Prepare the 2.1.154 release. (#2300)

CHANGES.md

@@ -1,5 +1,37 @@
 # Release Notes
 
+## 2.1.154
+
+This release brings three new features:
+
+1.  When creating PEXes without specifying an explicit
+    `--python-shebang`, an appropriate shebang is chosen correctly in
+    more cases than previously and a warning is emitted when the shebang
+    chosen cannot be guaranteed to be correct. The common case this
+    helps select the appropriate shebang for is PEXes built using
+    `--platform` or `--complete-platform`.
+2.  PEXes can now be created with `--no-pre-install-wheels` to cut down
+    PEX build times with a tradeoff of roughly 10% greater boot overhead
+    upon the 1st execution of the PEX file. For PEXes with very large
+    dependency sets (machine learning provides common cases), the build
+    time savings can be dramatic.
+3.  PEXes can now be told to install dependencies at runtime on 1st
+    execution using parallel processes using `--max-install-jobs` at PEX
+    build time or by setting the `PEX_MAX_INSTALL_JOBS` environment
+    variable at runtime.
+
+The last two features come with complicated tradeoffs and are turned off
+by default as a result. If you think they might help some of your use
+cases, there is more detail in the command line help for
+`--no-pre-install-wheels` and `--max-install-jobs` as well as in the
+`pex --help-variables` output for `PEX_MAX_INSTALL_JOBS`. You can also
+find a detailed performance analysis in #2292 for the extreme cases of
+very small and very large PEXes. In the end though, experimenting is
+probably your best bet.
+
+* Use appropriate shebang for multi-platform PEXes. (#2296)
+* Add support for --no-pre-install-wheels and --max-install-jobs. (#2298)
+
 ## 2.1.153
 
 This release fixes Pex runtime `sys.path` scrubbing to do less work and

pex/version.py

@@ -1,4 +1,4 @@
 # Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-__version__ = "2.1.153"
+__version__ = "2.1.154"