Hash-cons Apply, Constant and change node input replacement semantics

aesara/compile/debugmode.py

@@ -14,10 +14,11 @@
 from itertools import chain
 from itertools import product as itertools_product
 from logging import Logger
-from typing import Optional
+from typing import TYPE_CHECKING, Optional, Union
 from warnings import warn
 
 import numpy as np
+from typing_extensions import Literal
 
 import aesara
 from aesara.compile.function.types import (
@@ -42,7 +43,9 @@
 from aesara.utils import NoDuplicateOptWarningFilter, difference, get_unbound_function
 
 
-__docformat__ = "restructuredtext en"
+if TYPE_CHECKING:
+    from aesara.graph.basic import Apply
+
 _logger: Logger = logging.getLogger("aesara.compile.debugmode")
 _logger.addFilter(NoDuplicateOptWarningFilter())
 
@@ -1109,43 +1112,32 @@ class _FunctionGraphEvent:
 
     """
 
-    kind = ""
-    """
-    One of 'import', 'change', 'prune'.
-
-    """
-
-    node = None
-    """
-    Either 'output' or an Apply instance.
-
-    """
-
-    op = None
-    """Either 'output' or an Op instance"""
+    kind: Literal["import", "change", "prune"]
+    old_node: Optional[Union[Literal["output"], "Apply"]]
+    new_node: Optional[Union[Literal["output"], "Apply"]]
+    op: Optional[Union[Literal["output"], Op]]
+    idx: Optional[int]
+    reason: Optional[str]
 
-    idx = None
-    """
-    Change events involve an position index of the input variable.
-
-    """
-
-    reason = None
-    """
-    Change events sometimes have a reason.
-
-    """
-
-    def __init__(self, kind, node, idx=None, reason=None):
+    def __init__(
+        self,
+        kind: Literal["import", "change", "prune"],
+        old_node: Union[Literal["output"], "Apply"],
+        new_node: Union[Literal["output"], "Apply"] = None,
+        idx: Optional[int] = None,
+        reason: Optional[str] = None,
+    ):
         self.kind = kind
-        if node == "output":
-            self.node = "output"
+        if old_node == "output":
+            self.old_node = "output"
+            self.new_node = "output"
             self.op = "output"
         else:
-            self.node = node
-            self.op = node.op
+            self.old_node = old_node
+            self.new_node = new_node
+            self.op = old_node.op
         self.idx = idx
-        self.reason = str(reason)
+        self.reason = str(reason) if reason else None
 
     def __str__(self):
         if self.kind == "change":
@@ -1219,21 +1211,21 @@ def on_attach(self, fgraph):
         self.replaced_by = {}
         self.event_list = []
         for node in fgraph.toposort():
-            self.on_import(fgraph, node, "on_attach")
+            self.on_import(fgraph, node, reason="on_attach")
 
     def on_detach(self, fgraph):
         assert fgraph is self.fgraph
         self.fgraph = None
 
     def on_prune(self, fgraph, node, reason):
-        self.event_list.append(_FunctionGraphEvent("prune", node, reason=str(reason)))
+        self.event_list.append(_FunctionGraphEvent("prune", node, reason=reason))
         assert node in self.active_nodes
         assert node not in self.inactive_nodes
         self.active_nodes.remove(node)
         self.inactive_nodes.add(node)
 
     def on_import(self, fgraph, node, reason):
-        self.event_list.append(_FunctionGraphEvent("import", node, reason=str(reason)))
+        self.event_list.append(_FunctionGraphEvent("import", node, reason=reason))
 
         assert node not in self.active_nodes
         self.active_nodes.add(node)
@@ -1253,31 +1245,36 @@ def on_import(self, fgraph, node, reason):
                 self.reasons.setdefault(r, [])
                 self.replaced_by.setdefault(r, [])
 
-    def on_change_input(self, fgraph, node, i, r, new_r, reason=None):
+    def on_change_input(
+        self, fgraph, old_node, new_node, i, old_var, new_var, reason=None
+    ):
         reason = str(reason)
         self.event_list.append(
-            _FunctionGraphEvent("change", node, reason=reason, idx=i)
+            _FunctionGraphEvent("change", old_node, new_node, idx=i, reason=reason)
         )
 
-        self.reasons.setdefault(new_r, [])
-        self.replaced_by.setdefault(new_r, [])
+        self.on_import(fgraph, new_node, reason=reason)
+        self.on_prune(fgraph, old_node, reason=reason)
+
+        self.reasons.setdefault(new_var, [])
+        self.replaced_by.setdefault(new_var, [])
 
         append_reason = True
-        for tup in self.reasons[new_r]:
-            if tup[0] == reason and tup[1] is r:
+        for tup in self.reasons[new_var]:
+            if tup[0] == reason and tup[1] is old_var:
                 append_reason = False
 
         if append_reason:
             # N.B. compute the debugprint now, because future
             # optimizations will change the graph
             done = dict()
             used_ids = dict()
-            self.reasons[new_r].append(
+            self.reasons[new_var].append(
                 (
                     reason,
-                    r,
+                    old_var,
                     _debugprint(
-                        r,
+                        old_var,
                         prefix="  ",
                         depth=6,
                         file=StringIO(),
@@ -1286,7 +1283,7 @@ def on_change_input(self, fgraph, node, i, r, new_r, reason=None):
                         used_ids=used_ids,
                     ).getvalue(),
                     _debugprint(
-                        new_r,
+                        new_var,
                         prefix="  ",
                         depth=6,
                         file=StringIO(),
@@ -1296,22 +1293,22 @@ def on_change_input(self, fgraph, node, i, r, new_r, reason=None):
                     ).getvalue(),
                 )
             )
-            self.replaced_by[r].append((reason, new_r))
+            self.replaced_by[old_var].append((reason, new_var))
 
-        if r in self.equiv:
-            r_set = self.equiv[r]
+        if old_var in self.equiv:
+            r_set = self.equiv[old_var]
         else:
-            r_set = self.equiv.setdefault(r, {r})
-            self.all_variables_ever.append(r)
+            r_set = self.equiv.setdefault(old_var, {old_var})
+            self.all_variables_ever.append(old_var)
 
-        if new_r in self.equiv:
-            new_r_set = self.equiv[new_r]
+        if new_var in self.equiv:
+            new_r_set = self.equiv[new_var]
         else:
-            new_r_set = self.equiv.setdefault(new_r, {new_r})
-            self.all_variables_ever.append(new_r)
+            new_r_set = self.equiv.setdefault(new_var, {new_var})
+            self.all_variables_ever.append(new_var)
 
-        assert new_r in new_r_set
-        assert r in r_set
+        assert new_var in new_r_set
+        assert old_var in r_set
 
         # update one equivalence set to contain the other
         # transfer all the elements of the old one to the new one
@@ -1320,8 +1317,8 @@ def on_change_input(self, fgraph, node, i, r, new_r, reason=None):
             self.equiv[like_new_r] = r_set
             assert like_new_r in r_set
 
-        assert self.equiv[r] is r_set
-        assert self.equiv[new_r] is r_set
+        assert self.equiv[old_var] is r_set
+        assert self.equiv[new_var] is r_set
 
     def printstuff(self):
         for key in self.equiv: