as expected, the last buid failed when buildozer called package_app.py and it tried to have pip install python3.

  2020-06-22T09:24:53.7558430Z + buildozer osx debug
  2020-06-22T09:24:59.5810690Z [0m[1;34m# Check configuration tokens[0m
  2020-06-22T09:24:59.5811420Z [0m[1;34m# Ensure build layout[0m
  2020-06-22T09:24:59.5811900Z [0m[1;34m# Check configuration tokens[0m
  2020-06-22T09:24:59.5812370Z [0m[1;34m# Preparing build[0m
  2020-06-22T09:24:59.5812840Z [0m[1;34m# Check requirements for osx[0m
  2020-06-22T09:24:59.5813300Z [0m[1;34m# Check if kivy-sdk-packager exists[0m
  2020-06-22T09:24:59.5813890Z [0m[1;34m# kivy-sdk-packager found at /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/osx/platform[0m
  2020-06-22T09:24:59.5814390Z [0m[1;34m# check if Kivy.app exists in local dir[0m
  2020-06-22T09:24:59.5815000Z [0m[1;34m# Kivy.app found at /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/osx/platform/kivy-sdk-packager-master/osx[0m
  2020-06-22T09:24:59.5816160Z [0m[1;34m# Install platform[0m
  2020-06-22T09:24:59.5816650Z [0m[1;34m# Check application requirements[0m
  2020-06-22T09:24:59.5817250Z [0m[1;30m# Remove directory and subdirectory /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/applibs[0m
  2020-06-22T09:24:59.5817840Z [0m[1;30m# Create directory /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/applibs[0m
  2020-06-22T09:24:59.5818490Z [0m[1;30m# Run 'python3 -m venv ./venv'[0m
  2020-06-22T09:24:59.5819300Z [0m[1;30m# Cwd /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer[0m
  2020-06-22T09:24:59.5820030Z [0m[1;30m# Run 'bash -c "source venv/bin/activate && env"'[0m
  2020-06-22T09:24:59.5820850Z [0m[1;30m# Cwd /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer[0m
  2020-06-22T09:24:59.5821060Z GITHUB_JOB=mac
  2020-06-22T09:24:59.5821550Z GITHUB_EVENT_PATH=/Users/runner/runners/2.263.0/work/_temp/_github_workflow/event.json
  2020-06-22T09:24:59.5821770Z RUNNER_OS=macOS
  2020-06-22T09:24:59.5821930Z NVM_CD_FLAGS=
  2020-06-22T09:24:59.5822100Z ANDROID_HOME=/Users/runner/Library/Android/sdk
  2020-06-22T09:24:59.5822270Z GITHUB_BASE_REF=
  2020-06-22T09:24:59.5822440Z CHROMEWEBDRIVER=/usr/local/Caskroom/chromedriver/83.0.4103.39
  2020-06-22T09:24:59.5822620Z SHELL=/bin/bash
  2020-06-22T09:24:59.5822770Z TMPDIR=/var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T/
  2020-06-22T09:24:59.5822950Z GITHUB_REPOSITORY_OWNER=maltfield
  2020-06-22T09:24:59.5823440Z GITHUB_ACTIONS=true
  2020-06-22T09:24:59.5824420Z GITHUB_RUN_NUMBER=34
  2020-06-22T09:24:59.5824580Z __PYVENV_LAUNCHER__=/Applications/Xcode_11.5.app/Contents/Developer/usr/bin/python3
  2020-06-22T09:24:59.5824690Z RCT_NO_LAUNCH_PACKAGER=1
  2020-06-22T09:24:59.5826190Z JAVA_HOME_8_X64=/Library/Java/JavaVirtualMachines/zulu-8.jdk/Contents/Home
  2020-06-22T09:24:59.5827220Z RUNNER_WORKSPACE=/Users/runner/runners/2.263.0/work/cross-platform-python-gui
  2020-06-22T09:24:59.5827440Z RUNNER_PERFLOG=/usr/local/opt/runner/perflog
  2020-06-22T09:24:59.5827640Z NUNIT_BASE_PATH=/Library/Developer/nunit
  2020-06-22T09:24:59.5827840Z NUNIT3_PATH=/Library/Developer/nunit/3.6.0
  2020-06-22T09:24:59.5828680Z LC_ALL=en_US.UTF-8
  2020-06-22T09:24:59.5828900Z GITHUB_REF=refs/heads/master
  2020-06-22T09:24:59.5829080Z GITHUB_WORKFLOW=build
  2020-06-22T09:24:59.5830010Z JAVA_HOME_11_X64=/Library/Java/JavaVirtualMachines/zulu-11.jdk/Contents/Home
  2020-06-22T09:24:59.5830230Z RUNNER_TOOL_CACHE=/Users/runner/hostedtoolcache
  2020-06-22T09:24:59.5831160Z JAVA_HOME_14_X64=/Library/Java/JavaVirtualMachines/zulu-14.jdk/Contents/Home
  2020-06-22T09:24:59.5831390Z USER=runner
  2020-06-22T09:24:59.5831570Z NVM_DIR=/Users/runner/.nvm
  2020-06-22T09:24:59.5831780Z XCODE_10_DEVELOPER_DIR=/Applications/Xcode_10.3.app/Contents/Developer
  2020-06-22T09:24:59.5832000Z GITHUB_SHA=be7943fa2fe902ec8bdb0fd76d7d32a4052ea9b7
  2020-06-22T09:24:59.5832190Z GITHUB_EVENT_NAME=push
  2020-06-22T09:24:59.5832460Z GITHUB_API_URL=https://api.github.com
  2020-06-22T09:24:59.5832670Z RUNNER_TEMP=/Users/runner/runners/2.263.0/work/_temp
  2020-06-22T09:24:59.5832860Z ImageVersion=20200610.3
  2020-06-22T09:24:59.5833040Z SSH_AUTH_SOCK=/private/tmp/com.apple.launchd.biTD2JCey2/Listeners
  2020-06-22T09:24:59.5833240Z HOMEBREW_NO_AUTO_UPDATE=1
  2020-06-22T09:24:59.5833430Z __CF_USER_TEXT_ENCODING=0x1F5:0:0
  2020-06-22T09:24:59.5833650Z GITHUB_SERVER_URL=https://github.com
  2020-06-22T09:24:59.5833870Z AGENT_TOOLSDIRECTORY=/Users/runner/hostedtoolcache
  2020-06-22T09:24:59.5834040Z GITHUB_HEAD_REF=
  2020-06-22T09:24:59.5835320Z VIRTUAL_ENV=/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/venv
  2020-06-22T09:24:59.5835630Z GITHUB_GRAPHQL_URL=https://api.github.com/graphql
  2020-06-22T09:24:59.5838070Z PATH=/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/venv/bin:/Users/runner/.cargo/bin:/usr/local/lib/ruby/gems/2.6.0/bin:/usr/local/opt/ruby/bin:/usr/local/opt/curl/bin:/usr/local/bin:/usr/local/sbin:/Users/runner/bin:/Users/runner/.yarn/bin:/usr/local/go/bin:/Users/runner/Library/Android/sdk/tools:/Users/runner/Library/Android/sdk/platform-tools:/Users/runner/Library/Android/sdk/ndk-bundle:/Library/Frameworks/Mono.framework/Versions/Current/Commands:/usr/bin:/bin:/usr/sbin:/sbin:/Users/runner/.dotnet/tools:/Users/runner/.ghcup/bin:/Users/runner/hostedtoolcache/stack/2.3.1/x64:/Users/runner/Library/Python/3.7/bin
  2020-06-22T09:24:59.5838420Z PERFLOG_LOCATION_SETTING=RUNNER_PERFLOG
  2020-06-22T09:24:59.5839360Z PWD=/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer
  2020-06-22T09:24:59.5839590Z CONDA=/usr/local/miniconda
  2020-06-22T09:24:59.5839900Z EDGEWEBDRIVER=/usr/local/share/edge_driver
  2020-06-22T09:24:59.5840090Z DOTNET_ROOT=/Users/runner/.dotnet
  2020-06-22T09:24:59.5841390Z JAVA_HOME=/Library/Java/JavaVirtualMachines/zulu-8.jdk/Contents/Home
  2020-06-22T09:24:59.5842940Z JAVA_HOME_7_X64=/Library/Java/JavaVirtualMachines/zulu-7.jdk/Contents/Home
  2020-06-22T09:24:59.5843230Z VCPKG_INSTALLATION_ROOT=/usr/local/share/vcpkg
  2020-06-22T09:24:59.5844160Z JAVA_HOME_12_X64=/Library/Java/JavaVirtualMachines/zulu-12.jdk/Contents/Home
  2020-06-22T09:24:59.5844990Z LANG=en_US.UTF-8
  2020-06-22T09:24:59.5845190Z ImageOS=macos1015
  2020-06-22T09:24:59.5845340Z XPC_FLAGS=0x0
  2020-06-22T09:24:59.5845530Z PS1=(venv)
  2020-06-22T09:24:59.5845710Z XPC_SERVICE_NAME=0
  2020-06-22T09:24:59.5845900Z GECKOWEBDRIVER=/usr/local/opt/geckodriver/bin
  2020-06-22T09:24:59.5846100Z GITHUB_ACTOR=maltfield
  2020-06-22T09:24:59.5846290Z PACKAGES_PATH=/Users/runner/.buildozer/osx/packages
  2020-06-22T09:24:59.5846480Z HOME=/Users/runner
  2020-06-22T09:24:59.5846630Z SHLVL=5
  2020-06-22T09:24:59.5847570Z RUNNER_TRACKING_ID=github_80dd0850-2618-4146-a94e-2744c904f72c
  2020-06-22T09:24:59.5847830Z ANDROID_NDK_18R_PATH=/Users/runner/Library/Android/sdk/ndk/18.1.5063045
  2020-06-22T09:24:59.5848820Z GITHUB_WORKSPACE=/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui
  2020-06-22T09:24:59.5849070Z CI=true
  2020-06-22T09:24:59.5849260Z GITHUB_RUN_ID=143371247
  2020-06-22T09:24:59.5849450Z LOGNAME=runner
  2020-06-22T09:24:59.5850280Z LC_CTYPE=en_US.UTF-8
  2020-06-22T09:24:59.5851190Z JAVA_HOME_13_X64=/Library/Java/JavaVirtualMachines/zulu-13.jdk/Contents/Home
  2020-06-22T09:24:59.5852090Z HOMEBREW_CASK_OPTS=--no-quarantine
  2020-06-22T09:24:59.5853020Z POWERSHELL_DISTRIBUTION_CHANNEL=GitHub-Actions-macos1015
  2020-06-22T09:24:59.5853250Z BOOTSTRAP_HASKELL_NONINTERACTIVE=1
  2020-06-22T09:24:59.5854140Z ANDROID_NDK_HOME=/Users/runner/Library/Android/sdk/ndk-bundle
  2020-06-22T09:24:59.5854380Z XCODE_11_DEVELOPER_DIR=/Applications/Xcode_11.5.app/Contents/Developer
  2020-06-22T09:24:59.5855280Z GITHUB_REPOSITORY=maltfield/cross-platform-python-gui
  2020-06-22T09:24:59.5855500Z GITHUB_ACTION=run1
  2020-06-22T09:24:59.5855660Z _=/usr/bin/env
  2020-06-22T09:25:00.4306730Z [0m[1;30m# Install requirement python3 in virtualenv[0m
  2020-06-22T09:25:00.4308090Z [0m[1;30m# Run 'pip install --target=/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/applibs python3'[0m
  2020-06-22T09:25:00.4309080Z [0m[1;30m# Cwd /Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer[0m
  2020-06-22T09:25:00.4309230Z Collecting python3
  2020-06-22T09:25:00.5120970Z   ERROR: Could not find a version that satisfies the requirement python3 (from versions: none)
  2020-06-22T09:25:00.5146430Z ERROR: No matching distribution found for python3
  2020-06-22T09:25:00.6540200Z WARNING: You are using pip version 19.2.3, however version 20.1.1 is available.
  2020-06-22T09:25:00.6541800Z You should consider upgrading via the 'pip install --upgrade pip' command.
  2020-06-22T09:25:00.7058160Z [0m[1;31m# Command failed: pip install --target=/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/applibs python3[0m
  2020-06-22T09:25:00.7059440Z [0m[1;31m# ENVIRONMENT:[0m
  2020-06-22T09:25:00.7060430Z [0m[1;31m#     PACKAGES_PATH = '/Users/runner/.buildozer/osx/packages'[0m
  2020-06-22T09:25:00.7061330Z [0m[1;31m#     VIRTUAL_ENV = '/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/venv'[0m
  2020-06-22T09:25:00.7072180Z [0m[1;31m#     PATH = '/Users/runner/runners/2.263.0/work/cross-platform-python-gui/cross-platform-python-gui/buildozer/.buildozer/venv/bin:/Users/runner/.cargo/bin:/usr/local/lib/ruby/gems/2.6.0/bin:/usr/local/opt/ruby/bin:/usr/local/opt/curl/bin:/usr/local/bin:/usr/local/sbin:/Users/runner/bin:/Users/runner/.yarn/bin:/usr/local/go/bin:/Users/runner/Library/Android/sdk/tools:/Users/runner/Library/Android/sdk/platform-tools:/Users/runner/Library/Android/sdk/ndk-bundle:/Library/Frameworks/Mono.framework/Versions/Current/Commands:/usr/bin:/bin:/usr/sbin:/sbin:/Users/runner/.dotnet/tools:/Users/runner/.ghcup/bin:/Users/runner/hostedtoolcache/stack/2.3.1/x64:/Users/runner/Library/Python/3.7/bin'[0m
  2020-06-22T09:25:00.7073910Z [0m[1;31m#     CC = '/bin/false'[0m
  2020-06-22T09:25:00.7075080Z [0m[1;31m#     CXX = '/bin/false'[0m
  2020-06-22T09:25:00.7076070Z [0m[1;31m# [0m
  2020-06-22T09:25:00.7076940Z [0m[1;31m# Buildozer failed to execute the last command[0m
  2020-06-22T09:25:00.7077810Z [0m[1;31m# The error might be hidden in the log above this error[0m
  2020-06-22T09:25:00.7079550Z [0m[1;31m# Please read the full log, and search for it before[0m
  2020-06-22T09:25:00.7081000Z [0m[1;31m# raising an issue with buildozer itself.[0m
  2020-06-22T09:25:00.7086300Z [0m[1;31m# In case of a bug report, please add a full log with log_level = 2[0m

I'm removing 'python3' from the buildozer.spec requrements option and attempting to force package_app.py to skip the thinning step.

  # Please enter the commit message for your changes. Lines starting
  # with '#' will be ignored, and an empty message aborts the commit.
  #
  # On branch master
  # Your branch is up to date with 'origin/master'.
  #
  # Changes to be committed:
  #	modified:   buildDmg.sh
  #

Author: maltfield

build/mac/buildDmg.sh

@@ -10,8 +10,8 @@ set -x
 #          * https://github.com/kivy/buildozer/issues/494#issuecomment-390262889
 #
 # Authors: Michael Altfield <[email protected]>
-# Created: 2020-06-21
-# Updated: 2020-06-21
+# Created: 2020-06-22
+# Updated: 2020-06-22
 # Version: 0.1
 ################################################################################
 
@@ -176,7 +176,7 @@ package.domain = org.test
 source.dir = ../src/
 source.include_exts = py,png,jpg,kv,atlas
 version = 0.1
-requirements = python3,kivy
+requirements = kivy
 orientation = portrait
 osx.python_version = 3
 osx.kivy_version = 1.9.1
@@ -219,10 +219,14 @@ popd
 
 # Go into kivy sdk directory and fix the script package_app.py to use the specified python version.
 cp package_app.py package_app.py.orig
-echo "===package_app.py======================================================="
-cat package_app.py
-echo "===package_app.py======================================================="
+echo "===package_app.py.orig======================================================="
+cat package_app.py.orig
+echo "===package_app.py.orig======================================================="
 sed -i '' "s;3.5.0;$PYTHON_VERSION;g" package_app.py
+
+# prevent auto-thinning
+sed -i '' "s;if not strip:;if True:;g" package_app.py
+
 ## Make it python3 compatible by removing decode(...) calls.
 #sed -i '' "s;\.decode('utf-8');;g" package_app.py
 diff package_app.py.orig package_app.py