Merge pull request #417 from madcowswe/feature/fix_windows_build

Fix hang on compile on Windows

Firmware/Tupfile.lua

@@ -1,6 +1,22 @@
 
 tup.include('build.lua')
 
+-- If we simply invoke python or python3 on a pristine Windows 10, it will try
+-- to open the Microsoft Store which will not work and hang tup instead. The
+-- command "python --version" does not open the Microsoft Store.
+-- On some systems this may return a python2 command if Python3 is not installed.
+function find_python3()
+    success, python_version = run_now("python3 --version")
+    if success then return "python3" end
+    io.stderr:write("This should go to stderr\n")
+    success, python_version = run_now("python --version")
+    if success then return "python" end
+    error("Python 3 not found.")
+end
+
+python_command = find_python3()
+print('Using python command "'..python_command..'"')
+
 -- Switch between board versions
 boardversion = tup.getconfig("BOARD_VERSION")
 if boardversion == "v3.1" then
@@ -146,7 +162,7 @@ build{
 }
 
 tup.frule{
-    command='python ../tools/odrive/version.py --output %o',
+    command=python_command..' ../tools/odrive/version.py --output %o',
     outputs={'build/version.h'}
 }
 

Firmware/build.lua

@@ -12,6 +12,14 @@ function string:split(sep)
     return fields
 end
 
+function run_now(command)
+    local handle
+    handle = io.popen(command)
+    local output = handle:read("*a")
+    local rc = {handle:close()}
+    return rc[1], output
+end
+
 -- Very basic parser to retrieve variables from a Makefile
 function parse_makefile_vars(makefile)
     vars = {}

docs/developer-guide.md

@@ -35,7 +35,7 @@ The recommended tools for ODrive development are:
  * **ARM GNU Compiler**: For cross-compiling code
  * **ARM GDB**: For debugging the code and stepping through on the device
  * **OpenOCD**: For flashing the ODrive with the STLink/v2 programmer
- * **Python**: For running the Python tools
+ * **Python**: For running the Python tools (`odrivetool`). Also required for compiling firmware.
 
 See below for specific installation instructions for your OS.
 
@@ -92,6 +92,7 @@ Some instructions in this document may assume that you're using a bash command p
   * __Note 2__: 8-2018-q4-major seems to have a bug on Windows.  Please use 7-2018-q2-update.
 * [Tup](http://gittup.org/tup/index.html)
 * [GNU MCU Eclipse's Windows Build Tools](https://github.com/gnu-mcu-eclipse/windows-build-tools/releases)
+* [Python 3](https://www.python.org/downloads/)
 * [OpenOCD](https://github.com/xpack-dev-tools/openocd-xpack/releases/). 
 * [ST-Link/V2 Drivers](http://www.st.com/web/en/catalog/tools/FM147/SC1887/PF260219)