Fix VC++ redistributable detection to avoid needless re-download (#4596) (#4598)

The previous detection passed a ProductCode to IsMsiProductInstalled,
which expects an UpgradeCode. ProductCodes change with every
redistributable build, so the check failed on all machines that didn't
happen to have that exact build installed, causing the 18.5 MB
vc_redist.x64.exe to be downloaded and re-run on every install.

Switch primary detection to the registry method documented by Microsoft
(HKLM\\SOFTWARE\\Microsoft\\VisualStudio\\14.0\\VC\\Runtimes\\<arch>),
which is stable across installer builds and works for both x64 and
arm64. Keep the verified x64 UpgradeCode as a fallback.

Author: mamoreau-devolutions

InstallerExtras/CodeDependencies.iss

@@ -225,16 +225,58 @@ begin
   Result := ShellExec('', ExpandConstant('{tmp}{\}') + 'netcorecheck' + Dependency_ArchSuffix + '.exe', Version, '', SW_HIDE, ewWaitUntilTerminated, ResultCode) and (ResultCode = 0);
 end;
 
+function Dependency_IsVCRuntimeInstalled(const Arch: String; const Major, Minor, Bld: Cardinal): Boolean;
+var
+  InstalledFlag, InstMajor, InstMinor, InstBld: Cardinal;
+  Key: String;
+begin
+  // Canonical VC++ runtime detection per Microsoft docs:
+  // https://learn.microsoft.com/en-us/cpp/windows/redistributing-visual-cpp-files
+  // The redistributable installer writes these values to both registry views,
+  // so a plain HKLM read is correct from Inno Setup's 32-bit process.
+  Key := 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\' + Arch;
+  Result :=
+    RegQueryDWordValue(HKLM, Key, 'Installed', InstalledFlag) and (InstalledFlag = 1) and
+    RegQueryDWordValue(HKLM, Key, 'Major', InstMajor) and
+    RegQueryDWordValue(HKLM, Key, 'Minor', InstMinor) and
+    RegQueryDWordValue(HKLM, Key, 'Bld',   InstBld) and
+    ((InstMajor > Major) or
+     ((InstMajor = Major) and (InstMinor > Minor)) or
+     ((InstMajor = Major) and (InstMinor = Minor) and (InstBld >= Bld)));
+end;
+
 procedure Dependency_AddVC2015To2022;
+var
+  Arch, Url: String;
+  MinMajor, MinMinor, MinBld: Cardinal;
 begin
   // https://docs.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist
-  if not IsMsiProductInstalled(Dependency_String('{91EE571B-0E8A-4C65-9EAF-2E2F5FC60C00}', '{91EE571B-0E8A-4C65-9EAF-2E2F5FC60C00}'), PackVersionComponents(14, 30, 30704, 0)) then begin
-    Dependency_Add('vcredist2022' + Dependency_ArchSuffix + '.exe',
-      '/passive /norestart',
-      'Visual C++ 2015-2022 Redistributable (x64)' + Dependency_ArchTitle,
-      Dependency_String('https://aka.ms/vc14/vc_redist.x64.exe', 'https://aka.ms/vc14/vc_redist.x64.exe'),
-      '', False, False);
+  MinMajor := 14;
+  MinMinor := 30;
+  MinBld   := 30704;
+
+  if IsARM64 then begin
+    Arch := 'arm64';
+    Url  := 'https://aka.ms/vc14/vc_redist.arm64.exe';
+  end else begin
+    Arch := 'x64';
+    Url  := 'https://aka.ms/vc14/vc_redist.x64.exe';
   end;
+
+  // Primary: registry-based detection (Microsoft's documented method, stable
+  // across installer builds). Fallback: MSI UpgradeCode lookup for x64 only
+  // (the x64 UpgradeCode {36F68A90-...} is verified; keeping a fallback helps
+  // on unusual install states). See issue #4596 for the regression this
+  // replaces, where a ProductCode was mistakenly used with IsMsiProductInstalled.
+  if Dependency_IsVCRuntimeInstalled(Arch, MinMajor, MinMinor, MinBld) then Exit;
+  if (Arch = 'x64') and IsMsiProductInstalled('{36F68A90-239C-34DF-B58C-64B30153CE35}',
+       PackVersionComponents(MinMajor, MinMinor, MinBld, 0)) then Exit;
+
+  Dependency_Add('vcredist2022_' + Arch + '.exe',
+    '/passive /norestart',
+    'Visual C++ 2015-2022 Redistributable (' + Arch + ')',
+    Url,
+    '', False, False);
 end;