MSVS/MSVC: msvs tool, msvs tests, and msvc detection fixes

Updates:
* Fix issue SCons#2755: the msvs tool no longer writes the OS environment SCONS_HOME value into the SCons environment when the SCONS_HOME variable already exists in the SCons environment.
* Update the windows registry keys for detection of Visual Studio 2015 Express ('14.0Exp'): the VS2015 registry key ('WDExpress') appears to be different than the registry key ('VCExpress') for earlier Visual Studio express versions.
* Fix the vs-6.0-exec.py test script: the msvs generated project is 'foo.dsp' and the command-line invocation of the Visual Studio development environment program was attempting to build 'test.dsp'.
* Update the msvs project generation test scripts: the msvs project execution tests could produce a "false positive" test result when the test executable is correctly built via the SConstruct env.Program() call and the command-line invocation of the Visual Studio development environment program fails.

Author: jcbrill

CHANGES.txt

@@ -8,6 +8,31 @@ NOTE: The 4.0.0 Release of SCons dropped Python 2.7 Support
 NOTE: 4.3.0 now requires Python 3.6.0 and above. Python 3.5.x is no longer supported
 
 RELEASE  VERSION/DATE TO BE FILLED IN LATER
+
+  From Joseph Brill:
+    - Fix issue #2755: the msvs tool no longer writes the OS environment SCONS_HOME
+      value into the SCons environment when the SCONS_HOME variable already exists
+      in the SCons environment.  Prior to this change, a valid user-defined SCons
+      environment value for SCONS_HOME would be overwritten with the OS environment
+      value of SCONS_HOME which could be None (i.e., undefined).
+    - Update the windows registry keys for detection of Visual Studio 2015 Express
+      ('14.0Exp'): the VS2015 registry key ('WDExpress') appears to be different
+      than the registry key ('VCExpress') for earlier Visual Studio express
+      versions.  The registry key value is relative to the installation root rather
+      than the VC folder and requires additional path components during evaluation.
+    - Fix the vs-6.0-exec.py test script: the msvs generated project is 'foo.dsp'
+      and the command-line invocation of the Visual Studio development environment
+      program was attempting to build 'test.dsp'.  The command-line invocation was
+      changed to build 'foo.dsp'.
+    - Update the msvs project generation test scripts: the msvs project execution
+      tests could produce a "false positive" test result when the test executable is
+      correctly built via the SConstruct env.Program() call and the command-line
+      invocation of the Visual Studio development environment program fails.  The
+      test passes due to the existence of the test executable from the initial
+      build.  The tests were modified to delete the test executable, object file,
+      and sconsign file prior to the command-line invocation of the VS development
+      binary.
+
   From Michał Górny:
     - Remove unecessary dependencies on pypi packages from setup.cfg
 

RELEASE.txt

@@ -34,6 +34,16 @@ FIXES
 
 - Fix of the --debug=sconscript option to return exist statements when using return
   statement with stop flag enabled
+- MSVS: prevent overwriting the SCons environment variable SCONS_HOME with the OS
+  environment value of SCONS_HOME in the msvs tool.
+- MSVC: Fix the detection of Visual Studio 2015 Express ('14.0Exp') by adding a
+  registry key definition and updating the installation root-relative registry value
+  at runtime for the location of the VC folder.
+- MSVS: Fix the msvs project generation test for MSVS 6.0 to use the correct name of
+  the generated project file.
+- MSVS: Fix the msvs project generation test scripts so that "false positive" tests
+  results are not possible when the initial build is successful and the command-line
+  build of the project file fails.
 
 IMPROVEMENTS
 ------------

SCons/Tool/MSCommon/vc.py

@@ -718,6 +718,7 @@ def _skip_sendtelemetry(env):
     '14.0': [
         (SCons.Util.HKEY_LOCAL_MACHINE, r'Microsoft\VisualStudio\14.0\Setup\VC\ProductDir')],
     '14.0Exp': [
+        (SCons.Util.HKEY_LOCAL_MACHINE, r'Microsoft\WDExpress\14.0\Setup\VS\ProductDir'),
         (SCons.Util.HKEY_LOCAL_MACHINE, r'Microsoft\VCExpress\14.0\Setup\VC\ProductDir')],
     '12.0': [
         (SCons.Util.HKEY_LOCAL_MACHINE, r'Microsoft\VisualStudio\12.0\Setup\VC\ProductDir'),
@@ -905,9 +906,14 @@ def find_vc_pdir(env, msvc_version):
         except OSError:
             debug('no VC registry key %s', repr(key))
         else:
-            if msvc_version == '9.0' and key.lower().endswith('\\vcforpython\\9.0\\installdir'):
-                # Visual C++ for Python registry key is installdir (root) not productdir (vc)
-                comps = os.path.join(comps, 'VC')
+            if msvc_version == '9.0':
+                if key.lower().endswith('\\vcforpython\\9.0\\installdir'):
+                    # Visual C++ for Python registry key is installdir (root) not productdir (vc)
+                    comps = os.path.join(comps, 'VC')
+            elif msvc_version == '14.0Exp':
+                if key.lower().endswith('\\setup\\vs\\productdir'):
+                    # Visual Studio 14.0 Express registry key is installdir (root) not productdir (vc)
+                    comps = os.path.join(comps, 'VC')
             debug('found VC in registry: %s', comps)
             if os.path.exists(comps):
                 return comps

SCons/Tool/msvs.py

@@ -145,6 +145,8 @@ def msvs_parse_version(s):
 # the MSVS Project file invoke SCons the same way that scons.bat does,
 # which works regardless of how we were invoked.
 def getExecScriptMain(env, xml=None):
+    if 'SCONS_HOME' not in env:
+        env['SCONS_HOME'] = os.environ.get('SCONS_HOME')
     scons_home = env.get('SCONS_HOME')
     if not scons_home and 'SCONS_LIB_DIR' in os.environ:
         scons_home = os.environ['SCONS_LIB_DIR']
@@ -2109,7 +2111,9 @@ def generate(env) -> None:
     env['GET_MSVSSOLUTIONSUFFIX']  = GetMSVSSolutionSuffix
     env['MSVSPROJECTSUFFIX']  = '${GET_MSVSPROJECTSUFFIX}'
     env['MSVSSOLUTIONSUFFIX']  = '${GET_MSVSSOLUTIONSUFFIX}'
-    env['SCONS_HOME'] = os.environ.get('SCONS_HOME')
+
+    if 'SCONS_HOME' not in env:
+        env['SCONS_HOME'] = os.environ.get('SCONS_HOME')
 
 def exists(env):
     return msvc_setup_env_tool(env, tool=tool_name)

test/MSVS/vs-10.0-exec.py

@@ -90,6 +90,11 @@
 
 test.run(chdir='sub dir', arguments='.')
 
+for filename in ('foo.exe', 'foo.obj', '.sconsign.dblite'):
+    filepath = test.workpath('sub dir', filename)
+    if os.path.exists(filepath):
+        test.unlink(filepath)
+
 test.vcproj_sys_path(test.workpath('sub dir', 'foo.vcxproj'))
 
 import SCons.Platform.win32

test/MSVS/vs-10.0Exp-exec.py

@@ -91,6 +91,11 @@
 
 test.run(chdir='sub dir', arguments='.')
 
+for filename in ('foo.exe', 'foo.obj', '.sconsign.dblite'):
+    filepath = test.workpath('sub dir', filename)
+    if os.path.exists(filepath):
+        test.unlink(filepath)
+
 test.vcproj_sys_path(test.workpath('sub dir', 'foo.vcxproj'))
 
 import SCons.Platform.win32

test/MSVS/vs-11.0-exec.py

@@ -91,6 +91,11 @@
 
 test.run(chdir='sub dir', arguments='.')
 
+for filename in ('foo.exe', 'foo.obj', '.sconsign.dblite'):
+    filepath = test.workpath('sub dir', filename)
+    if os.path.exists(filepath):
+        test.unlink(filepath)
+
 test.vcproj_sys_path(test.workpath('sub dir', 'foo.vcxproj'))
 
 import SCons.Platform.win32

test/MSVS/vs-11.0Exp-exec.py

@@ -91,6 +91,11 @@
 
 test.run(chdir='sub dir', arguments='.')
 
+for filename in ('foo.exe', 'foo.obj', '.sconsign.dblite'):
+    filepath = test.workpath('sub dir', filename)
+    if os.path.exists(filepath):
+        test.unlink(filepath)
+
 test.vcproj_sys_path(test.workpath('sub dir', 'foo.vcxproj'))
 
 import SCons.Platform.win32

test/MSVS/vs-14.0-exec.py

@@ -92,6 +92,11 @@
 
 test.run(chdir='sub dir', arguments='.')
 
+for filename in ('foo.exe', 'foo.obj', '.sconsign.dblite'):
+    filepath = test.workpath('sub dir', filename)
+    if os.path.exists(filepath):
+        test.unlink(filepath)
+
 test.vcproj_sys_path(test.workpath('sub dir', 'foo.vcxproj'))
 
 import SCons.Platform.win32

test/MSVS/vs-14.0Exp-exec.py

@@ -55,10 +55,14 @@
 
 test.run(arguments = '-n -q -Q -f -', stdin = """\
 env = Environment(tools = ['msvc'], MSVS_VERSION='%(msvs_version)s')
-sconsEnv = repr(env['ENV'])
-print("os.environ.update(" + sconsEnv + ")")
+if env.WhereIs('cl'):
+    print("os.environ.update(%%s)" %% repr(env['ENV']))
 """ % locals())
 
+if test.stdout() == "":
+    msg = "Visual Studio %s missing cl.exe; skipping test.\n" % msvs_version
+    test.skip_test(msg)
+
 exec(test.stdout())
 
 
@@ -88,6 +92,11 @@
 
 test.run(chdir='sub dir', arguments='.')
 
+for filename in ('foo.exe', 'foo.obj', '.sconsign.dblite'):
+    filepath = test.workpath('sub dir', filename)
+    if os.path.exists(filepath):
+        test.unlink(filepath)
+
 test.vcproj_sys_path(test.workpath('sub dir', 'foo.vcxproj'))
 
 import SCons.Platform.win32