* unsatisfiability is determined in a slightly different way now. It …

…no longer

  uses the SAT solver, but rather determines whether any specs have no
  candidates at all after running through get_reduced_index. This has been
  faster in benchmarks, but we welcome further data from your use cases about
  whether this was a good change.  (conda#8741)
* when using the --only-deps flag for the `install` command, conda now
  explicitly records those specs in your history. This primarily serves to
  reduce conda accidentally removing packages that you have actually requested.  (conda#8766)

* UnsatisfiableError messages are now grouped into categories and explained a bit better.  (conda#8741)
* --repodata-fn argument can be passed multiple times to have more fallback
  paths. `repodata_fns` conda config setting does the same thing, but saves you
  from needing to do it for every command invocation.  (conda#8741)

* fix channel flip-flopping that was happening when adding a channel other than earlier ones  (conda#8741)
* refactor flow control for multiple repodata files to not use exceptions  (conda#8741)
* force conda to use only old .tar.bz2 files if conda-build <3.18.3 is
  installed. Conda-build breaks when inspecting file contents, and this is fixed
  in conda-build 3.18.3 (conda#8741)
* use --force when using rsync to improve behavior with folders that may exist
  in the destination somehow. (conda#8750)
* handle EPERM errors when renaming, because MacOS lets you remove or create
  files, but not rename them. Thanks Apple. (conda#8755)
* fix conda removing packages installed via `install` with --only-deps flag when
  either `update` or `remove` commands are run. See behavior changes above.
  (conda#8766)

* @csosborn
* @jjhelmus
* @katietz
* @msarahan
* @rrigdon

* Base initial solver specs map on explicitly requested specs (new an…

…d historic) (conda#8689)

* Improve anonymization of automatic error reporting  (conda#8715)
* Add option to keep using .tar.bz2 files, in case new .conda isn't working for whatever reason  (conda#8723)

* fix parsing hyphenated PyPI specs (change hyphens in versions to .)  (conda#8688)
* fix PrefixRecord creation when file inputs are .conda files  (conda#8689)
* fix PrefixRecord creation for pip-installed packages  (conda#8689)
* fix progress bar stopping at 75% (no extract progress with new libarchive)  (conda#8689)
* preserve pre-4.7 download() interface in conda.exports  (conda#8698)
* virtual packages (such as cuda) are represented by leading double underscores
  by convention, to avoid confusion with existing single underscore packages
  that serve other purposes (conda#8738)

* The `--prune` flag no longer does anything. Pruning is implicitly the
  standard behavior now as a result of the initial solver specs coming from
  explicitly requested specs. Conda will remove packages that are not explicitly
  requested and are not required directly or indirectly by any explicitly
  installed package.

* Document removal of the `free` channel from defaults (conda#8682)
* Add reference to conda config --describe  (conda#8712)
* Add a tutorial for .condarc modification  (conda#8737)

* @alexhall
* @cjmartian
* @kalefranz
* @martinkou
* @msarahan
* @rrigdon
* @soapy1

* Implement support for "virtual" CUDA packages, to make conda consid…

…er the system-installed CUDA driver and act accordingly (conda#8267)

* Support and prefer new .conda file format where available  (conda#8265, conda#8639)
* Use comma-separated env names in prompt when stacking envs  (conda#8431)
* show valid choices in error messages for enums  (conda#8602)
* freeze already-installed packages when running `conda install` as a first attempt, to speed up the solve in existing envs.  Fall back to full solve as necessary  (conda#8260, conda#8626)
* add optimization criterion to prefer arch over noarch packages when otherwise equivalent  (conda#8267)
* Remove `free` channel from defaults collection.  Add `restore_free_channel` config parameter if you want to keep it.  (conda#8579)
* Improve unsatisfiable hints  (conda#8638)
* Add capability to use custom repodata filename, for smaller subsets of repodata  (conda#8670)
* Parallelize SubdirData readup  (conda#8670)
* Parallelize transacation verification and execution  (conda#8670)

* Fix PATH handling with deactivate.d scripts  (conda#8464)
* Fix usage of deprecated collections ABCs (#)
* fix tcsh/csh initialization block  (conda#8591)
* fix missing CWD display in powershell prompt  (conda#8596)
* `wrap_subprocess_call`: fallback to sh if no bash  (conda#8611)
* move `TemporaryDirectory` to avoid importing from `conda.compat`  (conda#8671)
* fix missing conda-package-handling dependency in dev/start  (conda#8624)
* fix `path_to_url` string index out of range error  (conda#8265)
* fix conda init for xonsh  (conda#8644)
* fix fish activation (conda#8645)
* improve error handling for read-only filesystems  (conda#8665, conda#8674)
* break out of minimization when bisection has nowhere to go  (conda#8672)
* Handle None values for link channel name gracefully  (conda#8680)

* @chrisburr
* @eternalphane
* @jjhelmus
* @kalefranz
* @mbargull
* @msarahan
* @rrigdon
* @scopatz
* @seibert
* @soapy1
* @nehaljwani
* @nh3
* @teake
* @yuvalreches

* export extra function in powershell Conda.psm1 script (fixes anacon…

…da powershell prompt) (conda#8570)

* @msarahan

* disable ``test_legacy_repodata`` on win-32 (missing dependencies) (c…

…onda#8540)

* Fix activation problems on windows with bash, powershell, and batch.  Improve tests. (conda#8550, conda#8564)
* pass -U flag to for pip dependencies in conda env when running "conda env update"  (conda#8542)
* rename ``conda.common.os`` to ``conda.common._os`` to avoid shadowing os built-in  (conda#8548)
* raise exception when pip subprocess fails with conda env  (conda#8562)
* fix installing recursive requirements.txt files in conda env specs with python 2.7  (conda#8562)
* Don't modify powershell prompt when "changeps1" setting in condarc is False  (conda#8465)

* @dennispg
* @jjhelmus
* @jpgill86
* @mingwandroid
* @msarahan
* @noahp

4.6.12 (2019-04-10)

Bug fixes
* Fix compat import warning (conda#8507)
* Adjust collections import to avoid deprecation warning (conda#8499)
* Fix bug in CLI tests (conda#8468)
* Disallow the number sign in environment names (conda#8521)
* Workaround issues with noarch on certain repositories (conda#8523)
* Fix activation on Windows when spaces are in path (conda#8503)
* Fix conda init profile modification for powershell (conda#8531)
* Point conda.bat to condabin (conda#8517)
* Fix various bugs in activation (conda#8520, conda#8528)

Docs improvements
* Fix links in README (conda#8482)
* Changelogs for 4.6.10 and 4.6.11 (conda#8502)

Contributors
@Bezier89
@duncanmmacleod
@ivigamberdiev
@javabrett
@jjhelmus
@katietz
@mingwandroid
@msarahan
@nehaljwani
@rrigdon

2019-04-04 4.6.11

* Fix python-3 only FileNotFoundError usage in initialize.py (conda#8470

)

* Fix more JSON encode errors for the _Null data type (conda#8471)
* Fix non-posix-compliant == in conda.sh (conda#8475, conda#8476)
* improve detection of pip dependency in environment.yml files to avoid warning message (conda#8478)
* fix condabin\conda.bat use of dp0, making PATH additions incorrect (conda#8480)
* init_fish_user: don't assume config file exists  (conda#8481)
* Fix for chcp output ending with . (conda#8484)

* Changelogs for 4.6.8, 4.6.9

* @duncanmmacleod
* @nehaljwani
* @ilango100
* @jjhelmus
* @mingwandroid
* @msarahan
* @rrigdon

* Improve CI for docs commits (conda#8387, conda#8401, conda#8417)

* Implement `conda init --reverse` to undo rc file and registry changes (conda#8400)
* Improve handling of unicode systems  (conda#8342, conda#8435)
* Force the "COMSPEC"  environment variable to always point to cmd.exe on windows.  This was an implicit assumption that was not always true.  (conda#8457, conda#8461)

* Add central C:/ProgramData/conda as a search path on Windows  (conda#8272)
* remove direct use of ruamel_yaml (prefer internal abstraction, yaml_load)  (conda#8392)
* Fix/improve `conda init` support for fish shell (conda#8437)
* Improve solver behavior in the presence of inconsistent environments (such as pip as a conda dependency of python, but also installed via pip itself) (conda#8444)
* Handle read-only filesystems for environments.txt (conda#8451, conda#8453)
* Fix conda env commands involving pip-installed dependencies being installed into incorrect locations  (conda#8435)

* updated cheatsheet  (conda#8402)
* updated color theme  (conda#8403)

* @blackgear
* @dhirschfeld
* @jakirkham
* @jjhelmus
* @katietz
* @mingwandroid
* @msarahan
* @nehaljwani
* @rrigdon
* @soapy1
* @spamlrot-tic

* detect when parser fails to parse arguments (conda#8328)

* separate post-link script running from package linking.  Do linking of all packages first, then run any post-link
  scripts after all packages are present.  Ideally, more forgiving in presence of cycles.  (conda#8350)
* quote path to temporary requirements files generated by conda env.  Fixes issues with spaces.  (conda#8352)
* improve some exception handling around checking for presence of folders in extraction of tarballs  (conda#8360)
* fix reporting of packages when channel name is None  (conda#8379)
* fix the post-creation helper message from "source activate" to "conda activate"  (conda#8370)
* Add safety checks for directory traversal exploits in tarfiles.  These may be disabled using the ``safety_checks``
  configuration parameter.  (conda#8374)

* document MKL DLL hell and new Python env vars to control DLL search behavior  (conda#8315)
* add github template for reporting speed issues  (conda#8344)
* add in better use of sphinx admonitions (notes, warnings) for better accentuation in docs  (conda#8348)
* improve skipping CI builds when only docs changes are involved  (conda#8336)

* @albertmichaelj
* @jjhelmus
* @matta9001
* @msarahan
* @rrigdon
* @soapy1
* @steffenvan