From 873ecc01475fc11ac201d4a48ce03b02f460d935 Mon Sep 17 00:00:00 2001
From: Jesse Bannon <jbann1994@gmail.com>
Date: Wed, 20 Dec 2023 23:46:17 -0800
Subject: [PATCH] [BUGFIX] Fix recursion limit when applying large reduce
 functions (#851)

Python would think a recursive error occurred, but in reality, the stack got too large due to poor optimization when executing array reduce functions. Thanks Melissa from Discord for the bug report!
---
 src/ytdl_sub/script/types/function.py         | 27 +++++++------
 src/ytdl_sub/utils/scriptable.py              | 12 +++---
 .../script/functions/test_array_functions.py  | 39 +++++++++++++++++++
 3 files changed, 62 insertions(+), 16 deletions(-)

diff --git a/src/ytdl_sub/script/types/function.py b/src/ytdl_sub/script/types/function.py
index 94bbad5d..7d1cea85 100644
--- a/src/ytdl_sub/script/types/function.py
+++ b/src/ytdl_sub/script/types/function.py
@@ -232,20 +232,25 @@ class BuiltInFunction(Function, BuiltInFunctionType):
         if len(lambda_array.value) == 1:
             return lambda_array.value[0]
 
-        reduced = self._instantiate_lambda(
-            lambda_function_name=lambda_function_name,
-            args=[lambda_array.value[0], lambda_array.value[1]],
-        )
-        for idx in range(2, len(lambda_array.value)):
-            reduced = self._instantiate_lambda(
-                lambda_function_name=lambda_function_name, args=[reduced, lambda_array.value[idx]]
-            )
-
-        return self._resolve_argument_type(
-            arg=reduced,
+        reduced: Resolvable = self._resolve_argument_type(
+            arg=self._instantiate_lambda(
+                lambda_function_name=lambda_function_name,
+                args=[lambda_array.value[0], lambda_array.value[1]],
+            ),
             resolved_variables=resolved_variables,
             custom_functions=custom_functions,
         )
+        for idx in range(2, len(lambda_array.value)):
+            reduced = self._resolve_argument_type(
+                arg=self._instantiate_lambda(
+                    lambda_function_name=lambda_function_name,
+                    args=[reduced, lambda_array.value[idx]],
+                ),
+                resolved_variables=resolved_variables,
+                custom_functions=custom_functions,
+            )
+
+        return reduced
 
     def resolve(
         self,
diff --git a/src/ytdl_sub/utils/scriptable.py b/src/ytdl_sub/utils/scriptable.py
index 0dace721..105bce98 100644
--- a/src/ytdl_sub/utils/scriptable.py
+++ b/src/ytdl_sub/utils/scriptable.py
@@ -19,12 +19,14 @@ class Scriptable(ABC):
     Shared class between Entry and Overrides to manage their underlying Script.
     """
 
-    def __init__(self):
-        self.script = Script(
-            ScriptUtils.add_sanitized_variables(
-                dict(copy.deepcopy(VARIABLE_SCRIPTS), **copy.deepcopy(CUSTOM_FUNCTION_SCRIPTS))
-            )
+    _BASE_SCRIPT: Script = Script(
+        ScriptUtils.add_sanitized_variables(
+            dict(copy.deepcopy(VARIABLE_SCRIPTS), **copy.deepcopy(CUSTOM_FUNCTION_SCRIPTS))
         )
+    )
+
+    def __init__(self):
+        self.script = copy.deepcopy(Scriptable._BASE_SCRIPT)
         self.unresolvable: Set[str] = copy.deepcopy(UNRESOLVED_VARIABLES)
 
     def update_script(self) -> None:
diff --git a/tests/unit/script/functions/test_array_functions.py b/tests/unit/script/functions/test_array_functions.py
index d9515d2d..06a3b150 100644
--- a/tests/unit/script/functions/test_array_functions.py
+++ b/tests/unit/script/functions/test_array_functions.py
@@ -58,6 +58,45 @@ class TestArrayFunctions:
         output = single_variable_output("{%array_reduce([1, 2, 3, 4], %add)}")
         assert output == 10
 
+    def test_array_reduce_complex(self):
+        output = (
+            Script(
+                {
+                    "%custom_get": """{
+                        %if(
+                            %bool(siblings_array),
+                            %array_apply_fixed(
+                                siblings_array,
+                                %string($0),
+                                %map_get
+                            )
+                            []
+                        )
+                    }""",
+                    "siblings_array": """{
+                        [
+                            {'upload_date': '20200101'},
+                            {'upload_date': '19940101'}
+                        ]
+                    }""",
+                    "upload_date": "20230101",
+                    "output": """{
+                        %array_reduce(
+                            %if_passthrough(
+                                %custom_get('upload_date'),
+                                [ upload_date ]
+                            ),
+                            %max
+                        )
+                    }""",
+                }
+            )
+            .resolve(update=True)
+            .get("output")
+            .native
+        )
+        assert output == "20200101"
+
     def test_array_enumerate(self):
         output = (
             Script(