Download Latest Version 26.5.0 source code.tar.gz (25.8 MB)
Email in envelope

Get an email when there's a new version of Conda

Home / 26.5.0
Name Modified Size InfoDownloads / Week
Parent folder
conda-26.5.0.tar.gz 2026-05-15 25.8 MB
0
conda-26.5.0.tar.gz.sha256sum 2026-05-15 65 Bytes
0
26.5.0 source code.tar.gz 2026-05-15 25.8 MB
0
26.5.0 source code.zip 2026-05-15 26.8 MB
3 3 weekly downloads
README.md 2026-05-15 13.8 kB
0
Totals: 5 Items   78.5 MB 3

26.5.0 (2026-05-15)

Enhancements

  • Add parsing and storage support for conditional dependencies, optional dependency groups, and variant flags in MatchSpec expressions (introduced in [conda/ceps#164](https://github.com/conda/ceps/issues/164), [conda/ceps#165](https://github.com/conda/ceps/issues/165), and [conda/ceps#166](https://github.com/conda/ceps/issues/166)). (#15443)
  • Add --clobber flag to conda create, matching existing support in conda install and conda update. (#15584 via [#15801])
  • Display a Warning when exporting lockfiles from environments containing packages installed with pip, uv, or other 3rd party Python package managers. (#15581 via [#15838])
  • Speed up condarc search path expansion on every reset_context() by ~5x (~1.35 ms/call to ~0.27 ms/call on a 27-entry path), via cheaper custom_expandvars() and os.scandir()-based directory traversal in Configuration._expand_search_path(). (#15867)
  • Drop the ChannelType metaclass from conda.models.channel.Channel. Single-argument Channel(value) construction and MultiChannel dispatch have moved to Channel.__new__, and the per-value cache is now @functools.cache on Channel.from_value. (#15867)
  • Remove a redundant context.__init__() call in main_subshell(). The first initialization with pre_args was immediately repeated after the no_plugins check without any change in arguments. (#15867)
  • ContextStack now allocates a single slot on construction instead of three. Slots are still doubled on demand, so deep nesting works identically. Eliminates two unnecessary ContextStackObject allocations at import time. (#15867)
  • Resolve._get_reduced_index() no longer uses copy.deepcopy() to snapshot specs_by_name. A dict comprehension with slice copies (v[:]) is sufficient because MatchSpec objects are immutable. Removes the import copy from resolve.py. (#15867)
  • Defer heavy imports in notices/core.py and cli/main_env.py to reduce the module cost of loading individual subcommand modules. (#15867)
  • Add fast path for conda --version / conda -V that prints the version and exits without loading the argument parser, context, or plugin system. (#15867)
  • Replace f-string log calls with %-style lazy formatting across the codebase. String interpolation is now deferred until the log record is actually emitted. Enable the ruff G004 rule to enforce this going forward. (#15867)
  • context.category_map is now a @memoizedproperty. The large static dict was rebuilt on every access; it is now constructed once and cached for the lifetime of the Context instance. (#15867)
  • Hot-path regexes in conda/models/match_spec.py and conda/activate.py are now compiled once at module load time instead of on every call. Removes repeated re.compile() overhead from the MatchSpec parser and the shell activation path resolver. (#15867)
  • PrefixData._load_single_record() now reads the conda-meta JSON file with Path.read_bytes() + json.loads() instead of opening a text file handle and calling json.load(). For the small files typical of conda-meta records, a single read syscall followed by an in-memory parse is faster than the incremental read performed by json.load(). (#15867)
  • Add Ruff TID253 rule to ban module-level imports of requests on the startup path, preventing accidental re-introduction of heavy import chains (e.g. the A1 regression fixed in [#15866]). Files in conda/gateways/ and other non-startup-path locations that legitimately import requests are annotated with # noqa: TID253.
  • Port sharded repodata implementation from conda-libmamba-solver. (#15906)
  • Add conda_exception_observers plugin hook for observational callbacks on any exception conda encounters (filterable per observer via watch_for). (#15910)
  • Bump conda-incubator/setup-miniconda to v4.0.0 across .github/workflows/tests.yml. v4.0.0 ships the perf work tested in [#15741], including direct .condarc YAML writes, local isDefaultEnvironment resolution, parallelized Windows takeown, bulk-move pkg cleanup, and dropped HTML index scraping; the Node.js 24 runtime is the breaking change motivating the major bump. (#15923)
  • Add default-implemented available_platforms and env_for(platform) on EnvironmentSpecBase (EXPERIMENTAL) for multi-platform environment specifiers (conda-lock.yml, pixi.lock). (#15927)
  • conda env create / conda env update check context.subdir in spec.available_platforms before calling spec.env_for(context.subdir) and raise PlatformMismatchError with the platforms the file does cover and a conda export command that includes the current platform when the check fails. (#15927)
  • Environment.from_cli pre-flights every -f / --file argument and reports all files that do not cover context.subdir in a single PlatformMismatchError instead of stopping at the first mismatch. (#15927)
  • Add PlatformMismatchError (subclass of CondaValueError) so the wording stays consistent across conda env create, conda env update, and Environment.from_cli. (#15927)
  • Rewrite the help text for conda create, conda export, conda env create, and conda env export (already an alias of conda export) to make lockfile workflows discoverable. The epilog of each command now lists the available input/output formats grouped by category, driven dynamically by the installed environment specifier and exporter plugins. (#15960)
  • Add context.preview configuration parameter (via CONDA_PREVIEW env var or preview: in .condarc) and context.preview_enabled(value) method for opt-in feature previews. (#16010)
  • Sharded repodata: extract dependency names and package records from v3 repodata groups in shard_mentioned_packages and iter_records for compatible solvers. (#16067 via [#16078])
  • Add startup performance benchmarks (tests/cli/test_startup_benchmarks.py) to the CodSpeed benchmark suite, covering import cost, context initialization, parser generation, and module-count guardrails. (#15838)
  • Canonicalize deferred deprecation shims in conda.auxlib.logz and conda.common.serialize to use deprecated.constant(..., factory=...), avoiding eager imports of conda.common.serialize.json on cold paths. (#15926)
  • Add factory= kwarg to conda.deprecations.deprecated.constant as a mutually-exclusive alternative to positional value. When given, the callable is invoked (and the result cached) only on first access of the deprecated symbol. Enables deprecating symbols whose materialization would otherwise force heavy imports at registration time, without giving up the canonical deprecated.constant API.
  • Improve initialization time by using stdlib json instead of requests.compat.json in conda.common.serialize.json, avoiding many transitive imports. (#15838)

Bug fixes

  • Don't raise RemoveError if a missing conda dependency is not being installed or uninstalled by the current transaction; can happen when a conda dependency was installed with pip. (#14050)
  • Fix v3 MatchSpec parser regression where PyPI-style extras in constrains (e.g. dask[array]) crash the classic solver due to a regex anchor bug and a test-only dispatcher override. (#15443 via [#16095])
  • Run PowerShell reactivate after conda install, update, upgrade, remove, and uninstall so that activate.ps1 runs and environment variables set by packages (e.g. proj, GDAL) are available in the same session without manually deactivating and reactivating. (#15643 via [#15710])
  • Make conda.notices.cache.clear_cache() robust against transient Windows file locks. It now rewinds notices.cache's mtime instead of deleting the file (which could silently fail with PermissionError), and ignores OSError when removing per-channel response caches. This fixes flaky behavior of tests/cli/test_main_notices.py::test_notices_shown_after_previous_command_error on Windows. (#15796, [#15817], [#15839])
  • Require pluggy >=1.6.0 to ensure the HookImpl.wrapper attribute is available; older versions caused an AttributeError at runtime in the plugin manager. (#15862)
  • Fix Environment.extrapolate so the solver receives virtual packages for the target platform (e.g. __glibc on linux-*) instead of the host's. This unblocks multi-platform conda export of lockfiles when specs like python=3.13 are pinned. (#15919)
  • Fix Context._override to correctly restore ParameterLoader (and other non-data descriptor) attributes on exit. The previous implementation shadowed the descriptor in __dict__ permanently, causing later reset_context() calls to ignore env-var changes for the overridden parameter.
  • Update the conda activate/conda deactivate commands return a 0 exit code when run with the -h/--help flag. (#15826 via [#15958])
  • Make the windows (bat activator) recognize the -h/--help flags. (#15826 via [#15958])
  • Make the windows powershell activator recognize the -h/--help flags. (#15978)
  • When invalidating the channel notices cache, rewind notices.cache's mtime in integer nanoseconds (stat.st_mtime_ns + os.utime(ns=...)) and check expiry against time.time_ns() so the NOTICES_DECORATOR_DISPLAY_INTERVAL boundary check is not subject to float/FILETIME rounding on Windows. (#16003)
  • Fix test_get_index_no_platform_with_offline_cache failing on conda-forge CI by warming the repodata cache before testing offline reads. (#16041)
  • Ensure that reported conda anchor files report case matched paths on Windows. (#16052 via [#15983])
  • Fix conda doctor --fix package reinstall step (#15740 via [#16054])
  • Remove conda-pypi dependency from the conda recipe to prevent downstream CI breakages. (#16082)
  • Validate MatchSpec package names against CEP-26 rules, rejecting names with invalid characters or structure. (#16087)
  • Fix wheel package extension not found when conda-pypi URLs have a trailing sha256 hash. (#16088 via [#16089])
  • Update tests/cli/test_cli_install.py::test_emscripten_forge to use https://repo.prefix.dev/emscripten-forge-4x, the channel URL recommended by the emscripten-forge installation docs. The legacy https://repo.mamba.pm/emscripten-forge host has been unreachable, causing the integration test to fail on every CI run across all platforms.

Deprecations

  • Accidentally allowed and silently ignored package[version<1]-like MatchSpecs will be removed in 27.3. The square bracket syntax must always include key=value pairs. (#15443)
  • Mark --env-spec/--environment-specifier as pending deprecation in favor of --format (#15794 via [#15834])
  • Deprecate conda.models.channel.ChannelType. Channel is now a regular class; use the builtin type(Channel) if you need to inspect the metaclass. (#15867)
  • Mark the conda.instructions module as pending deprecation for removal in 27.3, as a follow-up to the removal of conda.plan. (#15874)
  • Mark conda.gateways.logging.initialize_std_loggers as pending deprecation to be removed in 27.3. (#15876)
  • Mark conda.stdout, conda.stderr, conda.stdoutlog, conda.stderrlog, and conda.stdout.verbose loggers as pending deprecation to be removed in 27.3. (#15876)
  • Define private symbols, modules (i.e. starts-with-underscore _) as not requiring deprecation. Library users should avoid these symbols. See deprecations.md (docs.conda.io). (#15977)

Docs

  • Start dev-oriented documentation for type hints and how we use them. (#15768)
  • Add tutorial and API reference for the new exception observer plugin hook. (#15910)
  • Document available_platforms and env_for on EnvironmentSpecBase. (#15927)
  • Add information on conda-lockfiles to Managing environments page. (#16086)
  • Document factory= kwarg on deprecated.constant in the deprecations dev-guide.

Other

  • Add type hints to conda.common.io. (#15773)
  • Provide better error messages for when an environment file is not detected. (#15718 via [#15793])
  • Provide better error messages for when too many plugins can read an environment files. (#15718 via [#15793])
  • Require conda-libmamba-solver >=26.4.0. (#15950)
  • Require conda-pypi >=0.8.0 in the conda recipe. (#15987)
  • Bump conda-libmamba-solver minimum version to >=26.4.1. (#16043)
  • Make the Linux integration jobs resilient to Azure-hosted Ubuntu apt mirror outages by switching to the canonical archive.ubuntu.com mirror and enabling apt retries (Acquire::Retries=3). Also install shells (ash, csh, fish, tcsh, zsh) non-interactively with --no-install-recommends to shrink the download footprint.

Contributors

Source: README.md, updated 2026-05-15