sdh_store_and_pip_install_wheel: Install from the persistent wheel directory

[mkoeppe]

Python packages no longer use SAGE_DESTDIR except for staging/removing the .whl file.

This last bit of staging leads to sage -pip freeze showing wheel URLs in temporary build locations:

$ ./sage -pip freeze
alabaster @ file:///Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/local/var/tmp/sage/build/alabaster-0.7.12/src
appdirs==1.4.4
appnope @ file:///Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/local/var/tmp/sage/build/appnope-0.1.0.p0/src
argon2-cffi==20.1.0
attrs @ file:///Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/local/var/tmp/sage/build/attrs-19.3.0/src
Babel @ file:///Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/local/var/tmp/sage/build/babel-2.6.0/src

(These locations are recorded in direct_url.json according to https://www.python.org/dev/peps/pep-0610/; see https://packaging.python.org/en/latest/specifications/direct-url/)

In this ticket, we remove the staging, writing the .whl file directly into SAGE_VENV/var/lib/sage/wheels. (Uninstallation of the .whl file will be done by adding to the spkg-piprm script.)

Thus, sage -pip freeze will show the actual file URLs of the stored wheels.

CC: @jhpalmieri @tobiasdiez

Component: build

Issue created by migration from https://trac.sagemath.org/ticket/30956

[mkoeppe]

comment:1

This will have to wait until we get rid of using DESTDIR for Python packages

[mkoeppe]

Description changed:

--- 
+++ 
@@ -10,4 +10,5 @@
 Babel @ file:///Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/local/var/tmp/sage/build/babel-2.6.0/src
 ```
 
+(These locations are recorded in `direct_url.json` according to https://www.python.org/dev/peps/pep-0610/; see https://packaging.python.org/en/latest/specifications/direct-url/)
 

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,4 +1,6 @@
-This is so that `sage -pip freeze` shows the wheels in their persistent directory rather than the temporary build locations:
+Python packages no longer use SAGE_DESTDIR except for staging/removing the `.whl` file.
+
+This last bit of staging leads to `sage -pip freeze` showing wheel URLs in temporary build locations:
 
 ```
 $ ./sage -pip freeze
@@ -12,3 +14,6 @@
 
 (These locations are recorded in `direct_url.json` according to https://www.python.org/dev/peps/pep-0610/; see https://packaging.python.org/en/latest/specifications/direct-url/)
 
+
+In this ticket, we remove the staging, writing the `.whl` file directly into `SAGE_VENV/var/lib/sage/wheels`. Thus, `sage -pip freeze` will show the actual file URLs of the stored wheels.
+

[mkoeppe]

Description changed:

--- 
+++ 
@@ -15,5 +15,7 @@
 (These locations are recorded in `direct_url.json` according to https://www.python.org/dev/peps/pep-0610/; see https://packaging.python.org/en/latest/specifications/direct-url/)
 
 
-In this ticket, we remove the staging, writing the `.whl` file directly into `SAGE_VENV/var/lib/sage/wheels`. Thus, `sage -pip freeze` will show the actual file URLs of the stored wheels.
+In this ticket, we remove the staging, writing the `.whl` file directly into `SAGE_VENV/var/lib/sage/wheels`. (Uninstallation of the `.whl` file will be done by adding to the `spkg-piprm` script.) 
 
+Thus, `sage -pip freeze` will show the actual file URLs of the stored wheels.
+