Trac #32406: Make "./configure --enable-editable" the default

This has been available since 9.3, has been improved in 9.4 and in the
9.7 series (#33855), and is ready for general consumption

Introduction:
- https://wiki.sagemath.org/ReleaseTours/sage-9.3#Editable_.28.22in-
place.22.2C_.22develop.22.29_installs_of_the_Sage_library

Discussion:
- https://groups.google.com/g/sage-devel/c/0GV8_O1VwbI

URL: https://trac.sagemath.org/32406
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): John Palmieri

Author: Release Manager

README.md

@@ -304,6 +304,11 @@ in the Installation Guide.
       where `SAGE_LOCAL` is the desired installation prefix, which
       must be writable by the user.
 
+      If you use this option in combination with `--disable-editable`,
+      you can delete the entire Sage source tree after completing
+      the build process.  What is installed in `SAGE_LOCAL` will be
+      a self-contained installation of Sage.
+
     - Note that in Sage's build process, `make` builds **and**
       installs (`make install` is a no-op).  Therefore the
       installation hierarchy must be writable by the user.
@@ -321,19 +326,7 @@ in the Installation Guide.
 
         $ ./configure --help
 
-    Some notable options for Sage developers are the following:
-
-    - Use `./configure --enable-editable` to configure the Sage distribution
-      to install the Sage library in "develop" ("editable", "in-place") mode
-      instead of using the Sage library's custom incremental build system.
-
-      It has the benefit that to try out changes to Python files, one does not
-      need to run `./sage -b` any more; restarting Sage is enough. It may also
-      have benefits in certain develop environments that get confused by
-      sagelib's custom build system.
-
-      Note that in an editable install, the source directory will be cluttered
-      with build artifacts (but they are `.gitignored`). This is normal.
+    A notable option for Sage developers is the following:
 
     - Use `./configure --enable-download-from-upstream-url` to allow
       downloading packages from their upstream URL if they cannot (yet) be

configure.ac

@@ -127,8 +127,9 @@ AC_ARG_ENABLE([debug],
 AC_ARG_VAR(SAGE_DEBUG, controls debugging support: "no" debugging; debugging "symbols" (default); build debug version ("yes"))
 
 AC_ARG_ENABLE([editable],
-              [AS_HELP_STRING([--enable-editable],
-                              [use an editable install of the Sage library])],
+              [AS_HELP_STRING([--disable-editable],
+                              [do not use an editable install of the Sage library: changes to Python files will require "sage -b" to rebuild the Sage library])],
+              [AC_SUBST([SAGE_EDITABLE], [$enableval])],
               [AC_SUBST([SAGE_EDITABLE], [yes])])
 
 # Check whether we are on a supported platform

docker/Dockerfile

@@ -168,7 +168,8 @@ ENV MAKEFLAGS $MAKEFLAGS
 ARG SAGE_NUM_THREADS="2"
 ENV SAGE_NUM_THREADS $SAGE_NUM_THREADS
 RUN make configure
-RUN ./configure
+# Old default before https://trac.sagemath.org/ticket/32406
+RUN ./configure --disable-editable
 RUN make build
 
 ################################################################################

src/MANIFEST.in

@@ -7,3 +7,5 @@ prune .tox
 
 prune sage/ext/interpreters   # In particular, __init__.py must not be present in the distribution; or sage_setup.autogen.interpreters.rebuild will not generate the code
 prune sage_setup
+prune sage_docbuild
+prune doc

src/setup.py

@@ -50,7 +50,7 @@
 # ## Configuration
 # ########################################################
 
-if len(sys.argv) > 1 and (sys.argv[1] == "sdist" or sys.argv[1] == "egg_info"):
+if len(sys.argv) > 1 and (sys.argv[1] in ["sdist", "egg_info", "dist_info"]):
     sdist = True
 else:
     sdist = False