Documentation / RelNotes / 2.9.0.txton commit Merge branch 'js/rebase-r-strategy' (917a319)
   1Git 2.9 Release Notes
   2=====================
   3
   4Backward compatibility notes
   5----------------------------
   6
   7The end-user facing Porcelain level commands in the "git diff" and
   8"git log" family by default enable the rename detection; you can still
   9use "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"git commit-tree" plumbing command required the user to always sign
  20its result when the user sets the commit.gpgsign configuration
  21variable, which was an ancient mistake, which this release corrects.
  22A script that drives commit-tree, if it relies on this mistake, now
  23needs to read commit.gpgsign and pass the -S option as necessary.
  24
  25
  26Updates since v2.8
  27------------------
  28
  29UI, Workflows & Features
  30
  31 * Comes with git-multimail 1.3.1 (in contrib/).
  32
  33 * The end-user facing commands like "git diff" and "git log"
  34   now enable the rename detection by default.
  35
  36 * The credential.helper configuration variable is cumulative and
  37   there is no good way to override it from the command line.  As
  38   a special case, giving an empty string as its value now serves
  39   as the signal to clear the values specified in various files.
  40
  41 * A new "interactive.diffFilter" configuration can be used to
  42   customize the diff shown in "git add -i" sessions.
  43
  44 * "git p4" now allows P4 author names to be mapped to Git author
  45   names.
  46
  47 * "git rebase -x" can be used without passing "-i" option.
  48
  49 * "git -c credential.<var>=<value> submodule" can now be used to
  50   propagate configuration variables related to credential helper
  51   down to the submodules.
  52
  53 * "git tag" can create an annotated tag without explicitly given an
  54   "-a" (or "-s") option (i.e. when a tag message is given).  A new
  55   configuration variable, tag.forceSignAnnotated, can be used to tell
  56   the command to create signed tag in such a situation.
  57
  58 * "git merge" used to allow merging two branches that have no common
  59   base by default, which led to a brand new history of an existing
  60   project created and then get pulled by an unsuspecting maintainer,
  61   which allowed an unnecessary parallel history merged into the
  62   existing project.  The command has been taught not to allow this by
  63   default, with an escape hatch "--allow-unrelated-histories" option
  64   to be used in a rare event that merges histories of two projects
  65   that started their lives independently.
  66
  67 * "git pull" has been taught to pass the "--allow-unrelated-histories"
  68   option to underlying "git merge".
  69
  70 * "git apply -v" learned to report paths in the patch that were
  71   skipped via --include/--exclude mechanism or being outside the
  72   current working directory.
  73
  74 * Shell completion (in contrib/) updates.
  75
  76 * The commit object name reported when "rebase -i" stops has been
  77   shortened.
  78
  79 * "git worktree add" can be given "--no-checkout" option to only
  80   create an empty worktree without checking out the files.
  81
  82 * "git mergetools" learned to drive ExamDiff.
  83
  84 * "git pull --rebase" learned "--[no-]autostash" option, so that
  85   the rebase.autostash configuration variable set to true can be
  86   overridden from the command line.
  87
  88 * When "git log" shows the log message indented by 4-spaces, the
  89   remainder of a line after a HT does not align in the way the author
  90   originally intended.  The command now expands tabs by default to help
  91   such a case, and allows the users to override it with a new option,
  92   "--no-expand-tabs".
  93
  94 * "git send-email" now uses a more readable timestamps when
  95   formulating a message ID.
  96
  97 * "git rerere" can encounter two or more files with the same conflict
  98   signature that have to be resolved in different ways, but there was
  99   no way to record these separate resolutions.
 100
 101 * "git p4" learned to record P4 jobs in Git commit that imports from
 102   the history in Perforce.
 103
 104 * "git describe --contains" often made a hard-to-justify choice of
 105   tag to name a given commit, because it tried to come up
 106   with a name with smallest number of hops from a tag, causing an old
 107   commit whose close descendant that is recently tagged were not
 108   described with respect to an old tag but with a newer tag.  It did
 109   not help that its computation of "hop" count was further tweaked to
 110   penalize being on a side branch of a merge.  The logic has been
 111   updated to favor using the tag with the oldest tagger date, which
 112   is a lot easier to explain to the end users: "We describe a commit
 113   in terms of the (chronologically) oldest tag that contains the
 114   commit."
 115
 116 * "git clone" learned the "--shallow-submodules" option.
 117
 118 * HTTP transport clients learned to throw extra HTTP headers at the
 119   server, specified via http.extraHeader configuration variable.
 120
 121 * The "--compaction-heuristic" option to "git diff" family of
 122   commands enables a heuristic to make the patch output more readable
 123   by using a blank line as a strong hint that the contents before and
 124   after it belong to logically separate units.  It is still
 125   experimental.
 126
 127 * A new configuration variable core.hooksPath allows customizing
 128   where the hook directory is.
 129
 130 * An earlier addition of "sanitize_submodule_env" with 14111fc4 (git:
 131   submodule honor -c credential.* from command line, 2016-02-29)
 132   turned out to be a convoluted no-op; implement what it wanted to do
 133   correctly, and stop filtering settings given via "git -c var=val".
 134
 135 * "git commit --dry-run" reported "No, no, you cannot commit." in one
 136   case where "git commit" would have allowed you to commit, and this
 137   improves it a little bit ("git commit --dry-run --short" still does
 138   not give you the correct answer, for example).  This is a stop-gap
 139   measure in that "commit --short --dry-run" still gives an incorrect
 140   result.
 141
 142 * The experimental "multiple worktree" feature gains more safety to
 143   forbid operations on a branch that is checked out or being actively
 144   worked on elsewhere, by noticing that e.g. it is being rebased.
 145
 146 * "git format-patch" learned a new "--base" option to record what
 147   (public, well-known) commit the original series was built on in
 148   its output.
 149
 150 * "git commit" learned to pay attention to the "commit.verbose"
 151   configuration variable and act as if the "--verbose" option
 152   was given from the command line.
 153
 154 * Updated documentation gives hints to GMail users with two-factor
 155   auth enabled that they need app-specific-password when using
 156   "git send-email".
 157
 158 * The manpage output of our documentation did not render well in
 159   terminal; typeset literals in bold by default to make them stand
 160   out more.
 161
 162 * The mark-up in the top-level README.md file has been updated to
 163   typeset CLI command names differently from the body text.
 164
 165
 166Performance, Internal Implementation, Development Support etc.
 167
 168 * The embedded args argv-array in the child process is used to build
 169   the command line to run pack-objects instead of using a separate
 170   array of strings.
 171
 172 * A test for tags has been restructured so that more parts of it can
 173   easily be run on a platform without a working GnuPG.
 174
 175 * The startup_info data, which records if we are working inside a
 176   repository (among other things), are now uniformly available to Git
 177   subcommand implementations, and Git avoids attempting to touch
 178   references when we are not in a repository.
 179
 180 * The command line argument parser for "receive-pack" has been
 181   rewritten to use parse-options.
 182
 183 * A major part of "git submodule update" has been ported to C to take
 184   advantage of the recently added framework to run download tasks in
 185   parallel.  Other updates to "git submodule" that move pieces of
 186   logic to C continues.
 187
 188 * Rename bunch of tests on "git clone" for better organization.
 189
 190 * The tests that involve running httpd leaked the system-wide
 191   configuration in /etc/gitconfig to the tested environment.
 192
 193 * Build updates for MSVC.
 194
 195 * The repository set-up sequence has been streamlined (the biggest
 196   change is that there is no longer git_config_early()), so that we
 197   do not attempt to look into refs/* when we know we do not have a
 198   Git repository.
 199
 200 * Code restructuring around the "refs" API to prepare for pluggable
 201   refs backends.
 202
 203 * Sources to many test helper binaries and the generated helpers
 204   have been moved to t/helper/ subdirectory to reduce clutter at the
 205   top level of the tree.
 206
 207 * Unify internal logic between "git tag -v" and "git verify-tag"
 208   commands by making one directly call into the other.
 209
 210 * "merge-recursive" strategy incorrectly checked if a path that is
 211   involved in its internal merge exists in the working tree.
 212
 213 * The test scripts for "git p4" (but not "git p4" implementation
 214   itself) has been updated so that they would work even on a system
 215   where the installed version of Python is python 3.
 216
 217 * As nobody maintains our in-tree git.spec.in and distros use their
 218   own spec file, we stopped pretending that we support "make rpm".
 219
 220 * Move from "unsigned char[20]" to "struct object_id" continues.
 221
 222 * The code for warning_errno/die_errno has been refactored and a new
 223   error_errno() reporting helper is introduced.
 224   (merge 1da045f nd/error-errno later to maint).
 225
 226 * Running tests with '-x' option to trace the individual command
 227   executions is a useful way to debug test scripts, but some tests
 228   that capture the standard error stream and check what the command
 229   said can be broken with the trace output mixed in.  When running
 230   our tests under "bash", however, we can redirect the trace output
 231   to another file descriptor to keep the standard error of programs
 232   being tested intact.
 233
 234 * t0040 had too many unnecessary repetitions in its test data.  Teach
 235   test-parse-options program so that a caller can tell what it
 236   expects in its output, so that these repetitions can be cleaned up.
 237
 238 * Add perf test for "rebase -i".
 239
 240 * Common mistakes when writing gitlink: in our documentation are
 241   found by "make check-docs".
 242
 243 * t9xxx series has been updated primarily for readability, while
 244   fixing small bugs in it.  A few scripted Porcelain commands have
 245   also been updated to fix possible bugs around their use of
 246   "test -z" and "test -n".
 247
 248 * CI test was taught to run git-svn tests.
 249
 250 * "git cat-file --batch-all" has been sped up, by taking advantage
 251   of the fact that it does not have to read a list of objects, in two
 252   ways.
 253
 254 * test updates to make it more readable and maintainable.
 255   (merge e6273f4 es/t1500-modernize later to maint).
 256
 257 * "make DEVELOPER=1" worked as expected; setting DEVELOPER=1 in
 258   config.mak didn't.
 259   (merge 51dd3e8 mm/makefile-developer-can-be-in-config-mak later to maint).
 260
 261 * The way how "submodule--helper list" signals unmatch error to its
 262   callers has been updated.
 263
 264 * A bash-ism "local" has been removed from "git submodule" scripted
 265   Porcelain.
 266
 267
 268Also contains various documentation updates and code clean-ups.
 269
 270
 271Fixes since v2.8
 272----------------
 273
 274Unless otherwise noted, all the fixes since v2.8 in the maintenance
 275track are contained in this release (see the maintenance releases'
 276notes for details).
 277
 278 * "git config --get-urlmatch", unlike other variants of the "git
 279   config --get" family, did not signal error with its exit status
 280   when there was no matching configuration.
 281
 282 * The "--local-env-vars" and "--resolve-git-dir" options of "git
 283   rev-parse" failed to work outside a repository when the command's
 284   option parsing was rewritten in 1.8.5 era.
 285
 286 * "git index-pack --keep[=<msg>] pack-$name.pack" simply did not work.
 287
 288 * Fetching of history by naming a commit object name directly didn't
 289   work across remote-curl transport.
 290
 291 * A small memory leak in an error codepath has been plugged in xdiff
 292   code.
 293
 294 * strbuf_getwholeline() did not NUL-terminate the buffer on certain
 295   corner cases in its error codepath.
 296
 297 * "git mergetool" did not work well with conflicts that both sides
 298   deleted.
 299
 300 * "git send-email" had trouble parsing alias file in mailrc format
 301   when lines in it had trailing whitespaces on them.
 302
 303 * When "git merge --squash" stopped due to conflict, the concluding
 304   "git commit" failed to read in the SQUASH_MSG that shows the log
 305   messages from all the squashed commits.
 306
 307 * "git merge FETCH_HEAD" dereferenced NULL pointer when merging
 308   nothing into an unborn history (which is arguably unusual usage,
 309   which perhaps was the reason why nobody noticed it).
 310
 311 * When "git worktree" feature is in use, "git branch -d" allowed
 312   deletion of a branch that is checked out in another worktree,
 313   which was wrong.
 314
 315 * When "git worktree" feature is in use, "git branch -m" renamed a
 316   branch that is checked out in another worktree without adjusting
 317   the HEAD symbolic ref for the worktree.
 318
 319 * "git diff -M" used to work better when two originally identical
 320   files A and B got renamed to X/A and X/B by pairing A to X/A and B
 321   to X/B, but this was broken in the 2.0 timeframe.
 322
 323 * "git send-pack --all <there>" was broken when its command line
 324   option parsing was written in the 2.6 timeframe.
 325
 326 * "git format-patch --help" showed `-s` and `--no-patch` as if these
 327   are valid options to the command.  We already hide `--patch` option
 328   from the documentation, because format-patch is about showing the
 329   diff, and the documentation now hides these options as well.
 330
 331 * When running "git blame $path" with unnormalized data in the index
 332   for the path, the data in the working tree was blamed, even though
 333   "git add" would not have changed what is already in the index, due
 334   to "safe crlf" that disables the line-end conversion.  It has been
 335   corrected.
 336
 337 * A change back in version 2.7 to "git branch" broke display of a
 338   symbolic ref in a non-standard place in the refs/ hierarchy (we
 339   expect symbolic refs to appear in refs/remotes/*/HEAD to point at
 340   the primary branch the remote has, and as .git/HEAD to point at the
 341   branch we locally checked out).
 342
 343 * A partial rewrite of "git submodule" in the 2.7 timeframe changed
 344   the way the gitdir: pointer in the submodules point at the real
 345   repository location to use absolute paths by accident.  This has
 346   been corrected.
 347
 348 * "git commit" misbehaved in a few minor ways when an empty message
 349   is given via -m '', all of which has been corrected.
 350
 351 * Support for CRAM-MD5 authentication method in "git imap-send" did
 352   not work well.
 353
 354 * Upcoming OpenSSL 1.1.0 will break compilation by updating a few API
 355   elements we use in imap-send, which has been adjusted for the change.
 356
 357 * The socks5:// proxy support added back in 2.6.4 days was not aware
 358   that socks5h:// proxies behave differently from socks5:// proxies.
 359
 360 * "git config" had a codepath that tried to pass a NULL to
 361   printf("%s"), which nobody seems to have noticed.
 362
 363 * On Cygwin, object creation uses the "create a temporary and then
 364   rename it to the final name" pattern, not "create a temporary,
 365   hardlink it to the final name and then unlink the temporary"
 366   pattern.
 367
 368   This is necessary to use Git on Windows shared directories, and is
 369   already enabled for the MinGW and plain Windows builds.  It also
 370   has been used in Cygwin packaged versions of Git for quite a while.
 371   See http://thread.gmane.org/gmane.comp.version-control.git/291853
 372
 373 * "merge-octopus" strategy did not ensure that the index is clean
 374   when merge begins.
 375
 376 * When "git merge" notices that the merge can be resolved purely at
 377   the tree level (without having to merge blobs) and the resulting
 378   tree happens to already exist in the object store, it forgot to
 379   update the index, which left an inconsistent state that would
 380   break later operations.
 381
 382 * "git submodule" reports the paths of submodules the command
 383   recurses into, but these paths were incorrectly reported when
 384   the command was not run from the root level of the superproject.
 385
 386 * The "user.useConfigOnly" configuration variable makes it an error
 387   if users do not explicitly set user.name and user.email.  However,
 388   its check was not done early enough and allowed another error to
 389   trigger, reporting that the default value we guessed from the
 390   system setting was unusable.  This was a suboptimal end-user
 391   experience as we want the users to set user.name/user.email without
 392   relying on the auto-detection at all.
 393
 394 * "git mv old new" did not adjust the path for a submodule that lives
 395   as a subdirectory inside old/ directory correctly.
 396
 397 * "git replace -e" did not honour "core.editor" configuration.
 398
 399 * "git push" from a corrupt repository that attempts to push a large
 400   number of refs deadlocked; the thread to relay rejection notices
 401   for these ref updates blocked on writing them to the main thread,
 402   after the main thread at the receiving end notices that the push
 403   failed and decides not to read these notices and return a failure.
 404
 405 * mmap emulation on Windows has been optimized and work better without
 406   consuming paging store when not needed.
 407
 408 * A question by "git send-email" to ask the identity of the sender
 409   has been updated.
 410
 411 * UI consistency improvements for "git mergetool".
 412
 413 * "git rebase -m" could be asked to rebase an entire branch starting
 414   from the root, but failed by assuming that there always is a parent
 415   commit to the first commit on the branch.
 416
 417 * Fix a broken "p4 lfs" test.
 418
 419 * Recent update to Git LFS broke "git p4" by changing the output from
 420   its "lfs pointer" subcommand.
 421
 422 * "git fetch" test t5510 was flaky while running a (forced) automagic
 423   garbage collection.
 424
 425 * Documentation updates to help contributors setting up Travis CI
 426   test for their patches.
 427
 428 * Some multi-byte encoding can have a backslash byte as a later part
 429   of one letter, which would confuse "highlight" filter used in
 430   gitweb.
 431
 432 * "git commit-tree" plumbing command required the user to always sign
 433   its result when the user sets the commit.gpgsign configuration
 434   variable, which was an ancient mistake.  Rework "git rebase" that
 435   relied on this mistake so that it reads commit.gpgsign and pass (or
 436   not pass) the -S option to "git commit-tree" to keep the end-user
 437   expectation the same, while teaching "git commit-tree" to ignore
 438   the configuration variable.  This will stop requiring the users to
 439   sign commit objects used internally as an implementation detail of
 440   "git stash".
 441
 442 * "http.cookieFile" configuration variable clearly wants a pathname,
 443   but we forgot to treat it as such by e.g. applying tilde expansion.
 444
 445 * Consolidate description of tilde-expansion that is done to
 446   configuration variables that take pathname to a single place.
 447
 448 * Correct faulty recommendation to use "git submodule deinit ." when
 449   de-initialising all submodules, which would result in a strange
 450   error message in a pathological corner case.
 451
 452 * Many 'linkgit:<git documentation page>' references were broken,
 453   which are all fixed with this.
 454
 455 * "git rerere" can get confused by conflict markers deliberately left
 456   by the inner merge step, because they are indistinguishable from
 457   the real conflict markers left by the outermost merge which are
 458   what the end user and "rerere" need to look at.  This was fixed by
 459   making the conflict markers left by the inner merges a bit longer.
 460   (merge 0f9fd5c jc/ll-merge-internal later to maint).
 461
 462 * CI test was taught to build documentation pages.
 463
 464 * "git fsck" learned to catch NUL byte in a commit object as
 465   potential error and warn.
 466
 467 * Portability enhancement for "rebase -i" to help platforms whose
 468   shell does not like "for i in <empty>" (which is not POSIX-kosher).
 469
 470 * On Windows, .git and optionally any files whose name starts with a
 471   dot are now marked as hidden, with a core.hideDotFiles knob to
 472   customize this behaviour.
 473
 474 * Documentation for "git merge --verify-signatures" has been updated
 475   to clarify that the signature of only the commit at the tip is
 476   verified.  Also the phrasing used for signature and key validity is
 477   adjusted to align with that used by OpenPGP.
 478
 479 * A couple of bugs around core.autocrlf have been fixed.
 480
 481 * Many commands normalize command line arguments from NFD to NFC
 482   variant of UTF-8 on OSX, but commands in the "diff" family did
 483   not, causing "git diff $path" to complain that no such path is
 484   known to Git.  They have been taught to do the normalization.
 485
 486 * "git difftool" learned to handle unmerged paths correctly in
 487   dir-diff mode.
 488
 489 * The "are we talking with TTY, doing an interactive session?"
 490   detection has been updated to work better for "Git for Windows".
 491
 492 * We forgot to add "git log --decorate=auto" to documentation when we
 493   added the feature back in v2.1.0 timeframe.
 494   (merge 462cbb4 rj/log-decorate-auto later to maint).
 495
 496 * "git fast-import --export-marks" would overwrite the existing marks
 497   file even when it makes a dump from its custom die routine.
 498   Prevent it from doing so when we have an import-marks file but
 499   haven't finished reading it.
 500   (merge f4beed6 fc/fast-import-broken-marks-file later to maint).
 501
 502 * "git rebase -i", after it fails to auto-resolve the conflict, had
 503   an unnecessary call to "git rerere" from its very early days, which
 504   was spotted recently; the call has been removed.
 505   (merge 7063693 js/rebase-i-dedup-call-to-rerere later to maint).
 506
 507 * Other minor clean-ups and documentation updates
 508   (merge cd82b7a pa/cherry-pick-doc-typo later to maint).
 509   (merge 2bb73ae rs/patch-id-use-skip-prefix later to maint).
 510   (merge aa20cbc rs/apply-name-terminate later to maint).
 511   (merge fe17fc0 jc/t2300-setup later to maint).
 512   (merge e256eec jk/shell-portability later to maint).