[CommandLine] Do not print empty categories with '--help-hidden'

llvm/docs/CommandLine.rst

@@ -1521,8 +1521,7 @@ passed to the constructor as ``const char*``.
 Note that declaring an option category and associating it with an option before
 parsing options (e.g. statically) will change the output of ``-help`` from
 uncategorized to categorized. If an option category is declared but not
-associated with an option then it will be hidden from the output of ``-help``
-but will be shown in the output of ``-help-hidden``.
+associated with an option then it will be hidden from the output of ``-help``.
 
 .. _different parser:
 .. _discussed previously:

llvm/lib/Support/CommandLine.cpp

@@ -2474,8 +2474,7 @@ class CategorizedHelpPrinter : public HelpPrinter {
     for (OptionCategory *Category : SortedCategories) {
       // Hide empty categories for --help, but show for --help-hidden.
       const auto &CategoryOptions = CategorizedOptions[Category];
-      bool IsEmptyCategory = CategoryOptions.empty();
-      if (!ShowHidden && IsEmptyCategory)
+      if (CategoryOptions.empty())
         continue;
 
       // Print category information.
@@ -2488,12 +2487,6 @@ class CategorizedHelpPrinter : public HelpPrinter {
       else
         outs() << "\n";
 
-      // When using --help-hidden explicitly state if the category has no
-      // options associated with it.
-      if (IsEmptyCategory) {
-        outs() << "  This option category has no options.\n";
-        continue;
-      }
       // Loop over the options in the category and print.
       for (const Option *Opt : CategoryOptions)
         Opt->printOptionInfo(MaxArgLen);

llvm/test/tools/llvm-debuginfo-analyzer/cmdline.test

@@ -70,8 +70,6 @@ HELP-ALL:     =system                  -   Display PDB's MS system elements.
 HELP-ALL:     =typename                -   Include Parameters in templates.
 HELP-ALL:     =underlying              -   Underlying type for type definitions.
 HELP-ALL:     =zero                    -   Zero line numbers.
-HELP-ALL: Color Options:
-HELP-ALL:   This option category has no options.
 HELP-ALL: Compare Options:
 HELP-ALL: These control the view comparison.
 HELP-ALL:   --compare=<value>          - Elements to compare.
@@ -81,8 +79,6 @@ HELP-ALL:     =scopes                  -   Scopes.
 HELP-ALL:     =symbols                 -   Symbols.
 HELP-ALL:     =types                   -   Types.
 HELP-ALL:   --compare-context          - Add the view as compare context.
-HELP-ALL: General options:
-HELP-ALL:   This option category has no options.
 HELP-ALL: Generic Options:
 HELP-ALL:   -h                         - Alias for --help
 HELP-ALL:   --help                     - Display available options (--help-hidden for more)

llvm/unittests/Support/CommandLineTest.cpp

@@ -2301,4 +2301,29 @@ TEST(CommandLineTest, SubCommandGroups) {
   EXPECT_FALSE(SC3.OptionsMap.contains("opt12"));
 }
 
+TEST(CommandLineTest, HelpWithEmptyCategory) {
+  cl::ResetCommandLineParser();
+
+  cl::OptionCategory Category1("First Category");
+  cl::OptionCategory Category2("Second Category");
+  StackOption<int> Opt1("opt1", cl::cat(Category1));
+  StackOption<int> Opt2("opt2", cl::cat(Category2));
+  cl::HideUnrelatedOptions(Category2);
+
+  const char *args[] = {"prog"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(std::size(args), args, StringRef(),
+                                          &llvm::nulls()));
+  auto Output = interceptStdout(
+      []() { cl::PrintHelpMessage(/*Hidden=*/false, /*Categorized=*/true); });
+  EXPECT_EQ(std::string::npos, Output.find("First Category"))
+      << "An empty category should not be printed";
+
+  Output = interceptStdout(
+      []() { cl::PrintHelpMessage(/*Hidden=*/true, /*Categorized=*/true); });
+  EXPECT_EQ(std::string::npos, Output.find("First Category"))
+      << "An empty category should not be printed";
+
+  cl::ResetCommandLineParser();
+}
+
 } // anonymous namespace