sdpython · sdpython · Mar 6, 2026 · Mar 3, 2026 · Mar 3, 2026 · Mar 6, 2026
diff --git a/CHANGELOGS.rst b/CHANGELOGS.rst
@@ -4,6 +4,7 @@ Change Logs
 0.4.2
 +++++
 
+* :pr:`48`: Cache gdot script execution results in Sphinx environment`
 * :pr:`47`: use svg by default with gdot
 
 0.4.1

diff --git a/_unittests/ut_gdot/test_gdot_extension.py b/_unittests/ut_gdot/test_gdot_extension.py
@@ -146,6 +146,36 @@ def test_gdot4_png(self):
             return
         self.assertIn("png", content)
 
+    @ignore_warnings(PendingDeprecationWarning)
+    def test_gdot_script_cache(self):
+        """Test that identical scripts are cached and produce the same output."""
+        script = "print('digraph foo { HbarH -> HbazH; }')".replace("H", '"')
+        content = f"""
+before
+
+.. gdot::
+    :script:
+
+    {script}
+
+middle
+
+.. gdot::
+    :script:
+
+    {script}
+
+after
+"""
+        content = rst2html(
+            content, writer_name="rst", new_extensions=["sphinx_runpython.gdot"]
+        )
+        # Both gdot directives should produce the same DOT output
+        count = content.count('digraph foo { "bar" -> "baz"; }')
+        self.assertEqual(
+            count, 2, f"Expected the DOT code to appear twice, got {count}"
+        )
+
 
 if __name__ == "__main__":
     unittest.main(verbosity=2)
diff --git a/sphinx_runpython/gdot/sphinx_gdot_extension.py b/sphinx_runpython/gdot/sphinx_gdot_extension.py
@@ -1,3 +1,4 @@
+import hashlib
 import os
 import logging
 from docutils import nodes
@@ -153,7 +154,21 @@ def run(self):
         # executes script if any
         content = "\n".join(self.content)
         if script or script == "":
-            stdout, stderr, _ = run_python_script(content, process=process)
+            env = info.get("env")
+            cache_key = hashlib.sha256(f"{content}:{process}".encode()).hexdigest()
+            if env is not None:
+                if not hasattr(env, "gdot_script_cache"):
+                    env.gdot_script_cache = {}
+                cached = env.gdot_script_cache.get(cache_key, None)
+            else:
+                cached = None
+
+            if cached is not None:
+                stdout, stderr = cached
+            else:
+                stdout, stderr, _ = run_python_script(content, process=process)
+                if env is not None:
+                    env.gdot_script_cache[cache_key] = (stdout, stderr)
 
             if stderr:
                 out = [
-Original file line number
+Diff line change
@@ Expand Up / @@ -4,6 +4,7 @@ Change Logs @@
 .4.2
     +++++
+    * :pr:`48`: Cache gdot script execution results in Sphinx environment`
     * :pr:`47`: use svg by default with gdot
 .4.1
@@ Expand Down @@