From 0122e0229309ea9e726f399cbea1038a386e5f63 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Wed, 1 May 2024 17:31:35 -0400
Subject: [PATCH] Ninja: Add COMMENT to custom command and target descriptions

Fixes: #15461
---
 Source/cmNinjaUtilityTargetGenerator.cxx          | 13 +++++++++++++
 .../Ninja/CustomCommandTargetComments.cmake       | 12 ++++++++++++
 Tests/RunCMake/Ninja/RunCMakeTest.cmake           | 15 +++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 Tests/RunCMake/Ninja/CustomCommandTargetComments.cmake

diff --git a/Source/cmNinjaUtilityTargetGenerator.cxx b/Source/cmNinjaUtilityTargetGenerator.cxx
index 11ebfb237f..54e6c0c169 100644
--- a/Source/cmNinjaUtilityTargetGenerator.cxx
+++ b/Source/cmNinjaUtilityTargetGenerator.cxx
@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <array>
 #include <iterator>
+#include <memory>
 #include <set>
 #include <string>
 #include <utility>
@@ -13,6 +14,7 @@
 #include "cmCustomCommand.h"
 #include "cmCustomCommandGenerator.h"
 #include "cmGeneratedFileStream.h"
+#include "cmGeneratorExpression.h"
 #include "cmGeneratorTarget.h"
 #include "cmGlobalNinjaGenerator.h"
 #include "cmLocalNinjaGenerator.h"
@@ -76,6 +78,8 @@ void cmNinjaUtilityTargetGenerator::WriteUtilBuildStatements(
   cmGlobalNinjaGenerator::CCOutputs util_outputs(gg);
   util_outputs.ExplicitOuts.emplace_back(utilCommandName);
 
+  std::string commandDesc;
+  cmGeneratorExpression ge(*this->GetLocalGenerator()->GetCMakeInstance());
   bool uses_terminal = false;
   {
     std::array<std::vector<cmCustomCommand> const*, 2> const cmdLists = {
@@ -87,6 +91,13 @@ void cmNinjaUtilityTargetGenerator::WriteUtilBuildStatements(
         cmCustomCommandGenerator ccg(ci, fileConfig, lg);
         lg->AppendCustomCommandDeps(ccg, deps, fileConfig);
         lg->AppendCustomCommandLines(ccg, commands);
+        if (ci.GetComment()) {
+          if (!commandDesc.empty()) {
+            commandDesc += "; ";
+          }
+          auto cge = ge.Parse(ci.GetComment());
+          commandDesc += cge->Evaluate(this->GetLocalGenerator(), config);
+        }
         util_outputs.Add(ccg.GetByproducts());
         if (ci.GetUsesTerminal()) {
           uses_terminal = true;
@@ -144,6 +155,8 @@ void cmNinjaUtilityTargetGenerator::WriteUtilBuildStatements(
     cmValue echoStr = genTarget->GetProperty("EchoString");
     if (echoStr) {
       desc = *echoStr;
+    } else if (!commandDesc.empty()) {
+      desc = commandDesc;
     } else {
       desc = "Running utility command for " + this->GetTargetName();
     }
diff --git a/Tests/RunCMake/Ninja/CustomCommandTargetComments.cmake b/Tests/RunCMake/Ninja/CustomCommandTargetComments.cmake
new file mode 100644
index 0000000000..cfadcb3096
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CustomCommandTargetComments.cmake
@@ -0,0 +1,12 @@
+enable_language(C)
+
+add_executable(hello hello.c)
+add_custom_command(TARGET hello PRE_BUILD
+  COMMENT "pre-build: $<1:genex>"
+  COMMAND "${CMAKE_COMMAND}" -E echo "$<TARGET_FILE:hello>")
+add_custom_command(TARGET hello PRE_LINK
+  COMMENT "pre-link: $<1:genex>"
+  COMMAND "${CMAKE_COMMAND}" -E echo "$<TARGET_FILE:hello>")
+add_custom_command(TARGET hello POST_BUILD
+  COMMENT "post-build: $<1:genex>"
+  COMMAND "${CMAKE_COMMAND}" -E echo "$<TARGET_FILE:hello>")
diff --git a/Tests/RunCMake/Ninja/RunCMakeTest.cmake b/Tests/RunCMake/Ninja/RunCMakeTest.cmake
index a0e59ee66d..cbf7f264df 100644
--- a/Tests/RunCMake/Ninja/RunCMakeTest.cmake
+++ b/Tests/RunCMake/Ninja/RunCMakeTest.cmake
@@ -389,6 +389,21 @@ function (run_ChangeBuildType)
 endfunction()
 run_ChangeBuildType()
 
+function (run_CustomCommandTargetComments)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/CustomCommandTargetComments-build)
+  run_cmake(CustomCommandTargetComments)
+  unset(RunCMake_TEST_OPTIONS)
+  run_ninja("${RunCMake_TEST_BINARY_DIR}" ${maybe_w_dupbuild_err})
+  if (NOT ninja_stdout MATCHES [[pre-build: genex; pre-link: genex; Linking C executable hello(\.exe)?; post-build: genex]])
+    string(REPLACE "\n" "\n  " ninja_stdout "${ninja_stdout}")
+    message(SEND_ERROR
+      "Custom command comments are not part of the description:\n"
+      "  ${ninja_stdout}"
+    )
+  endif ()
+endfunction()
+run_CustomCommandTargetComments()
+
 function(run_QtAutoMocSkipPch)
   set(QtX Qt${CMake_TEST_Qt_version})
   if(CMake_TEST_${QtX}Core_Version VERSION_GREATER_EQUAL 5.15.0)