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Code and IDLE should catch all compile errors. #69919

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Code and IDLE should catch all compile errors.#69919
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terryjreedy
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topic-IDLEtype-bugAn unexpected behavior, bug, or error

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@pppery
pppery
mannequin
opened on Nov 25, 2015
BPO 25733
Nosy @terryjreedy, @serhiy-storchaka, @pppery
Files
  • catch_all_syntax_errors.diff
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = 'https://github.com/terryjreedy'
closed_at = None
created_at = <Date 2015-11-25.14:26:38.301>
labels = ['expert-IDLE', 'type-bug', 'library', '3.9']
title = 'Code and IDLE should catch all compile errors.'
updated_at = <Date 2019-09-20.21:08:22.670>
user = 'https://github.com/pppery'

    bugs.python.org fields:

    activity = <Date 2019-09-20.21:08:22.670>
actor = 'terry.reedy'
assignee = 'terry.reedy'
closed = False
closed_date = None
closer = None
components = ['IDLE', 'Library (Lib)']
creation = <Date 2015-11-25.14:26:38.301>
creator = 'ppperry'
dependencies = []
files = ['43351']
hgrepos = []
issue_num = 25733
keywords = ['patch']
message_count = 10.0
messages = ['255358', '255478', '255483', '255486', '255487', '268171', '268177', '268288', '268295', '270406']
nosy_count = 3.0
nosy_names = ['terry.reedy', 'serhiy.storchaka', 'ppperry']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'test needed'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue25733'
versions = ['Python 3.9']

    Linked PRs

    Activity

    1. pppery commented on Nov 25, 2015

      @pppery
      ppperymannequin
      on Nov 25, 2015
      MannequinAuthor

      The following code:

      for a in range(26):
  for b in range(26):
   for c in range(26):
    for d in range(26):
     for e in range(26):
      for f in range(26):
       for g in range(26):
        for h in range(26):
         for i in range(26):
          for j in range(26):
           for k in range(26):
            for l in range(26):
             for m in range(26):
              for o in range(26):
               for p in range(26):
                for q in range(26):
                 for r in range(26):
                  for s in range(26):
                   for t in range(26):
                    for u in range(26):
                     for v in range(26):
                       for w in range(26):
                         pass

      fails to compile with SystemError: too many statically nested blocks when typed in the standard interpreter.

      When typed in an IDLE shell , pressing enter will not try to run the code, instead printing the SystemError to the console from which idle was started, instead of to the IDLE shell, which would be expected.

    2. pppery
      added
      interpreter-core(Objects, Python, Grammar, and Parser dirs)
      topic-IDLE
      type-bugAn unexpected behavior, bug, or error
      on Nov 25, 2015

    3. terryjreedy commented on Nov 27, 2015

      @terryjreedy
      terryjreedy
      on Nov 27, 2015
      Member

      I believe startup files are compiled in PyShell.py, line 649 (3.x)

              try:
            code = compile(source, filename, "exec")
        except (OverflowError, SyntaxError):

      and editor code is compiled in ScriptBinding.py, line 100

              try:
            # If successful, return the compiled code
            return compile(source, filename, "exec")
        except (SyntaxError, OverflowError, ValueError) as value:

      Adding SystemError to the tuple is trivial. I just need to test to verify. (Side note: I think the tuple should be the same for both. The reasons for entries other than SyntaxError should be documented. ValueError when compiling?)

      I believe that interactive input is forwarded to stdlib code.InteractiveInterpreter in PyShell.py, line 679

          try:
        # InteractiveInterpreter.runsource() calls its runcode() method,
        # which is overridden (see below)
        return InteractiveInterpreter.runsource(self, source, filename)

      The compile call and error catching is inside Lib/code.py, line 57.

              try:
            code = self.compile(source, filename, symbol)
        except (OverflowError, SyntaxError, ValueError):

      It should be fixed here.

    4. terryjreedy
      self-assigned this
      on Nov 27, 2015

    5. pppery commented on Nov 27, 2015

      @pppery
      ppperymannequin
      on Nov 27, 2015
      MannequinAuthor

      A similar problem occurs with the TypeError produced by attempting to compile a null byte.

    6. terryjreedy commented on Nov 27, 2015

      @terryjreedy
      terryjreedy
      on Nov 27, 2015
      Member

      How lovely ;-)

      >>> compile(chr(0), '', 'eval')  # 2.7, chr(0) is byte
Traceback (most recent call last):
  File "<pyshell#6>", line 1, in <module>
    compile(chr(0), '', 'eval')
TypeError: compile() expected string without null bytes

>>> compile(chr(0), '', 'eval')  # 3.4, chr(0) is unichar
Traceback (most recent call last):
  File "<pyshell#25>", line 1, in <module>
    compile(chr(0), '', 'eval')
ValueError: source code string cannot contain null bytes
>>> compile(bytes(1), '', 'eval')  # == 2.7 chr(0)
Traceback (most recent call last):
  File "<pyshell#27>", line 1, in <module>
    compile(bytes(1), '', 'eval')
ValueError: source code string cannot contain null bytes

      I almost think the long tuple should be replaced by Exception.

    7. pppery commented on Nov 27, 2015

      @pppery
      ppperymannequin
      on Nov 27, 2015
      MannequinAuthor

      Why does compile not support null bytes in the first place?

    8. terryjreedy commented on Jun 11, 2016

      @terryjreedy
      terryjreedy
      on Jun 11, 2016
      Member

      How to cause
      SyntaxError -- obvious
      NameError -- ?, already caught in code module
      OverflowError-- ?, already caught in code module
      SystemError - 22 nested for loops ('deeply nested blocks')
      TypeError -- chr(0), 2.7
      ValueError -- chr(0), 3.x; bytes(0), 2.7

    9. terryjreedy
      added
      stdlibStandard Library Python modules in the Lib/ directory
      and removed
      interpreter-core(Objects, Python, Grammar, and Parser dirs)
      on Jun 11, 2016
    10. terryjreedy
      changed the title [-]Idle does not handle non-standard compile errors[/-] [+]Code and IDLE should catch all compile errors.[/+] on Jun 11, 2016

    11. serhiy-storchaka commented on Jun 11, 2016

      @serhiy-storchaka
      serhiy-storchaka
      on Jun 11, 2016
      Member

      SystemError is serious bug. Please open separate issue for this.

      Why does compile not support null bytes in the first place?

      Due to implementation detail of CPython tokenizer. I uses NUL-terminated C strings.

      Yet one possible exception: MemoryError. I agree that the long tuple should be replaced by Exception.

    12. pppery commented on Jun 11, 2016

      @pppery
      ppperymannequin
      on Jun 11, 2016
      MannequinAuthor

      OverflowError is raised when one attempts to compile a string of 2**31 or more characters.

    13. 1 remaining item

    14. pppery commented on Jul 14, 2016

      @pppery
      ppperymannequin
      on Jul 14, 2016
      MannequinAuthor

      SystemError is serious bug. Please open separate issue for this.

      Done. I created bpo-27514

    15. terryjreedy
      added
      3.9 (EOL)end of life
      on Sep 20, 2019
    16. ezio-melotti
      transferred this issue fromon Apr 10, 2022
    17. terryjreedy
      added this to IDLE Issueson Jul 23, 2022
    18. terryjreedy
      removed
      3.9 (EOL)end of life
      stdlibStandard Library Python modules in the Lib/ directory
      on Jan 15, 2026

    19. serhiy-storchaka commented on Sep 15, 2026

      @serhiy-storchaka
      serhiy-storchaka
      on Sep 15, 2026
      Member

      Still relevant: compile() raises MemoryError or RecursionError for too deeply nested source, and a UnicodeEncodeError for surrogates; code, the REPL and IDLE catch only SyntaxError, OverflowError and ValueError, so IDLE's Shell gets stuck on such input. Two alternative fixes: #157585 makes them catch all exceptions (backportable), #157586 makes compile() raise SyntaxError in all these cases (main only).

    20. terryjreedy commented on Sep 15, 2026

      @terryjreedy
      terryjreedy
      on Sep 15, 2026
      Member

      I would like to have both applied.

    21. serhiy-storchaka
      added a commit that references this issue on Sep 23, 2026

      gh-69919: Catch all compile errors in the code module, pyrepl and IDLE (

      4bc392c
    22. terryjreedy
      added 2 commits that reference this issue on Sep 24, 2026

      [3.13] gh-69919: Catch all compile errors in the code module, pyrepl …

      0632698

      [3.14] gh-69919: Catch all compile errors in the code module, pyrepl …

      edc1034
    23. terryjreedy
      added a commit that references this issue on Oct 9, 2026

      [3.15] gh-69919: Catch all compile errors in the code module, pyrepl …

      e2b711c
    24. kevinprimeraquecreo-stack
      added this to Project_VKon Oct 18, 2026
    25. github-project-automation
      moved this to Todo in Project_VKon Oct 18, 2026
    26. kevinprimeraquecreo-stack
      added this to Project_VKon Oct 18, 2026
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