try_compile: Record propagated CMake variables in configure log

These provide more detailed information about how the test project was
configured.

Issue: #23200

Help/manual/cmake-configure-log.7.rst

@@ -190,6 +190,8 @@ A ``try_compile-v1`` event is a YAML mapping:
   directories:
     source: "/path/to/.../TryCompile-01234"
     binary: "/path/to/.../TryCompile-01234"
+  cmakeVariables:
+    SOME_VARIABLE: "Some Value"
   buildResult:
     variable: "COMPILE_RESULT"
     cached: true
@@ -217,6 +219,12 @@ The keys specific to ``try_compile-v1`` mappings are:
     For non-project invocations, this is often the same as
     the source directory.
 
+``cmakeVariables``
+  An optional key that is present when CMake propagates variables
+  into the test project, either automatically or due to the
+  :variable:`CMAKE_TRY_COMPILE_PLATFORM_VARIABLES` variable.
+  Its value is a mapping from variable names to their values.
+
 ``buildResult``
   A mapping describing the result of compiling the test code.
   It has the following keys:

Source/cmConfigureLog.cxx

@@ -193,6 +193,30 @@ void cmConfigureLog::WriteValue(cm::string_view key,
   this->EndObject();
 }
 
+void cmConfigureLog::WriteValue(cm::string_view key,
+                                std::map<std::string, std::string> const& map)
+{
+  static const std::string rawKeyChars = //
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"         //
+    "abcdefghijklmnopqrstuvwxyz"         //
+    "0123456789"                         //
+    "-_"                                 //
+    ;
+  this->BeginObject(key);
+  for (auto const& entry : map) {
+    if (entry.first.find_first_not_of(rawKeyChars) == std::string::npos) {
+      this->WriteValue(entry.first, entry.second);
+    } else {
+      this->BeginLine();
+      this->Encoder->write(entry.first, &this->Stream);
+      this->Stream << ": ";
+      this->Encoder->write(entry.second, &this->Stream);
+      this->EndLine();
+    }
+  }
+  this->EndObject();
+}
+
 void cmConfigureLog::WriteLiteralTextBlock(cm::string_view key,
                                            cm::string_view text)
 {

Source/cmConfigureLog.h

@@ -2,6 +2,7 @@
    file Copyright.txt or https://cmake.org/licensing for details.  */
 #pragma once
 
+#include <map>
 #include <memory>
 #include <string>
 #include <vector>
@@ -42,6 +43,8 @@ public:
   void WriteValue(cm::string_view key, int value);
   void WriteValue(cm::string_view key, std::string const& value);
   void WriteValue(cm::string_view key, std::vector<std::string> const& list);
+  void WriteValue(cm::string_view key,
+                  std::map<std::string, std::string> const& map);
 
   void WriteTextBlock(cm::string_view key, cm::string_view text);
   void WriteLiteralTextBlock(cm::string_view key, cm::string_view text);

Source/cmCoreTryCompile.cxx

@@ -471,6 +471,8 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
     return cm::nullopt;
   }
 
+  std::map<std::string, std::string> cmakeVariables;
+
   std::string outFileName = this->BinaryDirectory + "/CMakeLists.txt";
   // which signature are we using? If we are using var srcfile bindir
   if (this->SrcFileSignature) {
@@ -592,6 +594,7 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
             cmVersion::GetPatchVersion(), cmVersion::GetTweakVersion());
     if (def) {
       fprintf(fout, "set(CMAKE_MODULE_PATH \"%s\")\n", def->c_str());
+      cmakeVariables.emplace("CMAKE_MODULE_PATH", *def);
     }
 
     /* Set MSVC runtime library policy to match our selection.  */
@@ -653,10 +656,12 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
             this->Makefile->GetDefinition(rulesOverrideLang)) {
         fprintf(fout, "set(%s \"%s\")\n", rulesOverrideLang.c_str(),
                 rulesOverridePath->c_str());
+        cmakeVariables.emplace(rulesOverrideLang, *rulesOverridePath);
       } else if (cmValue rulesOverridePath2 =
                    this->Makefile->GetDefinition(rulesOverrideBase)) {
         fprintf(fout, "set(%s \"%s\")\n", rulesOverrideBase.c_str(),
                 rulesOverridePath2->c_str());
+        cmakeVariables.emplace(rulesOverrideBase, *rulesOverridePath2);
       }
     }
     fprintf(fout, "project(CMAKE_TRY_COMPILE%s)\n", projectLangs.c_str());
@@ -687,6 +692,9 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
               "set(CMAKE_%s_FLAGS \"${CMAKE_%s_FLAGS}"
               " ${COMPILE_DEFINITIONS}\")\n",
               li.c_str(), li.c_str());
+      if (flags) {
+        cmakeVariables.emplace(langFlags, *flags);
+      }
     }
     switch (this->Makefile->GetPolicyStatus(cmPolicies::CMP0066)) {
       case cmPolicies::WARN:
@@ -723,6 +731,9 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
           cmValue flagsCfg = this->Makefile->GetDefinition(langFlagsCfg);
           fprintf(fout, "set(%s %s)\n", langFlagsCfg.c_str(),
                   cmOutputConverter::EscapeForCMake(*flagsCfg).c_str());
+          if (flagsCfg) {
+            cmakeVariables.emplace(langFlagsCfg, *flagsCfg);
+          }
         }
       } break;
     }
@@ -757,6 +768,9 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
             this->Makefile->GetDefinition("CMAKE_EXE_LINKER_FLAGS");
           fprintf(fout, "set(CMAKE_EXE_LINKER_FLAGS %s)\n",
                   cmOutputConverter::EscapeForCMake(*exeLinkFlags).c_str());
+          if (exeLinkFlags) {
+            cmakeVariables.emplace("CMAKE_EXE_LINKER_FLAGS", *exeLinkFlags);
+          }
         }
         break;
     }
@@ -1044,12 +1058,14 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
       vars.erase(kCMAKE_OSX_ARCHITECTURES);
       std::string flag = "-DCMAKE_OSX_ARCHITECTURES=" + *tcArchs;
       arguments.CMakeFlags.emplace_back(std::move(flag));
+      cmakeVariables.emplace("CMAKE_OSX_ARCHITECTURES", *tcArchs);
     }
 
     for (std::string const& var : vars) {
       if (cmValue val = this->Makefile->GetDefinition(var)) {
         std::string flag = "-D" + var + "=" + *val;
         arguments.CMakeFlags.emplace_back(std::move(flag));
+        cmakeVariables.emplace(var, *val);
       }
     }
   }
@@ -1060,6 +1076,7 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
       if (cmValue val = this->Makefile->GetDefinition(var)) {
         std::string flag = "-D" + var + "=" + "'" + *val + "'";
         arguments.CMakeFlags.emplace_back(std::move(flag));
+        cmakeVariables.emplace(var, *val);
       }
     }
   }
@@ -1145,6 +1162,7 @@ cm::optional<cmTryCompileResult> cmCoreTryCompile::TryCompileCode(
   if (arguments.LogDescription) {
     result.LogDescription = *arguments.LogDescription;
   }
+  result.CMakeVariables = std::move(cmakeVariables);
   result.SourceDirectory = sourceDirectory;
   result.BinaryDirectory = this->BinaryDirectory;
   result.Variable = *arguments.CompileResultVariable;
@@ -1304,6 +1322,9 @@ void cmCoreTryCompile::WriteTryCompileEventFields(
   log.WriteValue("source"_s, compileResult.SourceDirectory);
   log.WriteValue("binary"_s, compileResult.BinaryDirectory);
   log.EndObject();
+  if (!compileResult.CMakeVariables.empty()) {
+    log.WriteValue("cmakeVariables"_s, compileResult.CMakeVariables);
+  }
   log.BeginObject("buildResult"_s);
   log.WriteValue("variable"_s, compileResult.Variable);
   log.WriteValue("cached"_s, compileResult.VariableCached);

Source/cmCoreTryCompile.h

@@ -22,6 +22,7 @@ class cmRange;
 struct cmTryCompileResult
 {
   cm::optional<std::string> LogDescription;
+  std::map<std::string, std::string> CMakeVariables;
 
   std::string SourceDirectory;
   std::string BinaryDirectory;

Tests/RunCMake/try_compile/ConfigureLog-config.txt

@@ -20,6 +20,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_compile/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_compile/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "CMAKE_C_ABI_COMPILED"
       cached: true
@@ -41,6 +44,13 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_compile/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_compile/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:
+      ABCDEFGHIJKLMNOPQRSTUVWXYZ: "Upper case"(
+      CMAKE_[^
+]*)+
+      "WITH SPACE": "Space"
+      _-0123456789: "Other chars"
+      abcdefghijklmnopqrstuvwxyz: "Lower case"
     buildResult:
       variable: "COMPILE_RESULT"
       cached: true
@@ -58,6 +68,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_compile/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_compile/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "COMPILE_RESULT"
       cached: true

Tests/RunCMake/try_compile/ConfigureLog.cmake

@@ -1,10 +1,23 @@
 enable_language(C)
 
+set(CMAKE_TRY_COMPILE_PLATFORM_VARIABLES
+  ABCDEFGHIJKLMNOPQRSTUVWXYZ
+  abcdefghijklmnopqrstuvwxyz
+  _-0123456789
+  "WITH SPACE"
+  )
+set(ABCDEFGHIJKLMNOPQRSTUVWXYZ "Upper case")
+set(abcdefghijklmnopqrstuvwxyz "Lower case")
+set(_-0123456789 "Other chars")
+set("WITH SPACE" "Space")
+
 try_compile(COMPILE_RESULT
   SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/ConfigureLog-bad.c
   LOG_DESCRIPTION "Source that should not compile."
   )
 
+unset(CMAKE_TRY_COMPILE_PLATFORM_VARIABLES)
+
 try_compile(COMPILE_RESULT
   SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/ConfigureLog-test.c
   NO_LOG

Tests/RunCMake/try_compile/Inspect-config.txt

@@ -20,6 +20,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_compile/Inspect-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_compile/Inspect-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "CMAKE_C_ABI_COMPILED"
       cached: true
@@ -44,6 +47,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_compile/Inspect-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_compile/Inspect-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "CMAKE_CXX_ABI_COMPILED"
       cached: true

Tests/RunCMake/try_run/ConfigureLog-config.txt

@@ -19,6 +19,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "CMAKE_C_ABI_COMPILED"
       cached: true
@@ -40,6 +43,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "COMPILE_RESULT"
       cached: true
@@ -59,6 +65,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "COMPILE_RESULT"
       cached: true
@@ -83,6 +92,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "COMPILE_RESULT"
       cached: true
@@ -103,6 +115,9 @@ events:(
     directories:
       source: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
       binary: "[^"]*/Tests/RunCMake/try_run/ConfigureLog-build/CMakeFiles/CMakeScratch/TryCompile-[^/"]+"
+    cmakeVariables:(
+      CMAKE_[^
+]*)+
     buildResult:
       variable: "COMPILE_RESULT"
       cached: true