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Re: [PATCH 00/14] numparse module: systematically tighten up integer parsing

From
Junio C Hamano <gitster@pobox.com>
Date
Mar 24, 2015, 18:08 UTC
Message-ID
<xmqq1tke6zfv.fsf@gitster.dls.corp.google.com>
In-Reply-To
<5511A166.3090009@alum.mit.edu>
Michael Haggerty <mhagger@alum.mit.edu> writes:
Show 6 quoted lines
> Regarding specifically allowing/disallowing a leading '+': I saw a
> couple of callsites that explicitly check that the first character is a
> digit before calling strtol(). I assumed that is to disallow sign
> characters [1]. For example,
>
>     diff.c: optarg()

This one I know is from "if not a digit we know it is not a number"; it is not an attempt to say "we must forbid numbers to be spelled with '+'", but more about "we do not need it and this is easier to code without a full fledged str-to-num helper API" sloppiness.

>     builtin/apply.c: parse_num()

This parses "@@ -l,k +m,n @@@" after stripping the punctuation around the numbers, so this is a valid reason why you would want an optional feature "CANNOT_HAVE_SIGN" in the str-to-num parser and use it.

>     maybe date.c: match_multi_number()

The approxidate callers parse random garbage input and attempt to make best sense out of it, so they tend to try limitting the damage caused by incorrect guesses by insisting "we do not consider +0 to be zero" and such. So this is a valid reason why you would want an optional feature "CANNOT_HAVE_SIGN" in the str-to-num parser and use it.

Show 16 quoted lines
> I'm coming around to an alternate plan:
>
> Step 1: write a NUM_DEFAULT combination-of-options that gives the new
> functions behavior very like strtol()/strtoul() but without their insane
> features.
>
> Step 2: rewrite all callers to use that option (and usually endptr=NULL,
> meaning no trailing characters) unless it is manifestly clear that they
> are already trying to forbid some other features. This will already
> produce the largest benefit: avoiding overflows, missing error checking,
> etc.
>
> Steps 3 through ∞: as time allows, rewrite individual callsites to be
> stricter where appropriate.
>
> Hopefully steps 1 and 2 will not be too controversial.
All sounds sensible to me.
Previous: Michael Haggerty
Message 43 of 43 in “numparse module: systematically tighten up integer parsing”
  1. 00/14 numparse module: systematically tighten up integer parsingMichael Haggerty, Mar 17, 2015
  2. 01/14 numparse: new module for parsing integral numbersMichael Haggerty, Mar 17, 2015
  3. Eric SunshineMar 18, 2015
  4. Michael HaggertyMar 18, 2015
  5. Eric SunshineMar 20, 2015
  6. Junio C HamanoMar 20, 2015
  7. 02/14 cacheinfo_callback(): use convert_ui() when handling "--cacheinfo"Michael Haggerty, Mar 17, 2015
  8. 03/14 write_subdirectory(): use convert_ui() for parsing modeMichael Haggerty, Mar 17, 2015
  9. 04/14 handle_revision_opt(): use skip_prefix() in many placesMichael Haggerty, Mar 17, 2015
  10. 05/14 handle_revision_opt(): use convert_i() when handling "-<digit>"Michael Haggerty, Mar 17, 2015
  11. Junio C HamanoMar 19, 2015
  12. 06/14 strtoul_ui(), strtol_i(): remove functionsMichael Haggerty, Mar 17, 2015
  13. 07/14 handle_revision_opt(): use convert_ui() when handling "--abbrev="Michael Haggerty, Mar 17, 2015
  14. 08/14 builtin_diff(): detect errors when parsing --unified argumentMichael Haggerty, Mar 17, 2015
  15. 09/14 opt_arg(): val is always non-NULLMichael Haggerty, Mar 17, 2015
  16. 10/14 opt_arg(): use convert_i() in implementationMichael Haggerty, Mar 17, 2015
  17. 11/14 opt_arg(): report errors parsing option valuesMichael Haggerty, Mar 17, 2015
  18. 12/14 opt_arg(): simplify pointer handlingMichael Haggerty, Mar 17, 2015
  19. 13/14 diff_opt_parse(): use convert_i() when handling "-l<num>"Michael Haggerty, Mar 17, 2015
  20. 14/14 diff_opt_parse(): use convert_i() when handling --abbrev=<num>Michael Haggerty, Mar 17, 2015
  21. Junio C HamanoMar 19, 2015
  22. Junio C HamanoMar 17, 2015
  23. Michael HaggertyMar 17, 2015
  24. Junio C HamanoMar 19, 2015
  25. Duy NguyenMar 17, 2015
  26. Michael HaggertyMar 18, 2015
  27. Duy NguyenMar 18, 2015
  28. Jeff KingMar 18, 2015
  29. Michael HaggertyMar 18, 2015
  30. Jeff KingMar 19, 2015
  31. Junio C HamanoMar 19, 2015
  32. Junio C HamanoMar 19, 2015
  33. Michael HaggertyMar 24, 2015
  34. René ScharfeMar 24, 2015
  35. Michael HaggertyMar 25, 2015
  36. Junio C HamanoMar 25, 2015
  37. Michael HaggertyMar 24, 2015
  38. Junio C HamanoMar 19, 2015
  39. Michael HaggertyMar 24, 2015
  40. Junio C HamanoMar 24, 2015
  41. Junio C HamanoMar 24, 2015
  42. Michael HaggertyMar 24, 2015
  43. Junio C HamanoMar 24, 2015

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