48

I saw on this page that pip install neo4j-doc-manager --pre was used. What does the --pre flag mean?

Ali
  • 2,228
  • 1
  • 21
  • 21

2 Answers2

46

It tells pip to include pre-release versions of packages when searching for the latest version.

From the pip install reference documentation:

Include pre-release and development versions. By default, pip only finds stable versions.

See the section on Pre-release Versions:

Starting with v1.4, pip will only install stable versions as specified by PEP426 by default. If a version cannot be parsed as a compliant PEP426 version then it is assumed to be a pre-release.

The neo4j-doc-manager package currently has 5 releases out; one 'stable' 0.1.0 release and 4 devX releases which are newer, see the machine-readable list of releases. Without the --pre switch the 0.1.0 release would be installed, with the switch (as of this writing) 1.0.0.dev11 would be installed instead.

Marcel Gosselin
  • 4,610
  • 2
  • 31
  • 54
Martijn Pieters
  • 1,048,767
  • 296
  • 4,058
  • 3,343
  • Why would anyone wants to install with --pre option when there is a stable release by default? Thanks – Nguai al Dec 07 '21 at 16:33
  • 3
    To get or test a feature that is no yet available in the stable version. – Paul Rougieux Dec 15 '21 at 15:24
  • 1
    Or to be able to use a prerelease that supports newer versions of a dependency. Can be relevant for security issues, such as here. https://github.com/jupyter/nbconvert/issues/1685#issuecomment-1201280098 – ketil Feb 14 '23 at 13:49
6

The pip install command also supports a --pre flag that will enable installing pre-releases and development releases.

Source.

Community
  • 1
  • 1
alex
  • 479,566
  • 201
  • 878
  • 984