Some people have mistaken Python bytecode as being stable and unchanging. In

reality it's simply an implementation detail for CPython. This point is now
clearly documented in both the docs for dis and the glossary.

Closes issue #7829. Thanks to Terry Reedy for some initial suggestions on
wording.

1 files changed, 8 insertions, 5 deletions

diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index 8363714..98744eb 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -57,11 +57,14 @@ Glossary
 
    bytecode
       Python source code is compiled into bytecode, the internal representation
-      of a Python program in the interpreter.  The bytecode is also cached in
-      ``.pyc`` and ``.pyo`` files so that executing the same file is faster the
-      second time (recompilation from source to bytecode can be avoided).  This
-      "intermediate language" is said to run on a :term:`virtual machine`
-      that executes the machine code corresponding to each bytecode.
+      of a Python program in the CPython interpreter.  The bytecode is also
+      cached in ``.pyc`` and ``.pyo`` files so that executing the same file is
+      faster the second time (recompilation from source to bytecode can be
+      avoided).  This "intermediate language" is said to run on a
+      :term:`virtual machine` that executes the machine code corresponding to
+      each bytecode. Do note that bytecodes are not expected to work between
+      different Python virtual machines, nor to be stable between Python
+      releases.
 
    class
       A template for creating user-defined objects. Class definitions