Merge branch 'blead' of ssh://perl5.git.perl.org/gitroot/perl into blead

* 'blead' of ssh://perl5.git.perl.org/gitroot/perl:
  move version details to version::Internals and other clean up
  document version::is_strict/is_lax
  Document usage of version regexps
  Export and document is_lax and is_strict functions
  note that delete/exists ARRAY_ELEM should be avoided
  Don't try to calculate a time over the conservative failure boundary.

11 files changed, 445 insertions, 293 deletions

diff --git a/MANIFEST b/MANIFEST
index b065311f1d..730a1ddfa7 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -4488,6 +4488,7 @@ t/op/threads.t			Misc. tests for perl features with threads
 t/op/tiearray.t			See if tie for arrays works
 t/op/tiehandle.t		See if tie for handles works
 t/op/tie.t			See if tie/untie functions work
+t/op/time_loop.t		Test that very large values don't hang gmtime and localtime.
 t/op/time.t			See if time functions work
 t/op/tr.t			See if tr works
 t/op/undef.t			See if undef works
diff --git a/lib/Time/gmtime.t b/lib/Time/gmtime.t
index 9c77f81570..b7840965a2 100644
--- a/lib/Time/gmtime.t
+++ b/lib/Time/gmtime.t
@@ -9,10 +9,10 @@ BEGIN {
 
 my(@times, @methods);
 BEGIN {
-    @times   = (-2**62, -2**50, -2**33, -2**31-1, -1, 0, 1, 2**31-1, 2**33, 2**50, 2**62, time);
+    @times   = (-2**55, -2**50, -2**33, -2**31-1, -1, 0, 1, 2**31-1, 2**33, 2**50, 2**55, time);
     @methods = qw(sec min hour mday mon year wday yday isdst);
 
-    plan tests => (@times * @methods) + 1;
+    plan tests => (@times * (@methods + 1)) + 1;
 
     use_ok Time::gmtime;
 }
@@ -21,6 +21,7 @@ for my $time (@times) {
     my $gmtime = gmtime $time;          # This is the OO gmtime.
     my @gmtime = CORE::gmtime $time;    # This is the gmtime function
 
+    is @gmtime, 9, "gmtime($time)";
     for my $method (@methods) {
         is $gmtime->$method, shift @gmtime, "gmtime($time)->$method";
     }
diff --git a/lib/Time/localtime.t b/lib/Time/localtime.t
index f300343ff8..0b020fcf7b 100644
--- a/lib/Time/localtime.t
+++ b/lib/Time/localtime.t
@@ -9,10 +9,10 @@ BEGIN {
 
 my(@times, @methods);
 BEGIN {
-    @times   = (-2**62, -2**50, -2**33, -2**31-1, -1, 0, 1, 2**31-1, 2**33, 2**50, 2**62, time);
+    @times   = (-2**55, -2**50, -2**33, -2**31-1, -1, 0, 1, 2**31-1, 2**33, 2**50, 2**55, time);
     @methods = qw(sec min hour mday mon year wday yday isdst);
 
-    plan tests => (@times * @methods) + 1;
+    plan tests => (@times * (@methods + 1)) + 1;
 
     use_ok Time::localtime;
 }
@@ -21,6 +21,7 @@ for my $time (@times) {
     my $localtime = localtime $time;          # This is the OO localtime.
     my @localtime = CORE::localtime $time;    # This is the localtime function
 
+    is @localtime, 9, "localtime($time)";
     for my $method (@methods) {
         is $localtime->$method, shift @localtime, "localtime($time)->$method";
     }
diff --git a/lib/version.pm b/lib/version.pm
index 424463d035..6b44e24cd5 100644
--- a/lib/version.pm
+++ b/lib/version.pm
@@ -141,19 +141,31 @@ sub import {
     my $callpkg = caller();
     
     if (exists($args{declare})) {
-	*{$callpkg."::declare"} = 
+	*{$callpkg.'::declare'} = 
 	    sub {return $class->declare(shift) }
 	  unless defined(&{$callpkg.'::declare'});
     }
 
     if (exists($args{qv})) {
-	*{$callpkg."::qv"} =
+	*{$callpkg.'::qv'} =
 	    sub {return $class->qv(shift) }
-	  unless defined(&{"$callpkg\::qv"});
+	  unless defined(&{$callpkg.'::qv'});
     }
 
     if (exists($args{'VERSION'})) {
-	*{$callpkg."::VERSION"} = \&version::_VERSION;
+	*{$callpkg.'::VERSION'} = \&version::_VERSION;
+    }
+
+    if (exists($args{'is_strict'})) {
+	*{$callpkg.'::is_strict'} = 
+	    sub {return $class->is_strict(shift)}
+	  unless defined(&{$callpkg.'::is_strict'});
+    }
+
+    if (exists($args{'is_lax'})) {
+	*{$callpkg.'::is_lax'} = 
+	    sub {return $class->is_lax(shift)}
+	  unless defined(&{$callpkg.'::is_lax'});
     }
 }
 
diff --git a/lib/version.pod b/lib/version.pod
index 090b5969ee..a8cded81b0 100644
--- a/lib/version.pod
+++ b/lib/version.pod
@@ -17,6 +17,7 @@ version - Perl extension for Version Objects
 
   # Declaring an old-style decimal $VERSION (use quotes!)
 
+  our $VERSION = "1.0203";                                     # recommended
   use version 0.77; our $VERSION = version->parse("1.0203");   # formal
   use version 0.77; our $VERSION = version->parse("1.02_03");  # alpha
 
@@ -37,7 +38,7 @@ objects for older version of Perl and provides the version object API for all
 versions of Perl.  All previous releases before 0.74 are deprecated and should
 not be used due to incompatible API changes.  Version 0.77 introduces the new
 'parse' and 'declare' methods to standardize usage.  You are strongly urged to
-set 0.77 as a minimum in your code, e.g. 
+set 0.77 as a minimum in your code, e.g.
 
   use version 0.77; # even for Perl v.5.10.0
 
@@ -51,37 +52,36 @@ different styles of versions in use:
 =item Decimal Versions
 
 The classic floating-point number $VERSION.  The advantage to this style is
-that you don't need to do anything special, just type a number (without
-quotes) into your source file.
+that you don't need to do anything special, just type a number into your
+source file.  Quoting is recommended, as it ensures that trailing zeroes
+("1.50") are preserved in any warnings or other output.
 
 =item Dotted Decimal Versions
 
 The more modern form of version assignment, with 3 (or potentially more)
 integers seperated by decimal points (e.g. v1.2.3).  This is the form that
-Perl itself has used since 5.6.0 was released.  The leading "v" is now 
+Perl itself has used since 5.6.0 was released.  The leading "v" is now
 strongly recommended for clarity, and will throw a warning in a future
 release if omitted.
 
 =back
 
-See L<VERSION OBJECT DETAILS> for further information.
-
 =head1 DECLARING VERSIONS
 
 If you have a module that uses a decimal $VERSION (floating point), and you
 do not intend to ever change that, this module is not for you.  There is
 nothing that version.pm gains you over a simple $VERSION assignment:
 
-  our $VERSION = 1.02;
+  our $VERSION = "1.02";
 
-Since Perl v5.10.0 includes the version.pm comparison logic anyways, 
+Since Perl v5.10.0 includes the version.pm comparison logic anyways,
 you don't need to do anything at all.
 
 =head2 How to convert a module from decimal to dotted-decimal
 
 If you have used a decimal $VERSION in the past and wish to switch to a
 dotted-decimal $VERSION, then you need to make a one-time conversion to
-the new format. 
+the new format.
 
 B<Important Note>: you must ensure that your new $VERSION is numerically
 greater than your current decimal $VERSION; this is not always obvious. First,
@@ -128,14 +128,14 @@ If you really insist on using version.pm with an ordinary decimal version,
 use C<parse()> instead of declare.  See the L<PARSING AND COMPARING VERSIONS>
 for details.
 
-See also L<VERSION OBJECT DETAILS> for more on version number conversion,
+See also L<version::Internals> for more on version number conversion,
 quoting, calculated version numbers and declaring developer or "alpha" version
 numbers.
 
 =head1 PARSING AND COMPARING VERSIONS
 
 If you need to compare version numbers, but can't be sure whether they are
-expressed as numbers, strings, v-strings or version objects,  then you can
+expressed as numbers, strings, v-strings or version objects,  then you should
 use version.pm to parse them all into objects for comparison.
 
 =head2 How to C<parse()> a version
@@ -169,7 +169,44 @@ Some examples:
   "1.2.3"     v1.2.3
   "v1.2.3"    v1.2.3
 
-See L<VERSION OBJECT DETAILS> for more on version number conversion.
+See L<version::Internals> for more on version number conversion.
+
+=head2 How to check for a legal version string
+
+If you do not want to actually create a full blown version object, but
+would still like to verify that a given string meets the criteria to
+be parsed as a version, there are two helper functions that can be
+employed directly:
+
+=over 4
+
+=item C<is_lax()>
+
+The lax criteria corresponds to what is currently allowed by the
+version parser.  All of the following formats are acceptable
+for dotted-decimal formats strings:
+
+    v1.2
+    1.2345.6
+    v1.23_4
+    1.2345
+    1.2345_01
+
+=item C<is_strict()>
+
+If you want to limit youself to a much more narrow definition of what
+a version string constitutes, C<is_strict()> is limited to version
+strings like the following list:
+
+    v1.234.5
+    2.3456
+
+=back
+
+See L<version::Internals> for details of the regular expressions
+that define the legal version string forms, as well as how to use
+those regular expressions in your own code if C<is_lax()> and
+C<is_strict()> are not sufficient for your needs.
 
 =head2 How to compare version objects
 
@@ -192,110 +229,13 @@ Always comparing to a version object will help avoid surprises:
 
   $bool = $v1 < version->parse("v0.96.0"); # TRUE
 
-=head1 VERSION OBJECT DETAILS
-
-=head2 Equivalence between Decimal and Dotted-Decimal Versions
-
-When Perl 5.6.0 was released, the decision was made to provide a
-transformation between the old-style decimal versions and new-style
-dotted-decimal versions:
-
-  5.6.0    == 5.006000
-  5.005_04 == 5.5.40
-
-The floating point number is taken and split first on the single decimal
-place, then each group of three digits to the right of the decimal makes up
-the next digit, and so on until the number of significant digits is exhausted,
-B<plus> enough trailing zeros to reach the next multiple of three.
-
-This was the method that version.pm adopted as well.  Some examples may be
-helpful:
-
-                            equivalent
-  decimal    zero-padded    dotted-decimal
-  -------    -----------    --------------
-  1.2        1.200          v1.200.0
-  1.02       1.020          v1.20.0
-  1.002      1.002          v1.2.0
-  1.0023     1.002300       v1.2.300
-  1.00203    1.002030       v1.2.30
-  1.002003   1.002003       v1.2.3
-
-=head2 Quoting rules
-
-Because of the nature of the Perl parsing and tokenizing routines,
-certain initialization values B<must> be quoted in order to correctly
-parse as the intended version, especially when using the L<declare> or
-L<qv> methods.  While you do not have to quote decimal numbers when
-creating version objects, it is always safe to quote B<all> initial values
-when using version.pm methods, as this will ensure that what you type is
-what is used.
+Note that "alpha" version objects (where the version string contains
+a trailing underscore segment) compare as less than the equivalent
+version without an underscore:
 
-Additionally, if you quote your initializer, then the quoted value that goes
-B<in> will be be exactly what comes B<out> when your $VERSION is printed
-(stringified).  If you do not quote your value, Perl's normal numeric handling
-comes into play and you may not get back what you were expecting.
+  $bool = version->parse("1.23_45") < version->parse("1.2345"); # TRUE
 
-If you use a mathematic formula that resolves to a floating point number,
-you are dependent on Perl's conversion routines to yield the version you
-expect.  You are pretty safe by dividing by a power of 10, for example,
-but other operations are not likely to be what you intend.  For example:
-
-  $VERSION = version->new((qw$Revision: 1.4)[1]/10);
-  print $VERSION;          # yields 0.14
-  $V2 = version->new(100/9); # Integer overflow in decimal number
-  print $V2;               # yields something like 11.111.111.100
-
-Perl 5.8.1 and beyond are able to automatically quote v-strings but
-that is not possible in earlier versions of Perl.  In other words:
-
-  $version = version->new("v2.5.4");  # legal in all versions of Perl
-  $newvers = version->new(v2.5.4);    # legal only in Perl >= 5.8.1
-
-=head2 What about v-strings?
-
-There are two ways to enter v-strings: a bare number with two or more
-decimal points, or a bare number with one or more decimal points and a 
-leading 'v' character (also bare).  For example:
-
-  $vs1 = 1.2.3; # encoded as \1\2\3
-  $vs2 = v1.2;  # encoded as \1\2 
-
-However, the use of bare v-strings to initialize version objects is
-B<strongly> discouraged in all circumstances.  Also, bare
-v-strings are not completely supported in any version of Perl prior to
-5.8.1.
-
-If you insist on using bare v-strings with Perl > 5.6.0, be aware of the 
-following limitations:
-
-1) For Perl releases 5.6.0 through 5.8.0, the v-string code merely guesses, 
-based on some characteristics of v-strings.  You B<must> use a three part
-version, e.g. 1.2.3 or v1.2.3 in order for this heuristic to be successful.
-
-2) For Perl releases 5.8.1 and later, v-strings have changed in the Perl
-core to be magical, which means that the version.pm code can automatically
-determine whether the v-string encoding was used.
-
-3) In all cases, a version created using v-strings will have a stringified
-form that has a leading 'v' character, for the simple reason that sometimes
-it is impossible to tell whether one was present initially.
-
-=head2 Alpha versions
-
-For module authors using CPAN, the convention has been to note unstable
-releases with an underscore in the version string. (See L<CPAN>.)  version.pm
-follows this convention and alpha releases will test as being newer than the
-more recent stable release, and less than the next stable release.  For
-dotted-decimal versions, only the last element may be separated by an
-underscore:
-
-  # Declaring
-  use version 0.77; our $VERSION = version->declare("v1.2_3");
-
-  # Parsing
-  $v1 = version->parse("v1.2_3");
-  $v1 = version->parse("1.002_003");
+See L<version::Internals> for more details on "alpha" versions.
 
 =head1 OBJECT METHODS
 
@@ -352,13 +292,29 @@ to your namespace, use this form:
 
   use version 0.77 ();
 
+=head2 is_lax()
+
+(Not exported by default)
+
+This function takes a scalar argument and returns a boolean value indicating
+whether the argument meets the "lax" rules for a version number.  Leading and
+trailing spaces are not allowed.
+
+=head2 is_strict()
+
+(Not exported by default)
+
+This function takes a scalar argument and returns a boolean value indicating
+whether the argument meets the "strict" rules for a version number.  Leading
+and trailing spaces are not allowed.
+
 =head1 AUTHOR
 
 John Peacock E<lt>jpeacock@cpan.orgE<gt>
 
 =head1 SEE ALSO
 
-L<version::Internal>.
+L<version::Internals>.
 
 L<perl>.
 
diff --git a/lib/version/Internals.pod b/lib/version/Internals.pod
index 597b46555e..cb179c04fd 100644
--- a/lib/version/Internals.pod
+++ b/lib/version/Internals.pod
@@ -1,20 +1,20 @@
 =head1 NAME
 
-version::Internal - Perl extension for Version Objects
+version::Internals - Perl extension for Version Objects
 
 =head1 DESCRIPTION
 
 Overloaded version objects for all modern versions of Perl.  This documents
 the internal data representation and underlying code for version.pm.  See
 L<version.pod> for daily usage.  This document is only useful for users
-writing a subclass of version.pm or interested in the gory details.
+interested in the gory details.
 
-=head1 What IS a version
+=head1 WHAT IS A VERSION?
 
 For the purposes of this module, a version "number" is a sequence of
-positive integer values separated by one or more decimal points and 
-optionally a single underscore.  This corresponds to what Perl itself 
-uses for a version, as well as extending the "version as number" that 
+positive integer values separated by one or more decimal points and
+optionally a single underscore.  This corresponds to what Perl itself
+uses for a version, as well as extending the "version as number" that
 is discussed in the various editions of the Camel book.
 
 There are actually two distinct kinds of version objects:
@@ -25,7 +25,7 @@ There are actually two distinct kinds of version objects:
 
 Any version which "looks like a number", see L<Decimal Versions>.  This
 also includes versions with a single decimal point and a single embedded
-underscore, see L<Decimal Alpha Versions>, even though these must be quoted
+underscore, see L<Alpha Versions>, even though these must be quoted
 to preserve the underscore formatting.
 
 =item Dotted-Decimal Versions
@@ -39,7 +39,7 @@ A leading 'v' character is now required and will warn if it missing.
 =back
 
 Both of these methods will produce similar version objects, in that
-the default stringification will yield the version L<Normal Form> only 
+the default stringification will yield the version L<Normal Form> only
 if required:
 
   $v  = version->new(1.002);     # 1.002, but compares like 1.2.0
@@ -63,7 +63,7 @@ to the right of the decimal place) that contains less than three digits
 will have trailing zeros added to make up the difference, but only for
 purposes of comparison with other version objects.  For example:
 
-                                   # Prints     Equivalent to  
+                                   # Prints     Equivalent to
   $v = version->new(      1.2);    # 1.2        v1.200.0
   $v = version->new(     1.02);    # 1.02       v1.20.0
   $v = version->new(    1.002);    # 1.002      v1.2.0
@@ -71,14 +71,14 @@ purposes of comparison with other version objects.  For example:
   $v = version->new(  1.00203);    # 1.00203    v1.2.30
   $v = version->new( 1.002003);    # 1.002003   v1.2.3
 
-All of the preceding examples are true whether or not the input value is 
-quoted.  The important feature is that the input value contains only a 
-single decimal.  See also L<version/Alpha Versions> for how to handle
+All of the preceding examples are true whether or not the input value is
+quoted.  The important feature is that the input value contains only a
+single decimal.  See also L<Alpha Versions>.
 
-IMPORTANT NOTE: As shown above, if your Decimal version contains more 
-than 3 significant digits after the decimal place, it will be split on 
-each multiple of 3, so 1.0003 is equivalent to v1.0.300, due to the need 
-to remain compatible with Perl's own 5.005_03 == 5.5.30 interpretation.  
+IMPORTANT NOTE: As shown above, if your Decimal version contains more
+than 3 significant digits after the decimal place, it will be split on
+each multiple of 3, so 1.0003 is equivalent to v1.0.300, due to the need
+to remain compatible with Perl's own 5.005_03 == 5.5.30 interpretation.
 Any trailing zeros are ignored for mathematical comparison purposes.
 
 =head2 Dotted-Decimal Versions
@@ -86,7 +86,7 @@ Any trailing zeros are ignored for mathematical comparison purposes.
 These are the newest form of versions, and correspond to Perl's own
 version style beginning with 5.6.0.  Starting with Perl 5.10.0,
 and most likely Perl 6, this is likely to be the preferred form.  This
-method normally requires that the input parameter be quoted, although 
+method normally requires that the input parameter be quoted, although
 Perl's after 5.8.1 can use v-strings as a special form of quoting, but
 this is highly discouraged.
 
@@ -105,39 +105,208 @@ to specify a version, whereas Decimal Versions enforce a certain
 uniformity.  See also L<New Operator> for an additional method of
 initializing version objects.
 
-Just like L<Decimal Versions>, Dotted-Decimal Versions can be used as 
-L<version/Alpha Versions>.
+Just like L<Decimal Versions>, Dotted-Decimal Versions can be used as
+L<Alpha Versions>.
 
-=head2 Decimal Alpha Versions
+=head2 Alpha Versions
 
-The one time that a Decimal version must be quoted is when a alpha form is
-used with an otherwise Decimal version (i.e. a single decimal point).  This
-is commonly used for CPAN releases, where CPAN or CPANPLUS will ignore alpha
-versions for automatic updating purposes.  Since some developers have used
-only two significant decimal places for their non-alpha releases, the
-version object will automatically take that into account if the initializer
-is quoted.  For example Module::Example was released to CPAN with the
-following sequence of $VERSION's:
+For module authors using CPAN, the convention has been to note unstable
+releases with an underscore in the version string. (See L<CPAN>.)  version.pm
+follows this convention and alpha releases will test as being newer than the
+more recent stable release, and less than the next stable release.  Only the
+last element may be separated by an underscore:
 
-  # $VERSION    Stringified
-  0.01          0.01
-  0.02          0.02
-  0.02_01       0.02_01
-  0.02_02       0.02_02
-  0.03          0.03
-  etc.
+  # Declaring
+  use version 0.77; our $VERSION = version->declare("v1.2_3");
 
-The stringified form of Decimal versions will always be the same string
-that was used to initialize the version object.
+  # Parsing
+  $v1 = version->parse("v1.2_3");
+  $v1 = version->parse("1.002_003");
 
-=head1 High level design
+Note that you B<must> quote the version when writing an alpha Decimal version.
+The stringified form of Decimal versions will always be the same string that
+was used to initialize the version object.
 
-=head2 version objects
+=head2 Regular Expressions for Version Parsing
 
-version.pm provides an overloaded version object that is designed to both 
+A formalized definition of the legal forms for version strings is
+included in the main F<version.pm> file.  Primitives are included for
+common elements, although they are scoped to the file so they are useful
+for reference purposes only.  There are two publicly accessible scalars
+that can be used in other code (not exported):
+
+=over 4
+
+=item C<$version::LAX>
+
+This regexp covers all of the legal forms allowed under the current
+version string parser.  This is not to say that all of these forms
+are recommended, and some of them can only be used when quoted.
+
+For dotted decimals:
+
+    v1.2
+    1.2345.6
+    v1.23_4
+
+The leading 'v' is optional if two or more decimals appear.  If only
+a single decimal is included, then the leading 'v' is required to
+trigger the dotted-decimal parsing.  A leading zero is permitted,
+though not recommended except when quoted, because of the risk that
+Perl will treat the number as octal.  A trailing underscore plus one
+or more digits denotes an alpha or development release (and must be
+quoted to be parsed properly).
+
+For decimal versions:
+
+    1
+    1.2345
+    1.2345_01
+
+an integer portion, an optional decimal point, and optionally one or
+more digits to the right of the decimal are all required.  A trailing
+underscore is permitted and a leading zero is permitted.  Just like
+the lax dotted-decimal version, quoting the values is required for
+alpha/development forms to be parsed correctly.
+
+=item C<$version::STRICT>
+
+This regexp covers a much more limited set of formats and constitutes
+the best practices for initializing version objects.  Whether you choose
+to employ decimal or dotted-decimal for is a personal preference however.
+
+=over 4
+
+=item v1.234.5
+
+For dotted-decimal versions, a leading 'v' is required, with three or
+more sub-versions of no more than three digits.  A leading 0 (zero)
+before the first sub-version (in the above example, '1') is also
+prohibited.
+
+=item 2.3456
+
+For decimal versions, an integer portion (no leading 0), a decimal point,
+and one or more digits to the right of the decimal are all required.
+
+=back
+
+=back
+
+Both of the provided scalars are already compiled as regular expressions
+and do not contain either anchors or implicit groupings, so they can be
+included in your own regular expressions freely.  For example, consider
+the following code:
+
+	($pkg, $ver) =~ /
+		^[ \t]*
+		use [ \t]+($PKGNAME)
+		(?:[ \t]+($version::STRICT))?
+		[ \t]*;
+	/x;
+
+This would match a line of the form:
+
+	use Foo::Bar::Baz v1.2.3;	# legal only in Perl 5.8.1+
+
+where C<$PKGNAME> is another regular expression that defines the legal
+forms for package names.
+
+=head1 IMPLEMENTATION DETAILS
+
+=head2 Equivalence between Decimal and Dotted-Decimal Versions
+
+When Perl 5.6.0 was released, the decision was made to provide a
+transformation between the old-style decimal versions and new-style
+dotted-decimal versions:
+
+  5.6.0    == 5.006000
+  5.005_04 == 5.5.40
+
+The floating point number is taken and split first on the single decimal
+place, then each group of three digits to the right of the decimal makes up
+the next digit, and so on until the number of significant digits is exhausted,
+B<plus> enough trailing zeros to reach the next multiple of three.
+
+This was the method that version.pm adopted as well.  Some examples may be
+helpful:
+
+                            equivalent
+  decimal    zero-padded    dotted-decimal
+  -------    -----------    --------------
+  1.2        1.200          v1.200.0
+  1.02       1.020          v1.20.0
+  1.002      1.002          v1.2.0
+  1.0023     1.002300       v1.2.300
+  1.00203    1.002030       v1.2.30
+  1.002003   1.002003       v1.2.3
+
+=head2 Quoting Rules
+
+Because of the nature of the Perl parsing and tokenizing routines,
+certain initialization values B<must> be quoted in order to correctly
+parse as the intended version, especially when using the L<declare> or
+L<qv> methods.  While you do not have to quote decimal numbers when
+creating version objects, it is always safe to quote B<all> initial values
+when using version.pm methods, as this will ensure that what you type is
+what is used.
+
+Additionally, if you quote your initializer, then the quoted value that goes
+B<in> will be be exactly what comes B<out> when your $VERSION is printed
+(stringified).  If you do not quote your value, Perl's normal numeric handling
+comes into play and you may not get back what you were expecting.
+
+If you use a mathematic formula that resolves to a floating point number,
+you are dependent on Perl's conversion routines to yield the version you
+expect.  You are pretty safe by dividing by a power of 10, for example,
+but other operations are not likely to be what you intend.  For example:
+
+  $VERSION = version->new((qw$Revision: 1.4)[1]/10);
+  print $VERSION;          # yields 0.14
+  $V2 = version->new(100/9); # Integer overflow in decimal number
+  print $V2;               # yields something like 11.111.111.100
+
+Perl 5.8.1 and beyond are able to automatically quote v-strings but
+that is not possible in earlier versions of Perl.  In other words:
+
+  $version = version->new("v2.5.4");  # legal in all versions of Perl
+  $newvers = version->new(v2.5.4);    # legal only in Perl >= 5.8.1
+
+=head2 What about v-strings?
+
+There are two ways to enter v-strings: a bare number with two or more
+decimal points, or a bare number with one or more decimal points and a
+leading 'v' character (also bare).  For example:
+
+  $vs1 = 1.2.3; # encoded as \1\2\3
+  $vs2 = v1.2;  # encoded as \1\2
+
+However, the use of bare v-strings to initialize version objects is
+B<strongly> discouraged in all circumstances.  Also, bare
+v-strings are not completely supported in any version of Perl prior to
+5.8.1.
+
+If you insist on using bare v-strings with Perl > 5.6.0, be aware of the
+following limitations:
+
+1) For Perl releases 5.6.0 through 5.8.0, the v-string code merely guesses,
+based on some characteristics of v-strings.  You B<must> use a three part
+version, e.g. 1.2.3 or v1.2.3 in order for this heuristic to be successful.
+
+2) For Perl releases 5.8.1 and later, v-strings have changed in the Perl
+core to be magical, which means that the version.pm code can automatically
+determine whether the v-string encoding was used.
+
+3) In all cases, a version created using v-strings will have a stringified
+form that has a leading 'v' character, for the simple reason that sometimes
+it is impossible to tell whether one was present initially.
+
+=head2 Version Object Internals
+
+version.pm provides an overloaded version object that is designed to both
 encapsulate the author's intended $VERSION assignment as well as make it
 completely natural to use those objects as if they were numbers (e.g. for
-comparisons).  To do this, a version object contains both the original 
+comparisons).  To do this, a version object contains both the original
 representation as typed by the author, as well as a parsed representation
 to ease comparisons.  Version objects employ L<overload> methods to
 simplify code that needs to compare, print, etc the objects.
@@ -232,7 +401,7 @@ The replacement UNIVERSAL::VERSION, when used as a function, like this:
 will also exclusively return the stringified form.  See L<Stringification>
 for more details.
 
-=head1 Usage question
+=head1 USAGE DETAILS
 
 =head2 Using modules that use version.pm
 
@@ -281,21 +450,15 @@ version.
 
 =head2 Object Methods
 
-Overloading has been used with version objects to provide a natural
-interface for their use.  All mathematical operations are forbidden,
-since they don't make any sense for base version objects.  Consequently,
-there is no overloaded numification available.  If you want to use a
-version object in a Decimal context for some reason, see the L<numify>
-object method.
-
 =over 4
 
-=item New Operator
+=item new()
 
-Like all OO interfaces, the new() operator is used to initialize
-version objects.  One way to increment versions when programming is to
-use the CVS variable $Revision, which is automatically incremented by
-CVS every time the file is committed to the repository.
+Like many OO interfaces, the new() method is used to initialize version
+objects.  If two arguments are passed to C<new()>, the B<second> one will be
+used as if it were prefixed with "v".  This is to support historical use of the
+C<qw> operator with the CVS variable $Revision, which is automatically
+incremented by CVS every time the file is committed to the repository.
 
 In order to facilitate this feature, the following
 code can be employed:
@@ -347,7 +510,7 @@ point interpretation.  For example:
   $v1 = qv(1.2);         # v1.2.0
   $v2 = qv("1.2");       # also v1.2.0
 
-As you can see, either a bare number or a quoted string can usually 
+As you can see, either a bare number or a quoted string can usually
 be used interchangably, except in the case of a trailing zero, which
 must be quoted to be converted properly.  For this reason, it is strongly
 recommended that all initializers to qv() be quoted strings instead of
@@ -363,16 +526,15 @@ or just require version, like this:
   require version;
 
 Both methods will prevent the import() method from firing and exporting the
-C<qv()> sub.  This is true of subclasses of version as well, see
-L<SUBCLASSING> for details.
+C<qv()> sub.
 
 =back
 
 For the subsequent examples, the following three objects will be used:
 
-  $ver   = version->new("1.2.3.4"); # see "Quoting" below
-  $alpha = version->new("1.2.3_4"); # see "<version/Alpha versions" below
-  $nver  = version->new(1.002);     # see "Decimal Versions" above
+  $ver   = version->new("1.2.3.4"); # see "Quoting Rules"
+  $alpha = version->new("1.2.3_4"); # see "Alpha Versions"
+  $nver  = version->new(1.002);     # see "Decimal Versions"
 
 =over 4
 
@@ -387,9 +549,9 @@ a normalized or reduced form (no extraneous zeros), and with a leading 'v':
   print $ver->stringify;      # ditto
   print $ver;                 # ditto
   print $nver->normal;        # prints as v1.2.0
-  print $nver->stringify;     # prints as 1.002, see "Stringification" 
+  print $nver->stringify;     # prints as 1.002, see "Stringification"
 
-In order to preserve the meaning of the processed version, the 
+In order to preserve the meaning of the processed version, the
 normalized representation will always contain at least three sub terms.
 In other words, the following is guaranteed to always be true:
 
@@ -404,7 +566,7 @@ In other words, the following is guaranteed to always be true:
 =item Numification
 
 Although all mathematical operations on version objects are forbidden
-by default, it is possible to retrieve a number which corresponds 
+by default, it is possible to retrieve a number which corresponds
 to the version object through the use of the $obj->numify
 method.  For formatting purposes, when displaying a number which
 corresponds a version object, all sub versions are assumed to have
@@ -437,7 +599,7 @@ For example:
   version->new("v1.2")     v1.2
   qv("1.2.3")               1.2.3
   qv("v1.3.5")             v1.3.5
-  qv("1.2")                v1.2   ### exceptional case 
+  qv("1.2")                v1.2   ### exceptional case
 
 See also L<UNIVERSAL::VERSION>, as this also returns the stringified form
 when used as a class method.
@@ -492,7 +654,7 @@ For example, the following relations hold:
 
 It is probably best to chose either the Decimal notation or the string
 notation and stick with it, to reduce confusion.  Perl6 version objects
-B<may> only support Decimal comparisons.  See also L<Quoting>.
+B<may> only support Decimal comparisons.  See also L<Quoting Rules>.
 
 WARNING: Comparing version with unequal numbers of decimal points (whether
 explicitly or implicitly initialized), may yield unexpected results at
@@ -516,7 +678,7 @@ has been initialized, you can simply test it directly:
   $vobj = version->new($something);
   if ( $vobj )   # true only if $something was non-blank
 
-You can also test whether a version object is an L<version/Alpha version>, for
+You can also test whether a version object is an L<Alpha Version>, for
 example to prevent the use of some feature not present in the main
 release:
 
@@ -526,76 +688,6 @@ release:
 
 =back
 
-=head2 Quoting
-
-Because of the nature of the Perl parsing and tokenizing routines,
-certain initialization values B<must> be quoted in order to correctly
-parse as the intended version, especially when using the L<qv>() operator.
-In all cases, a floating point number passed to version->new() will be
-identically converted whether or not the value itself is quoted.  This is
-not true for L<qv>(), however, when trailing zeros would be stripped on
-an unquoted input, which would result in a very different version object.
-
-In addition, in order to be compatible with earlier Perl version styles,
-any use of versions of the form 5.006001 will be translated as v5.6.1.  
-In other words, a version with a single decimal point will be parsed as
-implicitly having three digits between subversions, but only for internal
-comparison purposes.
-
-The complicating factor is that in bare numbers (i.e. unquoted), the
-underscore is a legal Decimal character and is automatically stripped
-by the Perl tokenizer before the version code is called.  However, if
-a number containing one or more decimals and an underscore is quoted, i.e.
-not bare, that is considered an L<version/Alpha version> and the underscore is
-significant.
-
-If you use a mathematic formula that resolves to a floating point number,
-you are dependent on Perl's conversion routines to yield the version you
-expect.  You are pretty safe by dividing by a power of 10, for example,
-but other operations are not likely to be what you intend.  For example:
-
-  $VERSION = version->new((qw$Revision: 1.4)[1]/10);
-  print $VERSION;          # yields 0.14
-  $V2 = version->new(100/9); # Integer overflow in decimal number
-  print $V2;               # yields something like 11.111.111.100
-
-Perl 5.8.1 and beyond will be able to automatically quote v-strings but
-that is not possible in earlier versions of Perl.  In other words:
-
-  $version = version->new("v2.5.4");  # legal in all versions of Perl
-  $newvers = version->new(v2.5.4);    # legal only in Perl >= 5.8.1
-
-=head1 SUBCLASSING
-
-This module is specifically designed and tested to be easily subclassed.
-In practice, you only need to override the methods you want to change, but
-you have to take some care when overriding new() (since that is where all
-of the parsing takes place).  For example, this is a perfect acceptable
-derived class:
-
-  package myversion;
-  use base version;
-  sub new { 
-      my($self,$n)=@_;
-      my $obj;
-      # perform any special input handling here
-      $obj = $self->SUPER::new($n);
-      # and/or add additional hash elements here
-      return $obj;
-  }
-
-See also L<version::AlphaBeta> on CPAN for an alternate representation of
-version strings.
-
-B<NOTE:> Although the L<qv> operator is not a true class method, but rather a
-function exported into the caller's namespace, a subclass of version will 
-inherit an import() function which will perform the correct magic on behalf
-of the subclass.
-
-=head1 EXPORT
-
-qv - Dotted-Decimal Version initialization operator
-
 =head1 AUTHOR
 
 John Peacock E<lt>jpeacock@cpan.orgE<gt>
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index f80bdcd6dc..543604282e 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -1851,9 +1851,17 @@ earlier in the line, and you really meant a "less than".
 
 =item gmtime(%.0f) too large
 
-(W overflow) You called C<gmtime> with an number that was beyond the 64-bit
-range that it accepts, and some rounding resulted. This warning is also
-triggered with nan (the special not-a-number value).
+(W overflow) You called C<gmtime> with an number that was larger than
+it can reliably handle and C<gmtime> probably returned the wrong
+date. This warning is also triggered with nan (the special
+not-a-number value).
+
+=item gmtime(%.0f) too small
+
+(W overflow) You called C<gmtime> with an number that was smaller than
+it can reliably handle and C<gmtime> probably returned the wrong
+date. This warning is also triggered with nan (the special
+not-a-number value).
 
 =item Got an error from DosAllocMem
 
@@ -2289,8 +2297,17 @@ L<perlfunc/listen>.
 
 =item localtime(%.0f) too large
 
-(W overflow) You called C<localtime> with an number that was beyond the
-64-bit range that it accepts, and some rounding resulted. This warning is also triggered with nan (the special not-a-number value).
+(W overflow) You called C<localtime> with an number that was larger
+than it can reliably handle and C<localtime> probably returned the
+wrong date. This warning is also triggered with nan (the special
+not-a-number value).
+
+=item localtime(%.0f) too small
+
+(W overflow) You called C<localtime> with an number that was smaller
+than it can reliably handle and C<localtime> probably returned the
+wrong date. This warning is also triggered with nan (the special
+not-a-number value).
 
 =item Lookbehind longer than %d not implemented in regex m/%s/
 
diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 14582f5a9c..18787fe0fd 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -1176,21 +1176,25 @@ See also L</undef>, L</exists>, L</ref>.
 =item delete EXPR
 X<delete>
 
-Given an expression that specifies an element or slice of an aggregate (a
-hash or an array), deletes the specified elements from that aggregate so
-that exists() on that element no longer returns true.  Setting an aggregate
-element to the undefined value does not remove its key, but deleting it
-does; see L</exists>.
+Given an expression that specifies an element or slice of a hash, C<delete>
+deletes the specified elements from that hash so that exists() on that element
+no longer returns true.  Setting a hash element to the undefined value does
+not remove its key, but deleting it does; see L</exists>.
 
-Returns the value or values deleted in list context, or the last such
+It returns the value or values deleted in list context, or the last such
 element in scalar context.  The return list's length always matches that of
-the argument list: deleting non-existent elements returns the undefined
-value in their corresponding positions.
+the argument list: deleting non-existent elements returns the undefined value
+in their corresponding positions.
 
-Deleting array elements never changes indices of existing values; use
-shift() or splice() for that.  However, if all deleted elements fall at
-the end of an array, the array's size shrinks to the position of the
-highest element that still tests true for exists(), or to 0 if none do.
+delete() may also be used on arrays and array slices, but its behavior is less
+straightforward.  Although exists() will return false for deleted entries,
+deleting array elements never changes indices of existing values; use shift()
+or splice() for that.  However, if all deleted elements fall at the end of an
+array, the array's size shrinks to the position of the highest element that
+still tests true for exists(), or to 0 if none do.
+
+B<Be aware> that calling delete on array values is deprecated and likely to
+be removed in a future version of Perl.
 
 Deleting from C<%ENV> modifies the environment.  Deleting from a hash tied to
 a DBM file deletes the entry from the DBM file.  Deleting from a C<tied> hash
@@ -1740,14 +1744,19 @@ C<DESTROY> methods on your objects.
 =item exists EXPR
 X<exists> X<autovivification>
 
-Given an expression that specifies an element of a hash or array,
-returns true if the specified element in that aggregate has ever
-been initialized, even if the corresponding value is undefined.
+Given an expression that specifies an element of a hash, returns true if the
+specified element in the hash has ever been initialized, even if the
+corresponding value is undefined.
 
     print "Exists\n"    if exists $hash{$key};
     print "Defined\n"   if defined $hash{$key};
     print "True\n"      if $hash{$key};
 
+exists may also be called on array elements, but its behavior is much less
+obvious, and is strongly tied to the use of L</delete> on arrays.  B<Be aware>
+that calling exists on array values is deprecated and likely to be removed in
+a future version of Perl.
+
     print "Exists\n"    if exists $array[$index];
     print "Defined\n"   if defined $array[$index];
     print "True\n"      if $array[$index];
diff --git a/pp_sys.c b/pp_sys.c
index 8b5fccbd97..e7cdb594b8 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -4485,6 +4485,15 @@ PP(pp_tms)
 #endif /* HAS_TIMES */
 }
 
+/* The 32 bit int year limits the times we can represent to these
+   boundaries with a few days wiggle room to account for time zone
+   offsets
+*/
+/* Sat Jan  3 00:00:00 -2147481748 */
+#define TIME_LOWER_BOUND -67768100567755200.0
+/* Sun Dec 29 12:00:00  2147483647 */
+#define TIME_UPPER_BOUND  67767976233316800.0
+
 PP(pp_gmtime)
 {
     dVAR;
@@ -4513,10 +4522,22 @@ PP(pp_gmtime)
 	}
     }
 
-    if (PL_op->op_type == OP_LOCALTIME)
-        err = S_localtime64_r(&when, &tmbuf);
-    else
-	err = S_gmtime64_r(&when, &tmbuf);
+    if ( TIME_LOWER_BOUND > when ) {
+	Perl_ck_warner(aTHX_ packWARN(WARN_OVERFLOW),
+		       "%s(%.0f) too small", opname, when);
+	err = NULL;
+    }
+    else if( when > TIME_UPPER_BOUND ) {
+	Perl_ck_warner(aTHX_ packWARN(WARN_OVERFLOW),
+		       "%s(%.0f) too large", opname, when);
+	err = NULL;
+    }
+    else {
+	if (PL_op->op_type == OP_LOCALTIME)
+	    err = S_localtime64_r(&when, &tmbuf);
+	else
+	    err = S_gmtime64_r(&when, &tmbuf);
+    }
 
     if (err == NULL) {
 	/* XXX %lld broken for quads */
diff --git a/t/op/time.t b/t/op/time.t
index 5515634343..84eaf752f3 100644
--- a/t/op/time.t
+++ b/t/op/time.t
@@ -1,4 +1,4 @@
-#!./perl
+#!./perl -w
 
 BEGIN {
     chdir 't' if -d 't';
@@ -6,7 +6,7 @@ BEGIN {
     require './test.pl';
 }
 
-plan tests => 56;
+plan tests => 62;
 
 # These tests make sure, among other things, that we don't end up
 # burning tons of CPU for dates far in the future.
@@ -36,9 +36,9 @@ ok($i >= 2_000_000, 'very basic times test');
 ($xsec,$foo) = localtime($now);
 $localyday = $yday;
 
-isnt($sec, $xsec),      'localtime() list context';
-ok $mday,               '  month day';
-ok $year,               '  year';
+isnt($sec, $xsec,      'localtime() list context');
+ok $mday,              '  month day';
+ok $year,              '  year';
 
 ok(localtime() =~ /^(Sun|Mon|Tue|Wed|Thu|Fri|Sat)[ ]
                     (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[ ]
@@ -66,9 +66,9 @@ ok($hour != $hour2,                             'changes to $ENV{TZ} respected')
 ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = gmtime($beg);
 ($xsec,$foo) = localtime($now);
 
-isnt($sec, $xsec),      'gmtime() list conext';
-ok $mday,               '  month day';
-ok $year,               '  year';
+isnt($sec, $xsec,      'gmtime() list conext');
+ok $mday,              '  month day';
+ok $year,              '  year';
 
 my $day_diff = $localyday - $yday;
 ok( grep({ $day_diff == $_ } (0, 1, -1, 364, 365, -364, -365)),
@@ -142,12 +142,12 @@ ok(gmtime() =~ /^(Sun|Mon|Tue|Wed|Thu|Fri|Sat)[ ]
 {
     eval {
         $SIG{__WARN__} = sub { die @_; };
-        localtime(1.23);
+        is( (localtime(1296000.23))[5] + 1900, 1970 );
     };
     is($@, '', 'Ignore fractional time');
     eval {
         $SIG{__WARN__} = sub { die @_; };
-        gmtime(1.23);
+        is( (gmtime(1.23))[5] + 1900, 1970 );
     };
     is($@, '', 'Ignore fractional time');
 }
@@ -174,3 +174,29 @@ ok(gmtime() =~ /^(Sun|Mon|Tue|Wed|Thu|Fri|Sat)[ ]
         is $have, $want, "year check, localtime($time)";
     }
 }
+
+
+# Test that Perl warns properly when it can't handle a time.
+{
+    my $warning;
+    local $SIG{__WARN__} = sub { $warning .= join "\n", @_; };
+
+    my $big_time   = 2**60;
+    my $small_time = -2**60;
+
+    $warning = '';
+    my $date = gmtime($big_time);
+    like $warning, qr/^gmtime(.*) too large/;
+
+    $warning = '';
+    $date = localtime($big_time);
+    like $warning, qr/^localtime(.*) too large/;
+
+    $warning = '';
+    $date = gmtime($small_time);
+    like $warning, qr/^gmtime(.*) too small/;
+
+    $warning = '';
+    $date = localtime($small_time);
+    like $warning, qr/^localtime(.*) too small/;
+}
diff --git a/t/op/time_loop.t b/t/op/time_loop.t
new file mode 100644
index 0000000000..6f4acdc1f9
--- /dev/null
+++ b/t/op/time_loop.t
@@ -0,0 +1,16 @@
+#!perl -w
+
+# d95a2ea538e6c332f36c34ca45b78d6ad93c3a1f allowed times greater than
+# 2**63 to be handed to gm/localtime() which caused an internal overflow
+# and an excessively long loop.  Test this does not happen.
+
+use strict;
+
+BEGIN { require './test.pl'; }
+
+plan tests => 2;
+watchdog(2);
+
+local $SIG{__WARN__} = sub {};
+is gmtime(2**69),    undef;
+is localtime(2**69), undef;