text: (This article was first published on Revolutions, and kindly contributed to R-bloggers)
  The next release of R is scheduled for release February 25, and R 2.12.2 will likely be the final bug-fix release of the 2.12 series before R 2.13 is released in April. According to the NEWS file in the latest daily build, 2.12.2 will improve complex-arithmetic support on some rare platforms that don't support complex types in C99, and upgrades the PCRE library begind regular-expression functions like regex. There will also a number of minor big-fixes, mainly addressing rare edge-cases. The corresponding section of the current NEWS file is included after the jump, but of course there may be additional changes or fixes documented before the February 25 release.
  r-announce mailing list: R 2.12.2 scheduled for February 25
  CHANGES IN R VERSION 2.12.1 patched: SIGNIFICANT USER-VISIBLE CHANGES: o Complex arithmetic (notably z^n for complex z and integer n) gave incorrect results since R 2.10.0 on platforms without complex). o There is a workaround for crashes seen with several packages on systems using zlib 1.2.5: see the INSTALLATION section. NEW FEATURES: o PCRE has been updated to 8.12 (two bug-fix releases since 8.10). o rep(), seq(), seq.int() and seq_len() report more often when the first element is taken of an argument of incorrect length. o The Cocoa back-end for the quartz() graphics device on Mac OS X provides a way to disable event loop processing temporarily (useful, e.g., for forked instances of R). o kernel()'s default for m was not appropriate if coef was a set of coefficients. (Reported by Pierre Chausse.) INSTALLATION: o The zlib sources in the distribution are now built with all symbols remapped: this is intended to avoid problems seen with packages such as XML and rggobi which link to zlib.so.1 on systems using zlib 1.2.5. o The default for FFLAGS and FCFLAGS with gfortran on x86_64 Linux has been changed back to -g -O2: however, setting -g -O may still be needed for gfortran 4.3.x. PACKAGE INSTALLATION: o A LazyDataCompression field in the DESCRIPTION file will be used to set the value for the --data-compress option of R CMD INSTALL. o Files R/sysdata.rda of more than 1Mb are now stored in the lazyload daabase using xz compression: this for example halves the installed size of package Imap. o R CMD INSTALL now ensures that directories installed from inst have search permission for everyone. DEPRECATED & DEFUNCT: o The 'experimental' alternative specification of a name space via .Export() etc is now deprecated. o zip.file.extract() is now deprecated. o Zip-ing data sets in packages (and hence R CMD INSTALL --use-zip-data and the ZipData: yes field in a DESCRIPTION file) is deprecated: using efficiently compressed .rda images and lazy-loading of data has superseded it. BUG FIXES: o identical could in rare cases generate a warning about non-pairlist attributes on CHARSXPs. As these are used for internal purposes, the attribute check should be skipped. (Reported by Niels Richard Hansen). o If the filename extension (usually .Rnw) was not included in a call to Sweave(), source references would not work properly, and the keep.source option failed. (PR#14459) o format.data.frame() now keeps zero character column names. o pretty(x) no longer raises an error when x contains solely non-finite values. (PR#14468) o The plot.TukeyHSD() function now uses a line width of 0.5 for its reference lines rather than lwd = 0 (which caused problems for some PDF and PostScript viewers). o The big.mark argument to prettyNum(), format(), etc. was inserted reversed if it was more than one character long. o R CMD check failed to check the filenames under man for Windows' reserved names. o The "Date" and "POSIXt" methods for seq() could overshoot when to was supplied and by was specified in months or years. o The internal method of untar() now restores hard links as file copies rather than symbolic links (which did not work for cross-directory links). o.) o combn(n, m) now behaves more regularly for the border case m = 0. (PR#14473) o The rendering of numbers in plotmath expressions (e.g. expression(10^2)) used the current settings for conversion to strings rather than setting the defaults, and so could be affected by what has been done before. (PR#14477) o The methods of napredict() and naresid() for na.action = na.exclude fits did not work correctly in the very rare event that every case had been omitted in the fit. (Reported by Simon Wood.) o weighted.residuals(drop0=TRUE) returned a vector when the residuals were a matrix (e.g. those of class "mlm"). (Reported by Bill Dunlap.) o Package HTML index files /html/00Index.html were generated with a stylesheet reference that was not correct for static browsing in libraries. o ccf(na.action = na.pass) was not implemented. o The parser accepted some incorrect numeric constants, e.g. 20x2. (Reported by Olaf Mersmann.) o format(*, zero.print) did not always replace the full zero parts. o Fixes for subsetting or subassignment of "raster" objects when not both i and j are specified. o. o source(file, echo=TRUE) could fail if the file contained #line directives. It now recovers more gracefully, but may still display the wrong line if the directive gives incorrect information. o atan(1i) returned NaN+Infi (rather than 0+Infi) on platforms without C99 complex support. o library() failed to cache S4 metadata (unlike loadNamespace()) causing failures in S4-using packages without a namespace (e.g. those using reference classes). o The logit() function qlogis(lp, log.p=TRUE) no longer prematurely overflows to Inf when p := exp(lp) is close to 1. o Updating S4 methods for a group generic function requires resetting the methods tables for the members of the group (patch contributed by Martin Morgan). o In some circumstances (including for package XML), R CMD INSTALL installed version-control directories from source packages. o Added PROTECT calls to some constructed expressions used in C level eval calls....