[WIP] MSVC: detection fixes and changes

CHANGES.txt

@@ -47,6 +47,60 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
       msvs. Moving any of these tools that used relative imports to the scons site tools
       folder would fail on import (i.e., the relative import paths become invalid when
       moved).
+    - The detection of the msvc compiler executable (cl.exe) has been modified.  The
+      compiler detection no longer considers the host os environment path.  In addition,
+      existence of the msvc compiler executable is checked in the detection dictionary
+      and the scons ENV path before the detection dictionary is merged into the scons
+      ENV.  Different warnings are produced when the msvc compiler is not detected in the
+      detection dictionary based on whether or not an msvc compiler was detected in the
+      scons ENV path (i.e., already exists in the user's ENV path prior to detection).
+    - For msvc version specifications without an 'Exp' suffix, an express installation
+      is used when no other edition is detected for the msvc version.
+    - VS2015 Express (14.1Exp) may not have been detected. The registry keys written
+      during installation appear to be different than for earlier express versions.
+      VS2015 Express should be correctly detected now.
+    - VS2015 Express (14.1Exp) does not support the sdk version argument.  VS2015 Express
+      does not support the store argument for target architectures other than x86.
+      Script argument validation now takes into account these restrictions.
+    - VS2015 BuildTools (14.0) does not support the sdk version argument and does not
+      support the store argument.  Script argument validation now takes into account
+      these restrictions.
+    - The Windows SDK for Windows 7 and .NET Framework 4" (SDK 7.1) populates the
+      registry keys in a manner in which the msvc detection would report that VS2010
+      (10.0) is installed when only the SDK was installed.  The installed files are
+      intended to be used via the sdk batch file setenv.cmd. The installed msvc
+      batch files will fail. The msvc detection logic now ignores SDK-only VS2010
+      installations.  Similar protection is implemented for the sdk-only installs that
+      populate the installation folder and registry keys for VS2008 (9.0), if necessary.
+    - For VS2005 (8.0) to VS2015 (14.0), vsvarsall.bat is employed to dispatch to a
+      dependent batch file when configuring the msvc environment.  Previously, only the
+      existence of the compiler executable was verified. In certain installations, the
+      dependent batch file (e.g., vcvars64.bat) may not exist while the compiler
+      executable does exist resulting in build failures.  The existence of vcvarsall.bat,
+      the dependent batch file, and the compiler executable are now validated.
+    - MSVC configuration data specific to versions VS2005 (8.0) to VS2008 (9.0) was added
+      as the dependent batch files have different names than the batch file names used
+      for VS2010 (10.0) and later.  The VS2008 (9.0) Visual C++ For Python installation
+      is handled as a special case as the dependent batch files are: (a) not used and (b)
+      in different locations.
+    - When VS2008 (9.0) Visual C++ For Python is installed using the ALLUSERS=1 option
+      (i.e., msiexec /i VCForPython27.msi ALLUSERS=1), the registry keys are written to
+      HKEY_LOCAL_MACHINE rather than HKEY_CURRENT_USER.  An entry was added to query the
+      Visual C++ For Python keys in HKLM following the HKCU query.
+    - The registry detection of VS2015 (14.0), and earlier, is now cached at runtime and
+      is only evaluated once for each msvc version.
+    - The vswhere detection of VS2017 (14.1), and later, is now cached at runtime and is
+      only evaluated once for each vswhere executable.  The detected msvc instances for
+      all vswhere executables are merged (i.e., detected msvc instances are the union
+      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.
 
   From Vitaly Cheptsov:
     - Fix race condition in `Mkdir` which can happen when two `SConscript`

RELEASE.txt

@@ -59,6 +59,14 @@ CHANGED/ENHANCED EXISTING FUNCTIONALITY
   batch file exists but an individual msvc toolset may not support the host/target
   architecture combination.  For example, when using VS2022 on arm64, the arm64 native
   tools are only installed for the 14.3x toolsets.
+- MSVC: When the msvc compiler executable is not found during setup of the msvc
+  environment, the warning message issued takes into account whether or not a
+  possibly erroneous compiler executable was already present in the scons environment
+  path.
+- MSVC: For msvc version specifications without an 'Exp' suffix, an express
+  installation is used when no other edition is detected for the msvc version.
+  This was the behavior for VS2008 (9.0) through VS2015 (14.0).  This behavior
+  was extended to VS2017 (14.1) and VS2008 (8.0).
 - Extend range of recognized Java versions to 20.
 - Builder calls (like Program()) now accept pathlib objects in source lists.
 - The Help() function now takes an additional keyword argument keep_local:
@@ -102,6 +110,26 @@ FIXES
 - MSVC: Erroneous construction of the installed msvc list (as described above) caused an
   index error in the msvc support code.  An explicit check was added to prevent indexing
   into an empty list.  Fixes #4312.
+- MSVC: The search for the msvc compiler executable (cl.exe) no longer inspects the
+  OS system path in certain situations when setting up the msvc environment.
+- MSVC: VS2015 Express (14.1Exp) may not have been detected. VS2015 Express should
+  be correctly detected.
+- MSVC: VS2010 (10.0) could be inadvertently detected due to an sdk-only install
+  of Windows SDK 7.1.  An sdk-only install of VS2010 is ignored as the msvc batch
+  files will fail. The installed files are intended to be used in conjunction with
+  the SDK batch file.  Similar protection was added for VS2008 (9.0).
+- MSVC: For VS2005 (8.0) to VS2015 (14.0), detection of installed files was expanded
+  to include the primary msvc batch file, dependent msvc batch file, and compiler
+  executable. In certain installations, the dependent msvc batch file may not exist
+  while the compiler executable does exists resulting in a build failure.
+- MSVC: VS2008 (9.0) Visual C++ For Python was not detected when installed using the
+  ALLUSERS=1 option (i.e., msiexec /i VCForPython27.msi ALLUSERS=1).  When installed
+  for all users, VS2008 (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.
 - MSCommon: Test SConfTests.py would fail when mscommon debugging was enabled via the
   MSVC_MSCOMMON_DEBUG environment variable.  The mscommon logging filter class registered
   with the python logging module was refactored to prevent test failure.
@@ -126,6 +154,12 @@ IMPROVEMENTS
   msvs. Moving any of these tools that used relative imports to the scons site tools
   folder would fail on import (i.e., the relative import paths become invalid when
   moved).
+- MSVC: VS2015 Express (14.1Exp) does not support the sdk version argument. VS2015
+  Express does not support the store argument for target architectures other than
+  x86.  Script argument validation now takes into account these restrictions.
+- MSVC: VS2015 BuildTools (14.0) does not support the sdk version argument and
+  does not support the store argument.  Script argument validation now takes into
+  account these restrictions.
 
 PACKAGING
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