Documentation / RelNotes / 2.9.0.txton commit Merge branch 'jk/shell-portability' (45c0c21)
   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 * Patch output from "git diff" and friends has been tweaked to be
 122   more readable by using a blank line as a strong hint that the
 123   contents before and after it belong to logically separate units.
 124
 125 * A new configuration variable core.hooksPath allows customizing
 126   where the hook directory is.
 127
 128 * An earlier addition of "sanitize_submodule_env" with 14111fc4 (git:
 129   submodule honor -c credential.* from command line, 2016-02-29)
 130   turned out to be a convoluted no-op; implement what it wanted to do
 131   correctly, and stop filtering settings given via "git -c var=val".
 132
 133 * "git commit --dry-run" reported "No, no, you cannot commit." in one
 134   case where "git commit" would have allowed you to commit, and this
 135   improves it a little bit ("git commit --dry-run --short" still does
 136   not give you the correct answer, for example).  This is a stop-gap
 137   measure in that "commit --short --dry-run" still gives an incorrect
 138   result.
 139
 140 * The experimental "multiple worktree" feature gains more safety to
 141   forbid operations on a branch that is checked out or being actively
 142   worked on elsewhere, by noticing that e.g. it is being rebased.
 143
 144 * "git format-patch" learned a new "--base" option to record what
 145   (public, well-known) commit the original series was built on in
 146   its output.
 147
 148 * "git commit" learned to pay attention to the "commit.verbose"
 149   configuration variable and act as if the "--verbose" option
 150   was given from the command line.
 151
 152 * Updated documentation gives hints to GMail users with two-factor
 153   auth enabled that they need app-specific-password when using
 154   "git send-email".
 155
 156 * The manpage output of our documentation did not render well in
 157   terminal; typeset literals in bold by default to make them stand
 158   out more.
 159
 160 * The mark-up in the top-level README.md file has been updated to
 161   typeset CLI command names differently from the body text.
 162
 163
 164Performance, Internal Implementation, Development Support etc.
 165
 166 * The embedded args argv-array in the child process is used to build
 167   the command line to run pack-objects instead of using a separate
 168   array of strings.
 169
 170 * A test for tags has been restructured so that more parts of it can
 171   easily be run on a platform without a working GnuPG.
 172
 173 * The startup_info data, which records if we are working inside a
 174   repository (among other things), are now uniformly available to Git
 175   subcommand implementations, and Git avoids attempting to touch
 176   references when we are not in a repository.
 177
 178 * The command line argument parser for "receive-pack" has been
 179   rewritten to use parse-options.
 180
 181 * A major part of "git submodule update" has been ported to C to take
 182   advantage of the recently added framework to run download tasks in
 183   parallel.  Other updates to "git submodule" that move pieces of
 184   logic to C continues.
 185
 186 * Rename bunch of tests on "git clone" for better organization.
 187
 188 * The tests that involve running httpd leaked the system-wide
 189   configuration in /etc/gitconfig to the tested environment.
 190
 191 * Build updates for MSVC.
 192
 193 * The repository set-up sequence has been streamlined (the biggest
 194   change is that there is no longer git_config_early()), so that we
 195   do not attempt to look into refs/* when we know we do not have a
 196   Git repository.
 197
 198 * Code restructuring around the "refs" API to prepare for pluggable
 199   refs backends.
 200
 201 * Sources to many test helper binaries and the generated helpers
 202   have been moved to t/helper/ subdirectory to reduce clutter at the
 203   top level of the tree.
 204
 205 * Unify internal logic between "git tag -v" and "git verify-tag"
 206   commands by making one directly call into the other.
 207
 208 * "merge-recursive" strategy incorrectly checked if a path that is
 209   involved in its internal merge exists in the working tree.
 210
 211 * The test scripts for "git p4" (but not "git p4" implementation
 212   itself) has been updated so that they would work even on a system
 213   where the installed version of Python is python 3.
 214
 215 * As nobody maintains our in-tree git.spec.in and distros use their
 216   own spec file, we stopped pretending that we support "make rpm".
 217
 218 * Move from "unsigned char[20]" to "struct object_id" continues.
 219
 220 * The code for warning_errno/die_errno has been refactored and a new
 221   error_errno() reporting helper is introduced.
 222   (merge 1da045f nd/error-errno later to maint).
 223
 224 * Running tests with '-x' option to trace the individual command
 225   executions is a useful way to debug test scripts, but some tests
 226   that capture the standard error stream and check what the command
 227   said can be broken with the trace output mixed in.  When running
 228   our tests under "bash", however, we can redirect the trace output
 229   to another file descriptor to keep the standard error of programs
 230   being tested intact.
 231
 232 * t0040 had too many unnecessary repetitions in its test data.  Teach
 233   test-parse-options program so that a caller can tell what it
 234   expects in its output, so that these repetitions can be cleaned up.
 235
 236 * Add perf test for "rebase -i".
 237
 238 * Common mistakes when writing gitlink: in our documentation are
 239   found by "make check-docs".
 240
 241 * t9xxx series has been updated primarily for readability, while
 242   fixing small bugs in it.  A few scripted Porcelain commands have
 243   also been updated to fix possible bugs around their use of
 244   "test -z" and "test -n".
 245
 246 * CI test was taught to run git-svn tests.
 247
 248 * "git cat-file --batch-all" has been sped up, by taking advantage
 249   of the fact that it does not have to read a list of objects, in two
 250   ways.
 251
 252 * test updates to make it more readable and maintainable.
 253   (merge e6273f4 es/t1500-modernize later to maint).
 254
 255 * "make DEVELOPER=1" worked as expected; setting DEVELOPER=1 in
 256   config.mak didn't.
 257   (merge 51dd3e8 mm/makefile-developer-can-be-in-config-mak later to maint).
 258
 259 * The way how "submodule--helper list" signals unmatch error to its
 260   callers has been updated.
 261
 262 * A bash-ism "local" has been removed from "git submodule" scripted
 263   Porcelain.
 264
 265
 266Also contains various documentation updates and code clean-ups.
 267
 268
 269Fixes since v2.8
 270----------------
 271
 272Unless otherwise noted, all the fixes since v2.8 in the maintenance
 273track are contained in this release (see the maintenance releases'
 274notes for details).
 275
 276 * "git config --get-urlmatch", unlike other variants of the "git
 277   config --get" family, did not signal error with its exit status
 278   when there was no matching configuration.
 279
 280 * The "--local-env-vars" and "--resolve-git-dir" options of "git
 281   rev-parse" failed to work outside a repository when the command's
 282   option parsing was rewritten in 1.8.5 era.
 283
 284 * "git index-pack --keep[=<msg>] pack-$name.pack" simply did not work.
 285
 286 * Fetching of history by naming a commit object name directly didn't
 287   work across remote-curl transport.
 288
 289 * A small memory leak in an error codepath has been plugged in xdiff
 290   code.
 291
 292 * strbuf_getwholeline() did not NUL-terminate the buffer on certain
 293   corner cases in its error codepath.
 294
 295 * "git mergetool" did not work well with conflicts that both sides
 296   deleted.
 297
 298 * "git send-email" had trouble parsing alias file in mailrc format
 299   when lines in it had trailing whitespaces on them.
 300
 301 * When "git merge --squash" stopped due to conflict, the concluding
 302   "git commit" failed to read in the SQUASH_MSG that shows the log
 303   messages from all the squashed commits.
 304
 305 * "git merge FETCH_HEAD" dereferenced NULL pointer when merging
 306   nothing into an unborn history (which is arguably unusual usage,
 307   which perhaps was the reason why nobody noticed it).
 308
 309 * When "git worktree" feature is in use, "git branch -d" allowed
 310   deletion of a branch that is checked out in another worktree,
 311   which was wrong.
 312
 313 * When "git worktree" feature is in use, "git branch -m" renamed a
 314   branch that is checked out in another worktree without adjusting
 315   the HEAD symbolic ref for the worktree.
 316
 317 * "git diff -M" used to work better when two originally identical
 318   files A and B got renamed to X/A and X/B by pairing A to X/A and B
 319   to X/B, but this was broken in the 2.0 timeframe.
 320
 321 * "git send-pack --all <there>" was broken when its command line
 322   option parsing was written in the 2.6 timeframe.
 323
 324 * "git format-patch --help" showed `-s` and `--no-patch` as if these
 325   are valid options to the command.  We already hide `--patch` option
 326   from the documentation, because format-patch is about showing the
 327   diff, and the documentation now hides these options as well.
 328
 329 * When running "git blame $path" with unnormalized data in the index
 330   for the path, the data in the working tree was blamed, even though
 331   "git add" would not have changed what is already in the index, due
 332   to "safe crlf" that disables the line-end conversion.  It has been
 333   corrected.
 334
 335 * A change back in version 2.7 to "git branch" broke display of a
 336   symbolic ref in a non-standard place in the refs/ hierarchy (we
 337   expect symbolic refs to appear in refs/remotes/*/HEAD to point at
 338   the primary branch the remote has, and as .git/HEAD to point at the
 339   branch we locally checked out).
 340
 341 * A partial rewrite of "git submodule" in the 2.7 timeframe changed
 342   the way the gitdir: pointer in the submodules point at the real
 343   repository location to use absolute paths by accident.  This has
 344   been corrected.
 345
 346 * "git commit" misbehaved in a few minor ways when an empty message
 347   is given via -m '', all of which has been corrected.
 348
 349 * Support for CRAM-MD5 authentication method in "git imap-send" did
 350   not work well.
 351
 352 * Upcoming OpenSSL 1.1.0 will break compilation by updating a few API
 353   elements we use in imap-send, which has been adjusted for the change.
 354
 355 * The socks5:// proxy support added back in 2.6.4 days was not aware
 356   that socks5h:// proxies behave differently from socks5:// proxies.
 357
 358 * "git config" had a codepath that tried to pass a NULL to
 359   printf("%s"), which nobody seems to have noticed.
 360
 361 * On Cygwin, object creation uses the "create a temporary and then
 362   rename it to the final name" pattern, not "create a temporary,
 363   hardlink it to the final name and then unlink the temporary"
 364   pattern.
 365
 366   This is necessary to use Git on Windows shared directories, and is
 367   already enabled for the MinGW and plain Windows builds.  It also
 368   has been used in Cygwin packaged versions of Git for quite a while.
 369   See http://thread.gmane.org/gmane.comp.version-control.git/291853
 370
 371 * "merge-octopus" strategy did not ensure that the index is clean
 372   when merge begins.
 373
 374 * When "git merge" notices that the merge can be resolved purely at
 375   the tree level (without having to merge blobs) and the resulting
 376   tree happens to already exist in the object store, it forgot to
 377   update the index, which left an inconsistent state that would
 378   break later operations.
 379
 380 * "git submodule" reports the paths of submodules the command
 381   recurses into, but these paths were incorrectly reported when
 382   the command was not run from the root level of the superproject.
 383
 384 * The "user.useConfigOnly" configuration variable makes it an error
 385   if users do not explicitly set user.name and user.email.  However,
 386   its check was not done early enough and allowed another error to
 387   trigger, reporting that the default value we guessed from the
 388   system setting was unusable.  This was a suboptimal end-user
 389   experience as we want the users to set user.name/user.email without
 390   relying on the auto-detection at all.
 391
 392 * "git mv old new" did not adjust the path for a submodule that lives
 393   as a subdirectory inside old/ directory correctly.
 394
 395 * "git replace -e" did not honour "core.editor" configuration.
 396
 397 * "git push" from a corrupt repository that attempts to push a large
 398   number of refs deadlocked; the thread to relay rejection notices
 399   for these ref updates blocked on writing them to the main thread,
 400   after the main thread at the receiving end notices that the push
 401   failed and decides not to read these notices and return a failure.
 402
 403 * mmap emulation on Windows has been optimized and work better without
 404   consuming paging store when not needed.
 405
 406 * A question by "git send-email" to ask the identity of the sender
 407   has been updated.
 408
 409 * UI consistency improvements for "git mergetool".
 410
 411 * "git rebase -m" could be asked to rebase an entire branch starting
 412   from the root, but failed by assuming that there always is a parent
 413   commit to the first commit on the branch.
 414
 415 * Fix a broken "p4 lfs" test.
 416
 417 * Recent update to Git LFS broke "git p4" by changing the output from
 418   its "lfs pointer" subcommand.
 419
 420 * "git fetch" test t5510 was flaky while running a (forced) automagic
 421   garbage collection.
 422
 423 * Documentation updates to help contributors setting up Travis CI
 424   test for their patches.
 425
 426 * Some multi-byte encoding can have a backslash byte as a later part
 427   of one letter, which would confuse "highlight" filter used in
 428   gitweb.
 429
 430 * "git commit-tree" plumbing command required the user to always sign
 431   its result when the user sets the commit.gpgsign configuration
 432   variable, which was an ancient mistake.  Rework "git rebase" that
 433   relied on this mistake so that it reads commit.gpgsign and pass (or
 434   not pass) the -S option to "git commit-tree" to keep the end-user
 435   expectation the same, while teaching "git commit-tree" to ignore
 436   the configuration variable.  This will stop requiring the users to
 437   sign commit objects used internally as an implementation detail of
 438   "git stash".
 439
 440 * "http.cookieFile" configuration variable clearly wants a pathname,
 441   but we forgot to treat it as such by e.g. applying tilde expansion.
 442
 443 * Consolidate description of tilde-expansion that is done to
 444   configuration variables that take pathname to a single place.
 445
 446 * Correct faulty recommendation to use "git submodule deinit ." when
 447   de-initialising all submodules, which would result in a strange
 448   error message in a pathological corner case.
 449
 450 * Many 'linkgit:<git documentation page>' references were broken,
 451   which are all fixed with this.
 452
 453 * "git rerere" can get confused by conflict markers deliberately left
 454   by the inner merge step, because they are indistinguishable from
 455   the real conflict markers left by the outermost merge which are
 456   what the end user and "rerere" need to look at.  This was fixed by
 457   making the conflict markers left by the inner merges a bit longer.
 458   (merge 0f9fd5c jc/ll-merge-internal later to maint).
 459
 460 * CI test was taught to build documentation pages.
 461
 462 * "git fsck" learned to catch NUL byte in a commit object as
 463   potential error and warn.
 464
 465 * Portability enhancement for "rebase -i" to help platforms whose
 466   shell does not like "for i in <empty>" (which is not POSIX-kosher).
 467
 468 * On Windows, .git and optionally any files whose name starts with a
 469   dot are now marked as hidden, with a core.hideDotFiles knob to
 470   customize this behaviour.
 471
 472 * Documentation for "git merge --verify-signatures" has been updated
 473   to clarify that the signature of only the commit at the tip is
 474   verified.  Also the phrasing used for signature and key validity is
 475   adjusted to align with that used by OpenPGP.
 476
 477 * A couple of bugs around core.autocrlf have been fixed.
 478
 479 * Many commands normalize command line arguments from NFD to NFC
 480   variant of UTF-8 on OSX, but commands in the "diff" family did
 481   not, causing "git diff $path" to complain that no such path is
 482   known to Git.  They have been taught to do the normalization.
 483
 484 * "git difftool" learned to handle unmerged paths correctly in
 485   dir-diff mode.
 486
 487 * The "are we talking with TTY, doing an interactive session?"
 488   detection has been updated to work better for "Git for Windows".
 489
 490 * We forgot to add "git log --decorate=auto" to documentation when we
 491   added the feature back in v2.1.0 timeframe.
 492   (merge 462cbb4 rj/log-decorate-auto later to maint).
 493
 494 * "git fast-import --export-marks" would overwrite the existing marks
 495   file even when it makes a dump from its custom die routine.
 496   Prevent it from doing so when we have an import-marks file but
 497   haven't finished reading it.
 498   (merge f4beed6 fc/fast-import-broken-marks-file later to maint).
 499
 500 * "git rebase -i", after it fails to auto-resolve the conflict, had
 501   an unnecessary call to "git rerere" from its very early days, which
 502   was spotted recently; the call has been removed.
 503   (merge 7063693 js/rebase-i-dedup-call-to-rerere later to maint).
 504
 505 * Other minor clean-ups and documentation updates
 506   (merge cd82b7a pa/cherry-pick-doc-typo later to maint).
 507   (merge 2bb73ae rs/patch-id-use-skip-prefix later to maint).
 508   (merge aa20cbc rs/apply-name-terminate later to maint).