From 9d319df8eb687503d133277549d25ab7b4c0d1e4 Mon Sep 17 00:00:00 2001
From: Aaron Voelker <aaron.voelker@appliedbrainresearch.com>
Date: Fri, 1 May 2020 17:06:48 -0400
Subject: [PATCH] Truncate semantic pointer names to 1 KB

Fixes #244.
---
 CHANGES.rst                              | 6 ++++++
 nengo_spa/semantic_pointer.py            | 5 +++++
 nengo_spa/tests/test_semantic_pointer.py | 6 ++++++
 3 files changed, 17 insertions(+)

diff --git a/CHANGES.rst b/CHANGES.rst
index f3aa7c8b3..3a9c5af4e 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -34,6 +34,12 @@ Release History
   (`#239 <https://github.com/nengo/nengo_spa/issues/239>`__,
   `#240 <https://github.com/nengo/nengo_spa/pull/240>`__)
 
+**Fixed**
+
+- Fixed an issue where the names of iteratively generated semantic pointers
+  could grow exponentially in length, by truncating them at 1 KB.
+  (`#244 <https://github.com/nengo/nengo_spa/issues/244>`__,
+  `#246 <https://github.com/nengo/nengo_spa/pull/246>`__)
 
 
 1.0.1 (December 14, 2019)
diff --git a/nengo_spa/semantic_pointer.py b/nengo_spa/semantic_pointer.py
index 0b548fce5..7b23390dc 100644
--- a/nengo_spa/semantic_pointer.py
+++ b/nengo_spa/semantic_pointer.py
@@ -42,6 +42,8 @@ class SemanticPointer(Fixed):
         Name of the Semantic Pointer.
     """
 
+    MAX_NAME = 1024
+
     def __init__(self, data, vocab=None, algebra=None, name=None):
         super(SemanticPointer, self).__init__(
             TAnyVocab if vocab is None else TVocabulary(vocab)
@@ -54,6 +56,9 @@ def __init__(self, data, vocab=None, algebra=None, name=None):
         self.v.setflags(write=False)
 
         self.vocab = vocab
+
+        if name is not None and len(name) > self.MAX_NAME:
+            name = "%s..." % (name[: self.MAX_NAME - 3])
         self.name = name
 
     def _get_algebra(cls, vocab, algebra):
diff --git a/nengo_spa/tests/test_semantic_pointer.py b/nengo_spa/tests/test_semantic_pointer.py
index 0b50b89cf..a32cb1e0b 100644
--- a/nengo_spa/tests/test_semantic_pointer.py
+++ b/nengo_spa/tests/test_semantic_pointer.py
@@ -323,3 +323,9 @@ def test_name():
 
     assert (a + unnamed).name is None
     assert (a * unnamed).name is None
+
+    # check that names that blow up exponentially in length are truncated
+    for i in range(10):
+        a += a * b
+    assert len(a.name) == a.MAX_NAME
+    assert a.name.endswith("...")