4.8.0rc0 (2019-11-04)

* retry downloads if they fail, controlled by `remote_max_retries` and `remote_backoff_factor` configuration values (conda#9318)
* redact authentication information in some URLs (conda#9341)
* add osx version virtual package , `__osx` (conda#9349)
* add glibc virtual package, `__glibc` (conda#9358)

* removeed references to MD5s from docs (conda#9247)
* Add docs on `CONDA_DLL_SEARCH_MODIFICATION_ENABLED` (conda#9286)
* document threads, spec history and configuration (conda#9327)
* more documentation on channels (conda#9335)
* document the .condarc search order (conda#9369)
* various minor documentation fixes (conda#9238, conda#9248, conda#9267, conda#9334, conda#9351, conda#9372, conda#9378, conda#9388, conda#9391, conda#9393)

* fix issues with xonsh activation on Windows (conda#8246)
* remove unsupported --lock argument from conda clean (conda#8310)
* do not add `sys_prefix_path` to failed activation or deactivation (conda#9282)
* fix csh setenv command (conda#9284)
* do not memorize `PackageRecord.combined_depends` (conda#9289)
* use `CONDA_INTERNAL_OLDPATH` rather than `OLDPATH` in activation script (conda#9303)
* fixes xonsh activation and tab completion (conda#9305)
* fix what channels are queried when context.offline is True (conda#9385)

* @analog-cbarber
* @andreasg123
* @beckermr
* @bryant1410
* @colinbrislawn
* @felker
* @forrestwaters
* @gabrielcnr
* @isuruf
* @jakirkham
* @jeremyjliu
* @jjhelmus
* @jooh
* @jpigla
* @marcelotrevisani
* @melund
* @mfansler
* @mingwandroid
* @msarahan
* @rrigdon
* @scopatz
* @soapy1
* @WillyChen123
* @xhochy

* add support for env file creation based on explicit specs in history (

conda#9093)

* detect prefix paths when -p nor -n not given  (conda#9135)
* Add config parameter to disable conflict finding (for faster time to errors)  (conda#9190)

* fix race condition with creation of repodata cache dir  (conda#9073)
* fix ProxyError expected arguments  (conda#9123)
* makedirs to initialize .conda folder when registering env - fixes permission errors with .conda folders not existing when package cache gets created (conda#9215)
* fix list duplicates errors in reading repodata/prefix data  (conda#9132)
* fix neutered specs not being recorded in history, leading to unsatisfiable environments later  (conda#9147)
* Standardize "conda env list" behavior between platforms  (conda#9166)
* add JSON output to conda env create/update  (conda#9204)
* speed up finding conflicting specs (speed regression in 4.7.11)  (conda#9218)

* @beenje
* @Bezier89
* @cjmartian
* @forrestwaters
* @jjhelmus
* @martin-raden
* @msarahan
* @nganani
* @rrigdon
* @soapy1
* @WesRoach
* @zheaton

* add config for control of number of threads. These can be set in co…

…ndarc or using environment variables. Names/default values are: `default_threads/None`, `repodata_threads/None`, `verify_threads/1`, `execute_threads/1` (conda#9044)

* fix repodata_fns from condarc not being respected (conda#8998)
* Fix handling of UpdateModifiers other than FREEZE_INSTALLED (conda#8999)
* Improve conflict finding graph traversal (conda#9006)
* Fix setuptools being removed due to conda run_constrains (conda#9014)
* Avoid calling find_conflicts until all retries are spent (conda#9015)
* refactor _conda_activate.bat in hopes of improving behavior in parallel environments (conda#9021)
* Add support for local version specs in PYPI installed packages (conda#9025)
* fix boto3 initialization race condition (conda#9037)
* Fix return condition in package_cache_data (conda#9039)
* utilize libarchive_enabled attribute provided by conda-package-handling to fall back to .tar.bz2 files only. (conda#9041, conda#9053)
* Fix menu creation on windows having race condition, leading to popups about python.exe not being found (conda#9044)
* Improve list error when egg-link leads to extra egg-infos (conda#9045)
* Fix incorrect RemoveError when operating on an env that has one of conda's deps, but is not the env in which the current conda in use resides (conda#9054)

* Document new package format better
* Document `conda init` command
* Document availability of RSS feed for CDN-backed channels that clone

* @Bezier89
* @forrestwaters
* @hajapy
* @ihnorton
* @matthewwardrop
* @msarahan
* @rogererens
* @rrigdon
* @soapy1

* fix merging of specs

* fix bugs in building of chains in prefix graph

* @msarahan

* fix Non records in comprehension

* fix potential keyerror in depth-first search
* fix PackageNotFound attribute error

* @jjhelmus
* @msarahan

* improve unsatisfiable messages - try to group and explain output be…

…tter. Remove lots of extraneous stuff that was showing up in 4.7.7 (conda#8910)

* preload openssl on windows to avoid library conflicts and missing library issues (conda#8949)

* fix handling of channels where more than one channel contains packages with similar name, subdir, version and build_number.  This was causing mysterious unsatisfiable errors for some users.  (conda#8938)
* reverse logic check in checking channel equality, because == is not reciprocal to != with py27 (no `__ne__`) (conda#8938)
* fix an infinite loop or otherwise large process with building the unsatisfiable info.  Improve the depth-first search implementation.  (conda#8941)
* streamline fallback paths to unfrozen solve in case frozen fails. (conda#8942)
* Environment activation output only shows `conda activate envname` now, instead of sometimes showing just `activate`.  (conda#8947)

* @forrestwaters
* @jjhelmus
* @katietz
* @msarahan
* @rrigdon
* @soapy1

* When an update command doesn't do anything because installed softwa…

…re conflicts with the update, information about the conflict is shown, rather than just saying "all requests are already satisfied" (conda#8899)

* fix missing package_type attr in finding virtual packages  (conda#8917)
* fix parallel operations of loading index to preserve channel ordering  (conda#8921, conda#8922)
* filter PrefixRecords out from PackageRecords when making a graph to show unsatisfiable deps.  Fixes comparison error between mismatched types.  (conda#8924)
* install entry points before running post-link scripts, because post link scripts may depend on entry points.  (conda#8925)

* @jjhelmus
* @msarahan
* @rrigdon
* @soapy1

* Improve cuda virtual package conflict messages to show the `__cuda`…

… virtual package as part of the conflict (conda#8834)

* add additional debugging info to Resolve.solve (conda#8895)

* deduplicate error messages being shown for post-link scripts.  Show captured stdout/stderr on failure  (conda#8833)
* fix the checkout step in the Windows dev env setup instructions (conda#8827)
* bail out early when implicit python pinning renders an explicit spec unsatisfiable (conda#8834)
* handle edge cases in pinned specs better (conda#8843)
* extract package again if url is None (conda#8868)
* update docs regarding indexing and subdirs (conda#8874)
* remove warning about conda-build needing an update that was bothering people (conda#8884)
* only add repodata fn into cache key when fn is not repodata.json (conda#8900)
* allow conda to be downgraded with an explicit spec (conda#8892)
* add target to specs from historic specs (conda#8901)
* improve message when solving with a repodata file before repodata.json fails (conda#8907)
* fix distutils usage for "which" functionality.  Fix inability to change python version in envs with noarch packages (conda#8909)
* fix anaconda metapackage being removed because history matching was too restrictive (conda#8911)
* make freezing less aggressive; add fallback to non-frozen solve (conda#8912)

* @forrestwaters
* @jjhelmus
* @mcopes73
* @msarahan
* @richardjgowers
* @rrigdon
* @soapy1
* @twinssbc

* improve wording in informational message when a particular `*_repod…

…ata.json` can't be found. No need for alarm. (conda#8808)

* restore tests being run on win-32 appveyor  (conda#8801)
* fix Dist class handling of .conda files  (conda#8816)
* fix strict channel priority handling when a package is unsatisfiable and thus not present in the collection  (conda#8819)
* handle JSONDecodeError better when package is corrupted at extract time  (conda#8820)

* @dhirschfeld
* @msarahan
* @rrigdon

* Revert to and improve the unsatisfiability determination from 4.7.2…

… that was reverted in 4.7.3. It's faster. (conda#8783)

* fix tcsh/csh init scripts  (conda#8792)

* clean up docs of run_command
* fix broken links
* update docs environment.yaml file to update conda-package-handling
* conda logo favicon
* update strict channel priority info
* noarch package content ported from conda-forge
* add info about conda-forge
* remove references to things as they were before conda 4.1.  That was a long time ago.  This is not a history book.

* @jjhelmus
* @msarahan
* @rrigdon
* @soapy1