Clear VisualStudio internal cache and installed visual studios data structures when vswhere finds new msvc roots.

Author: jcbrill

CHANGES.txt

@@ -80,13 +80,14 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
       of the results from all vswhere executables).  There is a single invocation for
       each vswhere executable that processes the output for all installations.  Prior
       implementations called the vswhere executable for each supported msvc version.
-    - Previously, the installed vcs list was constructed once and cached at runtime.  If
-      a vswhere executable was specified via the construction variable VSWHERE and found
-      additional msvc installations, the new installations were not reflected in the
-      installed vcs list. During runtime, if a user-specified vswhere executable finds
-      new msvc installations, internal runtime caches are cleared and the installed vcs
-      list is reconstructed.
-  
+    - Previously, the installed vcs and visual studios lists were constructed once and
+      cached at runtime.  If a vswhere executable was specified via the construction
+      variable VSWHERE and found additional msvc installations, the new installations
+      were not reflected in the installed vcs and visual studios lists. Now, when a
+      user-specified vswhere executable finds new msvc installations, internal runtime
+      caches are cleared and the installed vcs and visual studios lists are reconstructed
+      on their next retrieval.
+
   From Thaddeus Crews:
     - Implemented SCons.Util.sctyping as a safe means of hinting complex types. Currently
       only implemented for `Executor` as a proof-of-concept.
@@ -1404,7 +1405,7 @@ RELEASE 3.1.2 - Mon, 17 Dec 2019 02:06:27 +0000
       in the case where a child process is spawned while a Python action has a
       file open. Original author: Ryan Beasley.
     - Added memoization support for calls to Environment.Value() in order to
-	  improve performance of repeated calls.
+      improve performance of repeated calls.
 
 
   From Jason Kenny

RELEASE.txt

@@ -70,11 +70,13 @@ FIXES
       msiexec /i VCForPython27.msi ALLUSERS=1
   When installed for all users, Visual Studio 2008 (9.0) Visual C++ For Python is
   now correctly detected.
-- MSVC: The installed vcs list was constructed and cached during the initial
-  invocation. If a vswhere executable was specified via the construction variable
-  VSWHERE and found additional msvc installations, the new installations were not
-  reflected in the installed vcs list. Now, when a user-specified vswhere
-  executable finds new msvc installations, the installed vcs list is reconstructed.
+- MSVC: The installed vcs and visual studios lists were constructed and cached
+  during their initial invocations. If a vswhere executable was specified via the
+  construction variable VSWHERE and found additional msvc installations, the new
+  installations were not reflected in the cached installed vcs and visual studios
+  lists. Now, when a user-specified vswhere executable finds new msvc installations,
+  the installed vcs and visual studios lists are cleared and reconstructed on their
+  next retrieval.
 - On Windows platform, when collecting command output (Configure checks),
   make sure decoding of bytes doesn't fail.
 - Documentation indicated that both Pseudo() and env.Pseudo() were usable,

SCons/Tool/MSCommon/vc.py

@@ -1008,7 +1008,8 @@ def msvc_find_vswhere():
 
 class _VSWhere:
 
-    reset_funcs = []
+    reset_funcs_list = []
+    reset_funcs_seen = set()
 
     @classmethod
     def reset(cls):
@@ -1036,15 +1037,20 @@ def msvc_instances_default_order(a, b):
 
     @classmethod
     def register_reset_func(cls, func):
-        cls.reset_funcs.append(func)
+        if func and func not in cls.reset_funcs_seen:
+            cls.reset_funcs_seen.add(func)
+            cls.reset_funcs_list.append(func)
 
     @classmethod
     def call_reset_funcs(cls):
-        for func in cls.reset_funcs:
+        for func in cls.reset_funcs_list:
             func()
 
 _VSWhere.reset()
 
+def vswhere_register_reset_func(func):
+    _VSWhere.register_reset_func(func)
+
 def _filter_vswhere_paths(env):
 
     vswhere_paths = []
@@ -1117,7 +1123,7 @@ def _vswhere_query_json_output(vswhere_exe, vswhere_args):
     'vc_component_suffix',
 ])
 
-def _update_vswhere_msvc_map(env):
+def _vswhere_update_msvc_map(env):
 
     vswhere_paths = _filter_vswhere_paths(env)
     if not vswhere_paths:
@@ -1241,6 +1247,9 @@ def _update_vswhere_msvc_map(env):
 
     return _VSWhere.msvc_map
 
+def vswhere_update_msvc(env):
+    _vswhere_update_msvc_map(env)
+
 _cache_pdir_vswhere_queries = {}
 
 def _reset_pdir_vswhere_queries():
@@ -1267,7 +1276,7 @@ def find_vc_pdir_vswhere(msvc_version, env=None):
     """
     global _cache_pdir_vswhere_queries
 
-    msvc_map = _update_vswhere_msvc_map(env)
+    msvc_map = _vswhere_update_msvc_map(env)
     if not msvc_map:
         return None
 
@@ -1751,9 +1760,9 @@ def _check_files_exist_in_vc_dir(env, vc_dir, msvc_version) -> bool:
 def get_installed_vcs(env=None):
     global __INSTALLED_VCS_RUN
 
-    # the installed vcs cache is cleared
-    # if new vc roots are discovered
-    _update_vswhere_msvc_map(env)
+    debug('')
+    # the installed vcs cache is cleared if new vc roots are discovered
+    _vswhere_update_msvc_map(env)
 
     if __INSTALLED_VCS_RUN is not None:
         return __INSTALLED_VCS_RUN

SCons/Tool/MSCommon/vs.py

@@ -28,7 +28,6 @@
 import os
 
 import SCons.Errors
-import SCons.Tool.MSCommon.vc
 import SCons.Util
 
 from .common import (
@@ -40,6 +39,14 @@
     read_reg,
 )
 
+from .vc import (
+    find_vc_pdir,
+    get_msvc_version_numeric,
+    reset_installed_vcs,
+    vswhere_register_reset_func,
+    vswhere_update_msvc,
+)
+
 
 class VisualStudio:
     """
@@ -48,6 +55,7 @@ class VisualStudio:
     """
     def __init__(self, version, **kw) -> None:
         self.version = version
+        self.vernum = float(get_msvc_version_numeric(version))
         kw['vc_version']  = kw.get('vc_version', version)
         kw['sdk_version'] = kw.get('sdk_version', version)
         self.__dict__.update(kw)
@@ -66,7 +74,7 @@ def find_batch_file(self):
         return batch_file
 
     def find_vs_dir_by_vc(self, env):
-        dir = SCons.Tool.MSCommon.vc.find_vc_pdir(self.vc_version, env)
+        dir = find_vc_pdir(self.vc_version, env)
         if not dir:
             debug('no installed VC %s', self.vc_version)
             return None
@@ -411,8 +419,12 @@ def reset(self) -> None:
     ),
 ]
 
+SupportedVSWhereList = []
 SupportedVSMap = {}
 for vs in SupportedVSList:
+    if vs.vernum >= 14.1:
+        # VS2017 and later detected via vswhere.exe
+        SupportedVSWhereList.append(vs)
     SupportedVSMap[vs.version] = vs
 
 
@@ -428,6 +440,12 @@ def reset(self) -> None:
 def get_installed_visual_studios(env=None):
     global InstalledVSList
     global InstalledVSMap
+    debug('')
+    # Calling vswhere_update_msvc may cause installed caches to be cleared.
+    # The installed vcs and visual studios are cleared when new vc roots
+    # are discovered which causes the InstalledVSList and InstalledVSMap
+    # variables to be set to None.
+    vswhere_update_msvc(env)
     if InstalledVSList is None:
         InstalledVSList = []
         InstalledVSMap = {}
@@ -442,14 +460,28 @@ def get_installed_visual_studios(env=None):
 def reset_installed_visual_studios() -> None:
     global InstalledVSList
     global InstalledVSMap
+    debug('')
     InstalledVSList = None
     InstalledVSMap  = None
     for vs in SupportedVSList:
         vs.reset()
 
     # Need to clear installed VC's as well as they are used in finding
     # installed VS's
-    SCons.Tool.MSCommon.vc.reset_installed_vcs()
+    reset_installed_vcs()
+
+def _reset_installed_vswhere_visual_studios():
+    # vswhere found new roots: reset VS2017 and later
+    global InstalledVSList
+    global InstalledVSMap
+    debug('')
+    InstalledVSList = None
+    InstalledVSMap  = None
+    for vs in SupportedVSWhereList:
+        vs.reset()
+
+# register vswhere callback function
+vswhere_register_reset_func(_reset_installed_vswhere_visual_studios)
 
 
 # We may be asked to update multiple construction environments with