RELEASE.txt

If you are reading this in the git repository, the contents
refer to *unreleased* changes since the last SCons release.
Past official release announcements appear at:

    https://scons.org/tag/releases.html

==================================================================

A new SCons release, X.Y.Z, is now available on the SCons download page:

    https://scons.org/pages/download.html

Here is a summary of the changes since 4.9.1:


NEW FUNCTIONALITY
-----------------

- List new features (presumably why a checkpoint is being released)

DEPRECATED FUNCTIONALITY
------------------------

- List anything that's been deprecated since the last release

CHANGED/ENHANCED EXISTING FUNCTIONALITY
---------------------------------------

- List modifications to existing features, where the previous behavior
  wouldn't actually be considered a bug

- Nodes are now treated as PathLike objects.

- Replace use of old conditional expression idioms with the official
  one from PEP 308 introduced in Python 2.5 (2006). The idiom being
  replaced (using and/or) is regarded as error prone.

- MSVC: The following shell environment variables are now included in
  the environment used by SCons to initialize MSVC when defined:
  VCPKG_DISABLE_METRICS, VCPKG_ROOT, POWERSHELL_TELEMETRY_OPTOUT,
  PSDisableModuleAnalysisCacheCleanup, and PSModuleAnalysisCachePath.
  A subset of the shell environment PSModulePath is included in the
  environment used by SCons to initialize MSVC when defined.  None of
  these variables and values are propagated to the user's SCons
  environment after running the MSVC batch files.

FIXES
-----

- Fixed SCons.Variables.PackageVariable to correctly test the default
  setting against both enable & disable strings. (Fixes #4702)

- MSVC: Fixed a significant delay experienced in the Github Actions
  windows 2022 and 2025 runners due to the environment used by SCons
  to initialize MSVC when the Visual Studio vcpkg component is
  installed. The Github Actions windows 2019 runner was not affected.

- Fix the variant dir component being missing from generated source file
  paths with CompilationDatabase() builder (Fixes #4003).

- Ninja tool generate_command() fixed to call subst() with correct
  arguments in ListAction case. Unit tests added for generate_command.

- Fix the SCons.Scanner.LaTeX to mimic LaTeX's search method.

- Ninja tool now quotes targets (if necessary) when calling back to
  SCons - both in the POST request constructed to contact the
  daemon, and in the command eventually issued from the deamon.

- Ninja tool is adjusted to recognize and emit the right rule in
  the case of special actions that the tool recognizes, like Copy.
  This was working in the case of single commands, but not when part
  of a list of actions. Recognition only happens if the special
  action is first in the list.

- Fix a test problem on Windows where UNC tests failed due to incorrect path
  munging if a non-default %TEMP% was defined (as in moving to a Dev Drive).

- Fix Issue #4746. The TEMPFILE is written in utf-8 encoding by default.
  If the tempfile contents cannot be decoded by the command the
  tempfile is passed to, (new) TEMPPFILEENCODING can be used to speficy a
  different encoding to use. On Windows, the username may be a cause of this,
  as the default path for temporary files includes the username. Setting
  (existing) TEMPFILEDIR may also help in this case.

IMPROVEMENTS
------------

- List improvements that wouldn't be visible to the user in the
  documentation:  performance improvements (describe the circumstances
  under which they would be observed), or major code cleanups

- Virtualenv support module modernized: previously looked first for an
  unofficial approach from before venv support was made part of Python
  in 3.3; now looks for the official approach first. This in an internal
  detail, the API is unchanged.

- Add internal routines to maniplutate publicly visible argument and
  target lists. These interfaces are not part of the public API.

PACKAGING
---------

- List changes in the way SCons is packaged and/or released

- The generated roff (.1) manpages are now included in the
  scons-doc tarball that is built at part of the release process,
  in addition to the html and txt versions. For distribution
  packaging, the manpages can be extracted from here (downloadable
  from https://scons.org/doc/ using a a version-specific URL,
  e.g. https://scons.org/doc/4.9.1/scons-doc-4.9.1.tar.gz).

DOCUMENTATION
-------------

- List any significant changes to the documentation (not individual
  typo fixes, even if they're mentioned in src/CHANGES.txt to give
  the contributor credit)

- Clarify how pre/post actions on an alias work.

- Improve the description of PackageVariable.

- The "API Docs" build (Sphinx) configuration is improved, and
  SConsDoc and SConsExample are now included - their API is
  interesting to developers working on SCons (needed to write docs),
  even if not part of "The SCons API" itself.

- Missing documentation for the Virtualenv() function is added.
  Note that the User Guide previously described a negative outcome
  as returning None.  It is now explicit that the path is returned if
  running in a virtualenv, and an empty (falsy) string if not.

- Improve the wording of Configure methods.

DEVELOPMENT
-----------

- List visible changes in the way SCons is developed

- runtest.py once again finds "external" tests, such as the tests for
  tools in scons-contrib. An earlier rework had broken this.  Fixes #4699.

- Clean up C and C++ FLAGS tests. Tests which use a real compiler
  are now more clearly distinguished (-live.py suffix and docstring).

- Fix a couple of unit tests to not fail with Python 3.14. These involve
  expectations for bytecode strings and error message contents; there was
  no problem with SCons itself using 3.14.

- Move the GitHub workflow test runner files from the SCons root to
  the ci subdirectory of the testing directory.

- GitHub: Enable the interactive tests on windows.

- GitHub: Enable the packaging tar xz test on windows.

- GitHub: Exclude two ninja tests that consistently fail on MacOS in
  the experimental tests workflow.

- GitHub: Add a workflow file to test MSVC with optional environment
  variables.

- GitHub: Populate the MSVC cache before running the test suite for
  select windows workflow files.

- GitHub: Upload the failed_tests.log artifact on failure in select
  workflow files.

- GitHub: Change the runtest workflow to allow the python version to
  be specified with the OS version.

- Testing: Increase the default timeout from 20 seconds to 60 seconds
  in the testing framework wait_for method. The timeout was increased
  during isolated experiments of the interactive tests on windows.

- Testing: Update the packaging tar bz2 and xz tests on on Windows.
  The packaging tar bz2 and xz tests should be skipped on Windows 10
  and GitHub windows-2022. The packaging tar bz2 and xz tests should
  be run on Windows 11 and GitHub windows-2025.

- Ninja: Increase the number of generated source files in the
  iterative speedup test from 200 to 250.  Increasing the workload
  should reduce the likelihood that the ninja tests are slower.

Thanks to the following contributors listed below for their contributions to this release.
==========================================================================================
.. code-block:: text


    git shortlog --no-merges -ns 4.9.1..HEAD