2023 jul updates to vm ubuntu 2004 scripts (#523)

* Support negative-valued action parameters
by converting them in the Python helper code into a positive value
whose bit pattern is the 2's complement representation of the negative
value.

* Add new bash function used several times in install script
Also delete some old comments.  These changes help to make the script
have fewer diffs with the following script that it was derived from:
https://github.com/jafingerhut/p4-guide/blob/master/bin/install-p4dev-v6.sh

* Fix copy & paste mistake

vm-ubuntu-20.04/user-dev-bootstrap.sh

@@ -14,6 +14,19 @@ GRPC_COMMIT="tags/v1.43.2"
 #Get the number of cores to speed up the compilation process
 NUM_CORES=`grep -c ^processor /proc/cpuinfo`
 
+# Change this to a lower value if you do not like all this extra debug
+# output.  It is occasionally useful to debug why Python package
+# install files, or other files installed system-wide, are not going
+# to the places where one might hope.
+DEBUG_INSTALL=2
+
+debug_dump_many_install_files() {
+    local OUT_FNAME="$1"
+    if [ ${DEBUG_INSTALL} -ge 2 ]
+    then
+	find /usr/lib /usr/local $HOME/.local | sort > "${OUT_FNAME}"
+    fi
+}
 
 # The install steps for p4lang/PI and p4lang/behavioral-model end
 # up installing Python module code in the site-packages directory
@@ -93,7 +106,7 @@ move_usr_local_lib_python3_from_site_packages_to_dist_packages() {
     ls -lrt ${DST_DIR}
 }
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-1-before-protobuf.txt
+debug_dump_many_install_files $HOME/usr-local-1-before-protobuf.txt
 
 # --- Protobuf --- #
 git clone https://github.com/protocolbuffers/protobuf
@@ -106,13 +119,9 @@ git submodule update --init --recursive
 make -j${NUM_CORES}
 sudo make install
 sudo ldconfig
-# Force install python module
-#cd python
-#sudo python3 setup.py install
-#cd ../..
 cd ..
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-2-after-protobuf.txt
+debug_dump_many_install_files $HOME/usr-local-2-after-protobuf.txt
 
 # --- gRPC --- #
 git clone https://github.com/grpc/grpc.git
@@ -124,18 +133,25 @@ cd cmake/build
 cmake ../..
 make -j${NUM_CORES}
 sudo make install
-# I believe the following 2 commands, adapted from similar commands in
+# I believe the following 2 'pip3 install ...' commands, adapted from
-# src/python/grpcio/README.rst, should install the Python3 module
+# similar commands in src/python/grpcio/README.rst, should install the
-# grpc.
+# Python3 module grpc.
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-2b-before-grpc-pip3.txt
+debug_dump_many_install_files $HOME/usr-local-2b-before-grpc-pip3.txt
 pip3 list | tee $HOME/pip3-list-2b-before-grpc-pip3.txt
 cd ../..
+# Before some time in 2023-July, the `sudo pip3 install
+# -rrequirements.txt` command below installed the Cython package
+# version 0.29.35.  After that time, it started installing Cython
+# package version 3.0.0, which gives errors on the `sudo pip3 install
+# .` command afterwards.  Fix this by forcing installation of a known
+# working version of Cython.
+sudo pip3 install Cython==0.29.35
 sudo pip3 install -rrequirements.txt
 GRPC_PYTHON_BUILD_WITH_CYTHON=1 sudo pip3 install .
 sudo ldconfig
 cd ..
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-3-after-grpc.txt
+debug_dump_many_install_files $HOME/usr-local-3-after-grpc.txt
 
 # Note: This is a noticeable difference between how an earlier
 # user-bootstrap.sh version worked, where it effectively ran
@@ -162,7 +178,7 @@ move_usr_local_lib_python3_from_site_packages_to_dist_packages
 sudo ldconfig
 cd ..
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-4-after-PI.txt
+debug_dump_many_install_files $HOME/usr-local-4-after-PI.txt
 
 # --- Bmv2 --- #
 git clone https://github.com/p4lang/behavioral-model.git
@@ -178,7 +194,7 @@ sudo ldconfig
 move_usr_local_lib_python3_from_site_packages_to_dist_packages
 cd ..
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-5-after-behavioral-model.txt
+debug_dump_many_install_files $HOME/usr-local-5-after-behavioral-model.txt
 
 # --- P4C --- #
 git clone https://github.com/p4lang/p4c
@@ -198,7 +214,7 @@ sudo make install
 sudo ldconfig
 cd ../..
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-6-after-p4c.txt
+debug_dump_many_install_files $HOME/usr-local-6-after-p4c.txt
 
 # --- PTF --- #
 git clone https://github.com/p4lang/ptf
@@ -207,4 +223,4 @@ git checkout ${PTF_COMMIT}
 sudo pip3 install .
 cd ..
 
-find /usr/lib /usr/local $HOME/.local | sort > $HOME/usr-local-8-after-ptf-install.txt
+debug_dump_many_install_files $HOME/usr-local-8-after-ptf-install.txt