From 837fa14fe37aab43895cf4a23d0fe34c0919e865 Mon Sep 17 00:00:00 2001
From: "Bogdan.Petranivskyy" <bogdan.petranivskyy@globallogic.com>
Date: Wed, 9 Apr 2025 21:44:50 +0300
Subject: [PATCH] #7: Fix: Prevent double extension when using output directive
 in T4 templates

---
 T4.Build/BuildTemplateGenerator.cs | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/T4.Build/BuildTemplateGenerator.cs b/T4.Build/BuildTemplateGenerator.cs
index a117e62..50d8d57 100644
--- a/T4.Build/BuildTemplateGenerator.cs
+++ b/T4.Build/BuildTemplateGenerator.cs
@@ -39,12 +39,12 @@ string LockPath
 
                 return lockPath;
             }
-        }
-
+        }
+
         public new string OutputFile
-        {
-            get
-            {
+        {
+            get
+            {
                 if (string.IsNullOrEmpty(base.OutputFile))
                 {
                     if (ParsedTemplate == null)
@@ -54,11 +54,11 @@ string LockPath
                     foreach (var dt in ParsedTemplate.Directives)
                     {
                         if (dt.Name == "output")
-                            ext = dt.Attributes.GetValueOrDefault("extension", ext);
-                    }
-                    base.OutputFile = Path.ChangeExtension(TemplateFile, ext);
-                }
-
+                            ext = dt.Attributes.GetValueOrDefault("extension", ext);
+                    }
+                    base.OutputFile = Path.ChangeExtension(TemplateFile, ext);
+                }
+
                 return base.OutputFile;
             }
         }
@@ -114,7 +114,14 @@ public bool ProcessTemplate(bool skipUpToDate, out bool skipped)
                     return true;
                 }
             }
-            return ProcessTemplate(TemplateFile, OutputFile);
+
+            var requestOutputFile = OutputFile;
+            var result = ProcessTemplate(TemplateFile, OutputFile);
+            if (requestOutputFile != OutputFile && File.Exists(OutputFile))
+            {
+                File.Move(OutputFile, requestOutputFile, true);
+            }
+            return result;
         }
 
     }