Documentation / RelNotes / 2.2.0.txton commit Merge branch 'nd/switch-and-restore' (3ff6af7)
   1Git v2.2 Release Notes
   2======================
   3
   4Updates since v2.1
   5------------------
   6
   7Ports
   8
   9 * Building on older MacOS X systems automatically sets
  10   the necessary NO_APPLE_COMMON_CRYPTO build-time option.
  11
  12 * Building with NO_PTHREADS has been resurrected.
  13
  14 * Compilation options have been updated a bit to better support the
  15   z/OS port.
  16
  17
  18UI, Workflows & Features
  19
  20 * "git archive" learned to filter what gets archived with a pathspec.
  21
  22 * "git config --edit --global" starts from a skeletal per-user
  23   configuration file contents, instead of a total blank, when the
  24   user does not already have any global config.  This immediately
  25   reduces the need to later ask "Have you forgotten to set
  26   core.user?", and we can add more to the template as we gain
  27   more experience.
  28
  29 * "git stash list -p" used to be almost always a no-op because each
  30   stash entry is represented as a merge commit.  It learned to show
  31   the difference between the base commit version and the working tree
  32   version, which is in line with what "git stash show" gives.
  33
  34 * Sometimes users want to report a bug they experience on their
  35   repository, but they are not at liberty to share the contents of
  36   the repository.  "fast-export" was taught an "--anonymize" option
  37   to replace blob contents, names of people, paths and log
  38   messages with bland and simple strings to help them.
  39
  40 * "git difftool" learned an option to stop feeding paths to the
  41   diff backend when it exits with a non-zero status.
  42
  43 * "git grep" learned to paint (or not paint) partial matches on
  44   context lines when showing "grep -C<num>" output in color.
  45
  46 * "log --date=iso" uses a slight variant of the ISO 8601 format that is
  47   more human readable.  A new "--date=iso-strict" option gives
  48   datetime output that conforms more strictly.
  49
  50 * The logic "git prune" uses is more resilient against various corner
  51   cases.
  52
  53 * A broken reimplementation of Git could write an invalid index that
  54   records both stage #0 and higher-stage entries for the same path.
  55   We now notice and reject such an index, as there is no sensible
  56   fallback (we do not know if the broken tool wanted to resolve and
  57   forgot to remove the higher-stage entries, or if it wanted to unresolve
  58   and forgot to remove the stage #0 entry).
  59
  60 * The temporary files "git mergetool" uses are renamed to avoid too
  61   many dots in them (e.g. a temporary file for "hello.c" used to be
  62   named e.g. "hello.BASE.4321.c" but now uses underscore instead,
  63   e.g. "hello_BASE_4321.c", to allow us to have multiple variants).
  64
  65 * The temporary files "git mergetool" uses can be placed in a newly
  66   created temporary directory, instead of the current directory, by
  67   setting the mergetool.writeToTemp configuration variable.
  68
  69 * "git mergetool" understands "--tool bc" now, as version 4 of
  70   BeyondCompare can be driven the same way as its version 3 and it
  71   feels awkward to say "--tool bc3" to run version 4.
  72
  73 * The "pre-receive" and "post-receive" hooks are no longer required
  74   to consume their input fully (not following this requirement used
  75   to result in intermittent errors in "git push").
  76
  77 * The pretty-format specifier "%d", which expands to " (tagname)"
  78   for a tagged commit, gained a cousin "%D" that just gives the
  79   "tagname" without frills.
  80
  81 * "git push" learned "--signed" push, that allows a push (i.e.
  82   request to update the refs on the other side to point at a new
  83   history, together with the transmission of necessary objects) to be
  84   signed, so that it can be verified and audited, using the GPG
  85   signature of the person who pushed, that the tips of branches at a
  86   public repository really point the commits the pusher wanted to,
  87   without having to "trust" the server.
  88
  89 * "git interpret-trailers" is a new filter to programmatically edit
  90   the tail end of the commit log messages, e.g. "Signed-off-by:".
  91
  92 * "git help everyday" shows the "Everyday Git in 20 commands or so"
  93   document, whose contents have been updated to match more modern
  94   Git practice.
  95
  96 * On the "git svn" front, work progresses to reduce memory consumption and
  97   to improve handling of mergeinfo.
  98
  99
 100Performance, Internal Implementation, Development Support etc.
 101
 102 * The API to manipulate the "refs" has been restructured to make it
 103   more transactional, with the eventual goal to allow all-or-none
 104   atomic updates and migrating the storage to something other than
 105   the traditional filesystem based one (e.g. databases).
 106
 107 * The lockfile API and its users have been cleaned up.
 108
 109 * We no longer attempt to keep track of individual dependencies to
 110   the header files in the build procedure, relying instead on automated
 111   dependency generation support from modern compilers.
 112
 113 * In tests, we have been using NOT_{MINGW,CYGWIN} test prerequisites
 114   long before negated prerequisites e.g. !MINGW were invented.
 115   The former has been converted to the latter to avoid confusion.
 116
 117 * Optimized looking up a remote's configuration in a repository with very many
 118   remotes defined.
 119
 120 * There are cases where you lock and open to write a file, close it
 121   to show the updated contents to an external processes, and then have
 122   to update the file again while still holding the lock; now the
 123   lockfile API has support for such an access pattern.
 124
 125 * The API to allocate the structure to keep track of commit
 126   decoration has been updated to make it less cumbersome to use.
 127
 128 * An in-core caching layer to let us avoid reading the same
 129   configuration files several times has been added.  A few commands
 130   have been converted to use this subsystem.
 131
 132 * Various code paths have been cleaned up and simplified by using
 133   the "strbuf", "starts_with()", and "skip_prefix()" APIs more.
 134
 135 * A few codepaths that died when large blobs that would not fit in
 136   core are involved in their operation have been taught to punt
 137   instead, by e.g. marking a too-large blob as not to be diffed.
 138
 139 * A few more code paths in "commit" and "checkout" have been taught
 140   to repopulate the cache-tree in the index, to help speed up later
 141   "write-tree" (used in "commit") and "diff-index --cached" (used in
 142   "status").
 143
 144 * A common programming mistake to assign the same short option name
 145   to two separate options is detected by the parse_options() API to help
 146   developers.
 147
 148 * The code path to write out the packed-refs file has been optimized,
 149   which especially matters in a repository with a large number of
 150   refs.
 151
 152 * The check to see if a ref $F can be created by making sure no
 153   existing ref has $F/ as its prefix has been optimized, which
 154   especially matters in a repository with a large number of existing
 155   refs.
 156
 157 * "git fsck" was taught to check the contents of tag objects a bit more.
 158
 159 * "git hash-object" was taught a "--literally" option to help
 160   debugging.
 161
 162 * When running a required clean filter, we do not have to mmap the
 163   original before feeding the filter.  Instead, stream the file
 164   contents directly to the filter and process its output.
 165
 166 * The scripts in the test suite can be run with the "-x" option to show
 167   a shell-trace of each command they run.
 168
 169 * The "run-command" API learned to manage the argv and environment
 170   arrays for child process, alleviating the need for the callers to
 171   allocate and deallocate them.
 172
 173 * Some people use AsciiDoctor, instead of AsciiDoc, to format our
 174   documentation set; the documentation has been adjusted to be usable
 175   by both, as AsciiDoctor is pickier than AsciiDoc about its input
 176   mark-up.
 177
 178
 179Also contains various documentation updates and code clean-ups.
 180
 181
 182Fixes since v2.1
 183----------------
 184
 185Unless otherwise noted, all the fixes since v2.1 in the maintenance
 186track are contained in this release (see the maintenance releases'
 187notes for details).
 188
 189 * "git log --pretty/format=" with an empty format string did not
 190   mean the more obvious "No output whatsoever" but "Use default
 191   format", which was counterintuitive.
 192
 193 * "git -c section.var command" and "git -c section.var= command"
 194   should pass the configuration value differently (the former should be a
 195   boolean true, the latter should be an empty string).
 196
 197 * Applying a patch not generated by Git in a subdirectory used to
 198   check for whitespace breakage using the attributes of incorrect
 199   paths. Also whitespace checks were performed even for paths
 200   excluded via the "git apply --exclude=<path>" mechanism.
 201
 202 * "git bundle create" with a date-range specification was meant to
 203   exclude tags outside the range, but it didn't.
 204
 205 * "git add x" where x used to be a directory and is now a
 206   symbolic link to a directory misbehaved.
 207
 208 * The prompt script checked the $GIT_DIR/ref/stash file to see if there
 209   is a stash, which was a no-no.
 210
 211 * Pack-protocol documentation had a minor typo.
 212
 213 * "git checkout -m" did not switch to another branch while carrying
 214   the local changes forward when a path was deleted from the index.
 215
 216 * "git daemon" (with NO_IPV6 build configuration) used to incorrectly
 217   use the hostname even when gethostbyname() reported that the given
 218   hostname is not found.
 219   (merge 107efbe rs/daemon-fixes later to maint).
 220
 221 * With sufficiently long refnames, "git fast-import" could have
 222   overflowed an on-stack buffer.
 223
 224 * After "pack-refs --prune" packed refs at the top-level, it failed
 225   to prune them.
 226
 227 * Progress output from "git gc --auto" was visible in "git fetch -q".
 228
 229 * We used to pass -1000 to poll(2), expecting it to also mean "no
 230   timeout", which should be spelled as -1.
 231
 232 * "git rebase" documentation was unclear that it is required to
 233   specify on what <upstream> the rebase is to be done when telling it
 234   to first check out <branch>.
 235   (merge 95c6826 so/rebase-doc later to maint).
 236
 237 * "git push" over HTTP transport had an artificial limit on the number of
 238   refs that can be pushed, imposed by the command line length.
 239   (merge 26be19b jk/send-pack-many-refspecs later to maint).
 240
 241 * When receiving an invalid pack stream that records the same object
 242   twice, multiple threads got confused due to a race.
 243   (merge ab791dd jk/index-pack-threading-races later to maint).
 244
 245 * An attempt to remove the entire tree in the "git fast-import" input
 246   stream caused it to misbehave.
 247   (merge 2668d69 mb/fast-import-delete-root later to maint).
 248
 249 * Reachability check (used in "git prune" and friends) did not add a
 250   detached HEAD as a starting point to traverse objects still in use.
 251   (merge c40fdd0 mk/reachable-protect-detached-head later to maint).
 252
 253 * "git config --add section.var val" when section.var already has an
 254   empty-string value used to lose the empty-string value.
 255   (merge c1063be ta/config-add-to-empty-or-true-fix later to maint).
 256
 257 * "git fsck" failed to report that it found corrupt objects via its
 258   exit status in some cases.
 259   (merge 30d1038 jk/fsck-exit-code-fix later to maint).
 260
 261 * Use of the "--verbose" option used to break "git branch --merged".
 262   (merge 12994dd jk/maint-branch-verbose-merged later to maint).
 263
 264 * Some MUAs mangle a line in a message that begins with "From " to
 265   ">From " when writing to a mailbox file, and feeding such an input
 266   to "git am" used to lose such a line.
 267   (merge 85de86a jk/mbox-from-line later to maint).
 268
 269 * "rev-parse --verify --quiet $name" is meant to quietly exit with a
 270   non-zero status when $name is not a valid object name, but still
 271   gave error messages in some cases.
 272
 273 * A handful of C source files have been updated to include
 274   "git-compat-util.h" as the first thing, to conform better to our
 275   coding guidelines.
 276   (merge 1c4b660 da/include-compat-util-first-in-c later to maint).
 277
 278 * The t7004 test, which tried to run Git with small stack space, has been
 279   updated to use a bit larger stack to avoid false breakage on some
 280   platforms.
 281   (merge b9a1907 sk/tag-contains-wo-recursion later to maint).
 282
 283 * A few documentation pages had example sections marked up not quite
 284   correctly, which passed AsciiDoc but failed with AsciiDoctor.
 285   (merge c30c43c bc/asciidoc-pretty-formats-fix later to maint).
 286   (merge f8a48af bc/asciidoc later to maint).
 287
 288 * "gitweb" used deprecated CGI::startfrom, which was removed from
 289   CGI.pm as of 4.04; use CGI::start_from instead.
 290   (merge 4750f4b rm/gitweb-start-form later to maint).
 291
 292 * Newer versions of 'meld' break the auto-detection we use to see if
 293   they are new enough to support the `--output` option.
 294   (merge b12d045 da/mergetool-meld later to maint).
 295
 296 * "git pack-objects" forgot to disable the codepath to generate the
 297   object reachability bitmap when it needs to split the resulting
 298   pack.
 299   (merge 2113471 jk/pack-objects-no-bitmap-when-splitting later to maint).
 300
 301 * The code to use cache-tree trusted the on-disk data too much and
 302   fell into an infinite loop upon seeing an incorrectly recorded
 303   index file.
 304   (merge 729dbbd jk/cache-tree-protect-from-broken-libgit2 later to maint).
 305
 306 * "git fetch" into a repository where branch B was deleted earlier,
 307   back when it had reflog enabled, and then branch B/C is fetched
 308   into it without reflog enabled, which is arguably an unlikely
 309   corner case, unnecessarily failed.
 310   (merge aae828b jk/fetch-reflog-df-conflict later to maint).
 311
 312 * "git log --first-parent -L..." used to crash.
 313   (merge a8787c5 tm/line-log-first-parent later to maint).