(EnumVarMap::getEnumName).distinct().count() < enumVars.size()) {
-            postProcessEnumVars(enumVars);
-        }
+        do {
+            Collections.reverse(enumVars);
+            enumVars.forEach(v -> {
+                String name = (String) v.getEnumName();
+                long count = enumVars.stream().filter(v1 -> v1.getEnumName().equals(name)).count();
+                if (count > 1) {
+                    String uniqueEnumName = getUniqueEnumName(name, enumVars);
+                    LOGGER.debug("Changing duplicate enumeration name from {} to {}", v.getEnumName(), uniqueEnumName);
+                    v.setEnumName(uniqueEnumName);
+                }
+            });
+            Collections.reverse(enumVars);
+        } while (enumVars.stream().map(EnumVarMap::getEnumName).distinct().count() < enumVars.size());
     }
 
     private String getUniqueEnumName(String name, List<EnumVarMap> enumVars) {