Reject negative input and partial parsing for unsigned argument types

[metsw24-max]

This patch fixes a parsing flaw in ValueReader where invalid numeric input could be silently accepted.

Issues addressed:

1. Negative values for unsigned types:
   Inputs such as "-1" were previously accepted and converted via
   wraparound (e.g., to UINT_MAX), which can bypass validation logic
   in downstream applications.

2. Partial numeric parsing:
   Inputs like "123abc" were partially parsed as 123 and accepted,
   ignoring trailing invalid characters.

Fix:

• Reject negative values for unsigned integral destinations
• Require full-string consumption during numeric parsing

[Taywee]

Feels a bit hacky, but that's the best you can really get when you're working with C++ iostreams.

Unfortunately, this does cause other unrelated tests to start failing:

taylor@project-zeus> make runtests
g++ test.cxx -o test.o -I. -std=c++11 -O0 -c -MMD -Wall -Wextra -Wno-unused-parameter -Werror -pedantic
g++ -o argstest test.o -std=c++11 -O0
./argstest

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
argstest is a Catch v2.13.7 host application.
Run with -? for options

-------------------------------------------------------------------------------
Argument flags work as expected, with clustering
-------------------------------------------------------------------------------
test.cxx:67
...............................................................................

test.cxx:67: FAILED:
due to unexpected exception with message:
  Argument 'BAZ' received invalid value type '7.555e2'

-------------------------------------------------------------------------------
Unified argument lists for match work
-------------------------------------------------------------------------------
test.cxx:93
...............................................................................

test.cxx:93: FAILED:
due to unexpected exception with message:
  Argument 'BAZ' received invalid value type '7.555e2'

-------------------------------------------------------------------------------
Argument flag lists work as expected
-------------------------------------------------------------------------------
test.cxx:142
...............................................................................

test.cxx:142: FAILED:
due to unexpected exception with message:
  Argument 'FOO' received invalid value type '7'

-------------------------------------------------------------------------------
Argument flag lists replace default values
-------------------------------------------------------------------------------
test.cxx:158
...............................................................................

test.cxx:158: FAILED:
due to unexpected exception with message:
  Argument 'FOO' received invalid value type '7'

-------------------------------------------------------------------------------
Positional lists work as expected
-------------------------------------------------------------------------------
test.cxx:166
...............................................................................

test.cxx:166: FAILED:
due to unexpected exception with message:
  Argument 'FOO' received invalid value type '7'

-------------------------------------------------------------------------------
Positional lists replace default values
-------------------------------------------------------------------------------
test.cxx:182
...............................................................................

test.cxx:182: FAILED:
due to unexpected exception with message:
  Argument 'FOO' received invalid value type '7'

-------------------------------------------------------------------------------
Positional arguments and positional argument lists work as expected
-------------------------------------------------------------------------------
test.cxx:200
...............................................................................

test.cxx:200: FAILED:
due to unexpected exception with message:
  Argument 'BAR' received invalid value type '0'

-------------------------------------------------------------------------------
The option terminator works as expected
-------------------------------------------------------------------------------
test.cxx:215
...............................................................................

test.cxx:215: FAILED:
due to unexpected exception with message:
  Argument 'BAR' received invalid value type '0'

-------------------------------------------------------------------------------
Custom types work
-------------------------------------------------------------------------------
test.cxx:355
...............................................................................

test.cxx:361: FAILED:
  {Unknown expression after the reported line}
due to unexpected exception with message:
  Argument 'INTS' received invalid value type '1,2'

-------------------------------------------------------------------------------
Custom parser prefixes (dd-style)
-------------------------------------------------------------------------------
test.cxx:373
...............................................................................

test.cxx:373: FAILED:
due to unexpected exception with message:
  Argument 'BYTES' received invalid value type '8'

-------------------------------------------------------------------------------
Custom parser prefixes (Some Windows styles)
-------------------------------------------------------------------------------
test.cxx:393
...............................................................................

test.cxx:393: FAILED:
due to unexpected exception with message:
  Argument 'BYTES' received invalid value type '8'

-------------------------------------------------------------------------------
Help menu can be grabbed as a string, passed into a stream, or by using the
overloaded stream operator
-------------------------------------------------------------------------------
test.cxx:413
...............................................................................

test.cxx:413: FAILED:
due to unexpected exception with message:
  Argument 'BYTES' received invalid value type '8'

-------------------------------------------------------------------------------
Required flags work as expected
-------------------------------------------------------------------------------
test.cxx:623
...............................................................................

test.cxx:623: FAILED:
due to unexpected exception with message:
  Argument 'foo' received invalid value type '42'

-------------------------------------------------------------------------------
Implicit values work as expected
-------------------------------------------------------------------------------
test.cxx:663
...............................................................................

test.cxx:671: FAILED:
  REQUIRE_NOTHROW( parser.ParseArgs(std::vector<std::string>{"-j4"}) )
due to unexpected exception with message:
  Argument 'parallel' received invalid value type '4'

-------------------------------------------------------------------------------
Nargs work as expected
-------------------------------------------------------------------------------
test.cxx:686
...............................................................................

test.cxx:697: FAILED:
  REQUIRE_NOTHROW( parser.ParseArgs(std::vector<std::string>{"-a", "1", "2"}) )
due to unexpected exception with message:
  Argument '' received invalid value type '1'

-------------------------------------------------------------------------------
ValueParser works as expected
-------------------------------------------------------------------------------
test.cxx:1197
...............................................................................

test.cxx:1217: FAILED:
  REQUIRE_NOTHROW( p.ParseArgs(std::vector<std::string>{"-i", " 12"}) )
due to unexpected exception with message:
  Argument 'name' received invalid value type ' 12'

-------------------------------------------------------------------------------
Noexcept mode works as expected
-------------------------------------------------------------------------------
test.cxx:1378
...............................................................................

test.cxx:1418: FAILED:
  REQUIRE( parser.GetError() == argstest::Error::None )
with expansion:
  2 == 0

-------------------------------------------------------------------------------
Required flags work as expected in noexcept mode
-------------------------------------------------------------------------------
test.cxx:1452
...............................................................................

test.cxx:1460: FAILED:
  REQUIRE( parser1.GetError() == argstest::Error::None )
with expansion:
  2 == 0

===============================================================================
test cases:  60 |  42 passed | 18 failed
assertions: 260 | 242 passed | 18 failed

[Taywee]

Tests are failing now and need to be fixed.

make runtests is usually the easiest way to run them.

[Taywee]

That looks good to me now, and tests now pass.

[Taywee]

Thank you for your contribution!