Activity

1. markshannon

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   3.13only security fixesonly security fixes

   3.14bugs and security fixesbugs and security fixes

   on Aug 8, 2024
2. markshannon commented on Aug 8, 2024

   

   markshannon

   on Aug 8, 2024

   MemberAuthor

   More actions

   Here's my hypothesis:

   This is an artifact of compiling while cond: body as:

   start:
       if not cond: goto end
       body
       if cond goto start
   end:
   

   and the assembler converting condition backwards jumps from if cond goto target to

       if not cond goto end
       goto target
   end:
   

   So we end up with:

   start:
       if not cond: goto end
       body
       if not cond goto end
       goto start
   end:
   

   When cond is True, the first branch jumps from cond to body, but the second branch jumps from cond to cond.

   Compiling while cond: body as:

   start:
       if not cond: goto end
       body
       goto start
   end:
   

   should fix this.
3. markshannon

   self-assigned this

   on Aug 12, 2024
4. markshannon

   added a commit that references this issue on Aug 13, 2024

   GH-122821: Simplify compilation of while statements to ensure consist…

   ...

   fe23f8e
5. blhsing

   added a commit that references this issue on Aug 22, 2024

   pythonGH-122821: Simplify compilation of while statements to ensure c…

   ...

   6eb343a
6. markshannon

   closed this as completedon May 6, 2025