Documentation / RelNotes / 2.9.0.txton commit Merge branch 'jk/diff-compact-heuristic' (0018da1)
   1Git 2.9 Release Notes
   2=====================
   3
   4Backward compatibility note
   5---------------------------
   6
   7The end-user facing Porcelain level commands in the "git diff" and
   8"git log" by default enables the rename detection; you can still use
   9"diff.renames" configuration variable to disable this.
  10
  11Merging two branches that have no common ancestor with "git merge" is
  12by default forbidden now to prevent creating such an unusual merge by
  13mistake.
  14
  15The output formats of "git log" that indents the commit log message by
  164 spaces now expands HT in the log message by default.  You can use
  17the "--no-expand-tabs" option to disable this.
  18
  19
  20Updates since v2.8
  21------------------
  22
  23UI, Workflows & Features
  24
  25 * The end-user facing Porcelain level commands like "diff" and "log"
  26   now enables the rename detection by default.
  27
  28 * The credential.helper configuration variable is cumulative and
  29   there is no good way to override it from the command line.  As
  30   a special case, giving an empty string as its value now serves
  31   as the signal to clear the values specified in various files.
  32
  33 * A new "interactive.diffFilter" configuration can be used to
  34   customize the diff shown in "git add -i" session.
  35
  36 * "git p4" now allows P4 author names to be mapped to Git author
  37   names.
  38
  39 * "git rebase -x" can be used without passing "-i" option.
  40
  41 * "git -c credential.<var>=<value> submodule" can now be used to
  42   propagate configuration variables related to credential helper
  43   down to the submodules.
  44
  45 * "git tag" can create an annotated tag without explicitly given an
  46   "-a" (or "-s") option (i.e. when a tag message is given).  A new
  47   configuration variable, tag.forceSignAnnotated, can be used to tell
  48   the command to create signed tag in such a situation.
  49
  50 * "git merge" used to allow merging two branches that have no common
  51   base by default, which led to a brand new history of an existing
  52   project created and then get pulled by an unsuspecting maintainer,
  53   which allowed an unnecessary parallel history merged into the
  54   existing project.  The command has been taught not to allow this by
  55   default, with an escape hatch "--allow-unrelated-histories" option
  56   to be used in a rare event that merges histories of two projects
  57   that started their lives independently.
  58
  59 * "git pull" has been taught to pass --allow-unrelated-histories
  60   option to underlying "git merge".
  61
  62 * "git apply -v" learned to report paths in the patch that were
  63   skipped via --include/--exclude mechanism or being outside the
  64   current working directory.
  65
  66 * Shell completion (in contrib/) updates.
  67
  68 * The commit object name reported when "rebase -i" stops has been
  69   shortened.
  70
  71 * "git worktree add" can be given "--no-checkout" option to only
  72   create an empty worktree without checking out the files.
  73
  74 * "git mergetools" learned to drive ExamDiff.
  75
  76 * "git pull --rebase" learned "--[no-]autostash" option, so that
  77   the rebase.autostash configuration variable set to true can be
  78   overridden from the command line.
  79
  80 * When "git log" shows the log message indented by 4-spaces, the
  81   remainder of a line after a HT does not align in the way the author
  82   originally intended.  The command now expands tabs by default in
  83   such a case, and allows the users to override it with a new option,
  84   "--no-expand-tabs".
  85
  86 * "git send-email" now uses a more readable timestamps when
  87   formulating a message ID.
  88
  89 * "git rerere" can encounter two or more files with the same conflict
  90   signature that have to be resolved in different ways, but there was
  91   no way to record these separate resolutions.
  92   (merge 890fca8 jc/rerere-multi later to maint).
  93
  94 * "git p4" learned to record P4 jobs in Git commit that imports from
  95   the history in Perforce.
  96
  97 * "git describe --contains" often made a hard-to-justify choice of
  98   tag to give name to a given commit, because it tried to come up
  99   with a name with smallest number of hops from a tag, causing an old
 100   commit whose close descendant that is recently tagged were not
 101   described with respect to an old tag but with a newer tag.  It did
 102   not help that its computation of "hop" count was further tweaked to
 103   penalize being on a side branch of a merge.  The logic has been
 104   updated to favor using the tag with the oldest tagger date, which
 105   is a lot easier to explain to the end users: "We describe a commit
 106   in terms of the (chronologically) oldest tag that contains the
 107   commit."
 108   (merge 7550424 js/name-rev-use-oldest-ref later to maint).
 109
 110
 111Performance, Internal Implementation, Development Support etc.
 112
 113 * The embedded args argv-array in the child process is used to build
 114   the command line to run pack-objects instead of using a separate
 115   array of strings.
 116
 117 * A test for tags has been restructured so that more parts of it can
 118   easily be run on a platform without a working GnuPG.
 119
 120 * The startup_info data, which records if we are working inside a
 121   repository (among other things), are now uniformly available to Git
 122   subcommand implementations, and Git avoids attempting to touch
 123   references when we are not in a repository.
 124
 125 * The command line argument parser for "receive-pack" has been
 126   rewritten to use parse-options.
 127
 128 * A major part of "git submodule update" has been ported to C to take
 129   advantage of the recently added framework to run download tasks in
 130   parallel.
 131
 132 * Rename bunch of tests on "git clone" for better organization.
 133
 134 * The tests that involve running httpd leaked the system-wide
 135   configuration in /etc/gitconfig to the tested environment.
 136
 137 * Build updates for MSVC.
 138
 139 * The repository set-up sequence has been streamlined (the biggest
 140   change is that there is no longer git_config_early()), so that we
 141   do not attempt to look into refs/* when we know we do not have a
 142   Git repository.
 143
 144 * Code restructuring around the "refs" area to prepare for pluggable
 145   refs backends.
 146
 147 * Sources to many test helper binaries (and the generated helpers)
 148   have been moved to t/helper/ subdirectory to reduce clutter at the
 149   top level of the tree.
 150
 151   Note that this can break your tests if you check out revisions
 152   across the merge boundary of this topic, e0b58519 (Merge branch
 153   'nd/test-helpers', 2016-04-29), as bin-wrappers/test-* are not
 154   rebuilt to point the underlying executables.  For now, "make
 155   distclean" is your friend.
 156
 157 * Unify internal logic between "git tag -v" and "git verify-tag"
 158   commands by making one directly call into the other.
 159   (merge bef234b st/verify-tag later to maint).
 160
 161 * "merge-recursive" strategy incorrectly checked if a path that is
 162   involved in its internal merge exists in the working tree.
 163
 164
 165Also contains various documentation updates and code clean-ups.
 166
 167
 168Fixes since v2.8
 169----------------
 170
 171Unless otherwise noted, all the fixes since v2.8 in the maintenance
 172track are contained in this release (see the maintenance releases'
 173notes for details).
 174
 175 * "git config --get-urlmatch", unlike other variants of the "git
 176   config --get" family, did not signal error with its exit status
 177   when there was no matching configuration.
 178
 179 * The "--local-env-vars" and "--resolve-git-dir" options of "git
 180   rev-parse" failed to work outside a repository when the command's
 181   option parsing was rewritten in 1.8.5 era.
 182
 183 * "git index-pack --keep[=<msg>] pack-$name.pack" simply did not work.
 184
 185 * Fetching of history by naming a commit object name directly didn't
 186   work across remote-curl transport.
 187
 188 * A small memory leak in an error codepath has been plugged in xdiff
 189   code.
 190
 191 * strbuf_getwholeline() did not NUL-terminate the buffer on certain
 192   corner cases in its error codepath.
 193
 194 * "git mergetool" did not work well with conflicts that both sides
 195   deleted.
 196
 197 * "git send-email" had trouble parsing alias file in mailrc format
 198   when lines in it had trailing whitespaces on them.
 199
 200 * When "git merge --squash" stopped due to conflict, the concluding
 201   "git commit" failed to read in the SQUASH_MSG that shows the log
 202   messages from all the squashed commits.
 203
 204 * "git merge FETCH_HEAD" dereferenced NULL pointer when merging
 205   nothing into an unborn history (which is arguably unusual usage,
 206   which perhaps was the reason why nobody noticed it).
 207
 208 * When "git worktree" feature is in use, "git branch -d" allowed
 209   deletion of a branch that is checked out in another worktree,
 210   which was wrong.
 211
 212 * When "git worktree" feature is in use, "git branch -m" renamed a
 213   branch that is checked out in another worktree without adjusting
 214   the HEAD symbolic ref for the worktree.
 215
 216 * "git diff -M" used to work better when two originally identical
 217   files A and B got renamed to X/A and X/B by pairing A to X/A and B
 218   to X/B, but this was broken in the 2.0 timeframe.
 219
 220 * "git send-pack --all <there>" was broken when its command line
 221   option parsing was written in the 2.6 timeframe.
 222
 223 * "git format-patch --help" showed `-s` and `--no-patch` as if these
 224   are valid options to the command.  We already hide `--patch` option
 225   from the documentation, because format-patch is about showing the
 226   diff, and the documentation now hides these options as well.
 227
 228 * When running "git blame $path" with unnormalized data in the index
 229   for the path, the data in the working tree was blamed, even though
 230   "git add" would not have changed what is already in the index, due
 231   to "safe crlf" that disables the line-end conversion.  It has been
 232   corrected.
 233
 234 * A change back in version 2.7 to "git branch" broke display of a
 235   symbolic ref in a non-standard place in the refs/ hierarchy (we
 236   expect symbolic refs to appear in refs/remotes/*/HEAD to point at
 237   the primary branch the remote has, and as .git/HEAD to point at the
 238   branch we locally checked out).
 239
 240 * A partial rewrite of "git submodule" in the 2.7 timeframe changed
 241   the way the gitdir: pointer in the submodules point at the real
 242   repository location to use absolute paths by accident.  This has
 243   been corrected.
 244
 245 * "git commit" misbehaved in a few minor ways when an empty message
 246   is given via -m '', all of which has been corrected.
 247
 248 * Support for CRAM-MD5 authentication method in "git imap-send" did
 249   not work well.
 250
 251 * Upcoming OpenSSL 1.1.0 will break compilation b updating a few APIs
 252   we use in imap-send, which has been adjusted for the change.
 253   (merge 1245c74 ky/imap-send-openssl-1.1.0 later to maint).
 254
 255 * The socks5:// proxy support added back in 2.6.4 days was not aware
 256   that socks5h:// proxies behave differently.
 257
 258 * "git config" had a codepath that tried to pass a NULL to
 259   printf("%s"), which nobody seems to have noticed.
 260
 261 * On Cygwin, object creation uses the "create a temporary and then
 262   rename it to the final name" pattern, not "create a temporary,
 263   hardlink it to the final name and then unlink the temporary"
 264   pattern.
 265
 266   This is necessary to use Git on Windows shared directories, and is
 267   already enabled for the MinGW and plain Windows builds.  It also
 268   has been used in Cygwin packaged versions of Git for quite a while.
 269   See http://thread.gmane.org/gmane.comp.version-control.git/291853
 270
 271 * "merge-octopus" strategy did not ensure that the index is clean
 272   when merge begins.
 273
 274 * When "git merge" notices that the merge can be resolved purely at
 275   the tree level (without having to merge blobs) and the resulting
 276   tree happens to already exist in the object store, it forgot to
 277   update the index, which lead to an inconsistent state for later
 278   operations.
 279
 280 * "git submodule" reports the paths of submodules the command
 281   recurses into, but this was incorrect when the command was not run
 282   from the root level of the superproject.
 283   (merge 2ab5660 sb/submodule-path-misc-bugs later to maint).
 284
 285 * The "user.useConfigOnly" configuration variable makes it an error
 286   if users do not explicitly set user.name and user.email.  However,
 287   its check was not done early enough and allowed another error to
 288   trigger, reporting that the default value we guessed from the
 289   system setting was unusable.  This was a suboptimal end-user
 290   experience as we want the users to set user.name/user.email without
 291   relying on the auto-detection at all.
 292   (merge d3c06c1 da/user-useconfigonly later to maint).
 293
 294 * "git mv old new" did not adjust the path for a submodule that lives
 295   as a subdirectory inside old/ directory correctly.
 296   (merge a127331 sb/mv-submodule-fix later to maint).
 297
 298 * "git replace -e" did not honour "core.editor" configuration.
 299   (merge 36b1437 js/replace-edit-use-editor-configuration later to maint).
 300
 301 * "git push" from a corrupt repository that attempts to push a large
 302   number of refs deadlocked; the thread to relay rejection notices
 303   for these ref updates blocked on writing them to the main thread,
 304   after the main thread at the receiving end notices that the push
 305   failed and decides not to read these notices and return a failure.
 306   (merge c4b2751 jk/push-client-deadlock-fix later to maint).
 307
 308 * mmap emulation on Windows has been optimized and work better without
 309   consuming paging store when not needed.
 310   (merge d5425d1 js/win32-mmap later to maint).
 311
 312 * A question by "git send-email" to ask the identity of the sender
 313   has been updated.
 314   (merge 0d6b21e jd/send-email-to-whom later to maint).
 315
 316 * UI consistency improvements for "git mergetool".
 317   (merge cce076e nf/mergetool-prompt later to maint).
 318
 319 * Other minor clean-ups and documentation updates
 320   (merge 8b5a3e9 kn/for-each-tag-branch later to maint).
 321   (merge 9c60d9f sb/misc-cleanups later to maint).
 322   (merge 7a6a44c cc/apply later to maint).
 323   (merge 6594883 nd/remove-unused later to maint).
 324   (merge 0ff7410 sg/test-lib-simplify-expr-away later to maint).
 325   (merge 060e776 jk/fix-attribute-macro-in-2.5 later to maint).
 326   (merge d16df0c rt/string-list-lookup-cleanup later to maint).