tox.ini (local): Add environment variables to skip system package installs and other steps, add mechanism for a local interactive shell

[mkoeppe]

(from #31064)

We add the following to the local-... environments:

• an environment variable that can be passed to tox to skip system package installs, directly reusing a previously set up system

SKIP_SYSTEM_PKG_INSTALL=yes tox -e local-homebrew-macos-standard -- config.status
SKIP_SYSTEM_PKG_INSTALL=yes tox -e local-homebrew-macos-standard -- config.status

This can save time and also give developers more control for experiments with system packages.

• a target that gives an interactive shell in the tox environment:

tox -e local-homebrew-macos-standard -- bash
tox -e local-direct -- bash
SKIP_SYSTEM_PKG_INSTALL=yes SKIP_BOOTSTRAP=1 SKIP_CONFIGURE=1 tox -e local-homebrew-macos-standard -- bash

Depends on #30944

CC: @tobiasdiez @kliem @dimpase

Component: porting

Author: Matthias Koeppe

Branch/Commit: 2d84b5a

Reviewer: Tobias Diez

Issue created by migration from https://trac.sagemath.org/ticket/31216

[mkoeppe]

Dependencies: #30944

[mkoeppe]

Branch: u/mkoeppe/tox_ini__local___add_environment_variables_to_skip_system_package_installs__mechanism_for_a_local_interactive_shell

[mkoeppe]

Commit: 13f58fc

[mkoeppe]

Description changed:

--- 
+++ 
@@ -6,6 +6,9 @@
 
   This can save time and also give developers more control for experiments with system packages.
 
-- a target or environment variable to give an interactive shell.
+- a target give an interactive shell:
 
-
+```
+tox -e local-homebrew-macos-standard -- bash
+tox -e local-direct -- bash
+```

[mkoeppe]

Last 10 new commits:

e5fe752	Merge tag '9.3.beta4' into t/30940/src_bin_sage_list_packages__make_it_work_if_sage_root_is_not_available
78ff9d5	src/sage/misc/package.py: Add one more # optional - build
a44042f	Merge branch 't/30940/src_bin_sage_list_packages__make_it_work_if_sage_root_is_not_available' into t/29124/script-packages-prereq-toolchain-bootstrap
64bde5f	Merge tag '9.3.beta5' into t/30940/src_bin_sage_list_packages__make_it_work_if_sage_root_is_not_available
e9a7572	src/sage/misc/package.py: Improve source formatting
c7bcda9	Merge branch 't/30940/src_bin_sage_list_packages__make_it_work_if_sage_root_is_not_available' into t/29124/script-packages-prereq-toolchain-bootstrap
9988c5f	ci-cygwin*.yml: Adjust to new script packages _bootstrap, _prereq
ab19133	Merge branch 't/29124/script-packages-prereq-toolchain-bootstrap' into t/30944/tox__improve_local_sudo_ubuntu_standard
c6ad06e	Merge branch 't/30944/tox__improve_local_sudo_ubuntu_standard' into t/31216/tox_ini__local___add_environment_variables_to_skip_system_package_installs__mechanism_for_a_local_interactive_shell
13f58fc	tox.ini (local): Run an interactive shell if posargs are bash

[mkoeppe]

Description changed:

--- 
+++ 
@@ -6,7 +6,7 @@
 
   This can save time and also give developers more control for experiments with system packages.
 
-- a target give an interactive shell:
+- a target that gives an interactive shell in the tox environment:
 
 ```
 tox -e local-homebrew-macos-standard -- bash

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

ace4ef6

tox.ini (local): Add option SKIP_SYSTEM_PKG_INSTALL=1

[sagetrac-git]

Changed commit from 13f58fc to ace4ef6

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

Description changed:

--- 
+++ 
@@ -4,6 +4,9 @@
 
 - an environment variable that can be passed to tox to skip system package installs, directly reusing a previously set up system
 
+```
+SKIP_SYSTEM_PKG_INSTALL=yes tox -e local-homebrew-macos-standard -- config.status
+```
   This can save time and also give developers more control for experiments with system packages.
 
 - a target that gives an interactive shell in the tox environment:
@@ -12,3 +15,4 @@
 tox -e local-homebrew-macos-standard -- bash
 tox -e local-direct -- bash
 ```
+

[tobiasdiez]

comment:8

On a first glance this looks good. Thanks! Could you please also add documentation for these tox commands / switches. Also I was wondering if one could add a tox -e local-homebrew-macos-standard -- install-system-packages that only installs the system packages?

[sagetrac-git]

Changed commit from ace4ef6 to ddc4f0b

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

ddc4f0b

tox.ini (local): Handle environment variables SKIP_BOOTSTRAP, SKIP_CONFIGURE

[mkoeppe]

Description changed:

--- 
+++ 
@@ -5,6 +5,7 @@
 - an environment variable that can be passed to tox to skip system package installs, directly reusing a previously set up system
 
 ```
+SKIP_SYSTEM_PKG_INSTALL=yes tox -e local-homebrew-macos-standard -- config.status
 SKIP_SYSTEM_PKG_INSTALL=yes tox -e local-homebrew-macos-standard -- config.status
 ```
   This can save time and also give developers more control for experiments with system packages.
@@ -14,5 +15,6 @@
 ```
 tox -e local-homebrew-macos-standard -- bash
 tox -e local-direct -- bash
+SKIP_SYSTEM_PKG_INSTALL=yes SKIP_BOOTSTRAP=1 SKIP_CONFIGURE=1 tox -e local-homebrew-macos-standard -- bash
 ```
 

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

bb6aec4	src/doc/en/developer/portability_testing.rst: Updates
6253bd8	src/doc/en/developer/portability_testing.rst: New section on SKIP_... environment variables