CMakePresets.json: Rework how --preset argument is handled

If a path argument with no -S or -B leads to a cache directory,
use that directory as the binary directory. Otherwise, use the
binary directory from the preset.

Fixes: #21311

Source/QtDialog/CMakeSetup.cxx

@@ -32,8 +32,7 @@ static const char* cmDocumentationUsage[][2] = {
     "  cmake-gui [options]\n"
     "  cmake-gui [options] <path-to-source>\n"
     "  cmake-gui [options] <path-to-existing-build>\n"
-    "  cmake-gui [options] -S <path-to-source> -B <path-to-build>\n"
-    "  cmake-gui [options] -S <path-to-source> --preset=<preset-name>\n" },
+    "  cmake-gui [options] -S <path-to-source> -B <path-to-build>\n" },
   { nullptr, nullptr }
 };
 

Source/cmCacheManager.cxx

@@ -162,6 +162,7 @@ bool cmCacheManager::LoadCache(const std::string& path, bool internal,
       cmSystemTools::Error(message.str());
     }
   }
+  this->CacheLoaded = true;
   return true;
 }
 

Source/cmCacheManager.h

@@ -66,6 +66,9 @@ public:
   //! Print the cache to a stream
   void PrintCache(std::ostream&) const;
 
+  //! Get whether or not cache is loaded
+  bool IsCacheLoaded() const { return this->CacheLoaded; }
+
   //! Get a value from the cache given a key
   cmProp GetInitializedCacheValue(const std::string& key) const;
 
@@ -204,6 +207,7 @@ private:
                             const CacheEntry& e, cmMessenger* messenger) const;
 
   std::map<std::string, CacheEntry> Cache;
+  bool CacheLoaded = false;
 
   // Cache version info
   unsigned int CacheMajorVersion = 0;

Source/cmState.cxx

@@ -135,6 +135,11 @@ bool cmState::DeleteCache(const std::string& path)
   return this->CacheManager->DeleteCache(path);
 }
 
+bool cmState::IsCacheLoaded() const
+{
+  return this->CacheManager->IsCacheLoaded();
+}
+
 std::vector<std::string> cmState::GetCacheEntryKeys() const
 {
   return this->CacheManager->GetCacheEntryKeys();

Source/cmState.h

@@ -87,6 +87,8 @@ public:
 
   bool DeleteCache(const std::string& path);
 
+  bool IsCacheLoaded() const;
+
   std::vector<std::string> GetCacheEntryKeys() const;
   cmProp GetCacheEntryValue(std::string const& key) const;
   std::string GetSafeCacheEntryValue(std::string const& key) const;

Source/cmake.cxx

@@ -727,6 +727,7 @@ void cmake::SetArgs(const std::vector<std::string>& args)
 {
   bool haveToolset = false;
   bool havePlatform = false;
+  bool haveBArg = false;
 #if !defined(CMAKE_BOOTSTRAP)
   std::string profilingFormat;
   std::string profilingOutput;
@@ -775,6 +776,7 @@ void cmake::SetArgs(const std::vector<std::string>& args)
       path = cmSystemTools::CollapseFullPath(path);
       cmSystemTools::ConvertToUnixSlashes(path);
       this->SetHomeOutputDirectory(path);
+      haveBArg = true;
     } else if ((i < args.size() - 2) &&
                cmHasLiteralPrefix(arg, "--check-build-system")) {
       this->CheckBuildSystemArgument = args[++i];
@@ -1057,7 +1059,7 @@ void cmake::SetArgs(const std::vector<std::string>& args)
       return;
     }
 
-    if (!haveBinaryDir) {
+    if (!this->State->IsCacheLoaded() && !haveBArg) {
       this->SetHomeOutputDirectory(expandedPreset->BinaryDir);
     }
     if (!this->GlobalGenerator) {

Source/cmakemain.cxx

@@ -49,8 +49,7 @@ const char* cmDocumentationUsage[][2] = {
   { nullptr,
     "  cmake [options] <path-to-source>\n"
     "  cmake [options] <path-to-existing-build>\n"
-    "  cmake [options] -S <path-to-source> -B <path-to-build>\n"
-    "  cmake [options] -S <path-to-source> --preset=<preset-name>" },
+    "  cmake [options] -S <path-to-source> -B <path-to-build>" },
   { nullptr,
     "Specify a source directory to (re-)generate a build system for "
     "it in the current working directory.  Specify an existing build "