cmake: Add --ignore-eol option to `-E compare_files` command

Fixes: #13007

Help/manual/cmake.1.rst

@@ -373,9 +373,10 @@ Available commands are:
 ``chdir <dir> <cmd> [<arg>...]``
   Change the current working directory and run a command.
 
-``compare_files <file1> <file2>``
+``compare_files [--ignore-eol] <file1> <file2>``
   Check if ``<file1>`` is same as ``<file2>``. If files are the same,
-  then returns 0, if not it returns 1.
+  then returns 0, if not it returns 1.  The ``--ignore-eol`` option
+  implies line-wise comparison and ignores LF/CRLF differences.
 
 ``copy <file>... <destination>``
   Copy files to ``<destination>`` (either file or directory).

Help/release/dev/compare_files-ignore-eol.rst

+compare_files-ignore-eol
+------------------------
+
+* The :manual:`cmake(1)` ``-E compare_files`` command learned a new
+  ``--ignore-eol`` option to specify that end-of-line differences (e.g. LF vs
+  CRLF) should be ignored when comparing files.

Source/cmcmd.cxx

@@ -78,7 +78,8 @@ void CMakeCommandUsage(const char* program)
     << "  capabilities              - Report capabilities built into cmake "
        "in JSON format\n"
     << "  chdir dir cmd [args...]   - run command in a given directory\n"
-    << "  compare_files file1 file2 - check if file1 is same as file2\n"
+    << "  compare_files [--ignore-eol] file1 file2\n"
+    << "                              - check if file1 is same as file2\n"
     << "  copy <file>... destination  - copy files to destination "
        "(either file or directory)\n"
     << "  copy_directory <dir>... destination   - copy content of <dir>... "
@@ -540,10 +541,20 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string>& args)
     }
 
     // Compare files
-    if (args[1] == "compare_files" && args.size() == 4) {
-      if (cmSystemTools::FilesDiffer(args[2], args[3])) {
-        std::cerr << "Files \"" << args[2] << "\" to \"" << args[3]
-                  << "\" are different.\n";
+    if (args[1] == "compare_files" && (args.size() == 4 || args.size() == 5)) {
+      bool filesDiffer;
+      if (args.size() == 4) {
+        filesDiffer = cmSystemTools::FilesDiffer(args[2], args[3]);
+      } else if (args[2] == "--ignore-eol") {
+        filesDiffer = cmsys::SystemTools::TextFilesDiffer(args[3], args[4]);
+      } else {
+        ::CMakeCommandUsage(args[0].c_str());
+        return 1;
+      }
+
+      if (filesDiffer) {
+        std::cerr << "Files \"" << args[args.size() - 2] << "\" to \""
+                  << args[args.size() - 1] << "\" are different.\n";
         return 1;
       }
       return 0;

Tests/RunCMake/CommandLine/E_compare_files-different-eol-result.txt

+1

Tests/RunCMake/CommandLine/E_compare_files-different-eol-stderr.txt

+^Files ".*/compare_files/lf" to ".*/compare_files/crlf" are different.$

Tests/RunCMake/CommandLine/E_compare_files-ignore-eol-nonexistent-result.txt

+1

Tests/RunCMake/CommandLine/E_compare_files-ignore-eol-nonexistent-stderr.txt

+^Files "nonexistent_a" to "nonexistent_b" are different.$

Tests/RunCMake/CommandLine/RunCMakeTest.cmake

@@ -18,6 +18,10 @@ run_cmake_command(Uno-src ${CMAKE_COMMAND} -B DummyBuildDir -UVAR)
 run_cmake_command(E-no-arg ${CMAKE_COMMAND} -E)
 run_cmake_command(E_capabilities ${CMAKE_COMMAND} -E capabilities)
 run_cmake_command(E_capabilities-arg ${CMAKE_COMMAND} -E capabilities --extra-arg)
+run_cmake_command(E_compare_files-different-eol ${CMAKE_COMMAND} -E compare_files ${RunCMake_SOURCE_DIR}/compare_files/lf ${RunCMake_SOURCE_DIR}/compare_files/crlf)
+run_cmake_command(E_compare_files-ignore-eol-same ${CMAKE_COMMAND} -E compare_files --ignore-eol ${RunCMake_SOURCE_DIR}/compare_files/lf ${RunCMake_SOURCE_DIR}/compare_files/crlf)
+run_cmake_command(E_compare_files-ignore-eol-empty ${CMAKE_COMMAND} -E compare_files --ignore-eol ${RunCMake_SOURCE_DIR}/compare_files/empty1 ${RunCMake_SOURCE_DIR}/compare_files/empty2)
+run_cmake_command(E_compare_files-ignore-eol-nonexistent ${CMAKE_COMMAND} -E compare_files --ignore-eol nonexistent_a nonexistent_b)
 run_cmake_command(E_echo_append ${CMAKE_COMMAND} -E echo_append)
 run_cmake_command(E_rename-no-arg ${CMAKE_COMMAND} -E rename)
 run_cmake_command(E_server-arg ${CMAKE_COMMAND} -E server --extra-arg)

Tests/RunCMake/CommandLine/compare_files/.gitattributes

+crlf eol=crlf
+lf eol=lf

Tests/RunCMake/CommandLine/compare_files/crlf

+line1

Tests/RunCMake/CommandLine/compare_files/lf

+line1