Meta: Replace IPCMagicLinter with a python linter

Note that the IPC lint step can be removed from the CI workflow because
we no longer need a build in order to perform the lint, and IPC linting
is now covered by lint-ci.sh.

.github/workflows/lagom-template.yml

@@ -227,12 +227,3 @@ jobs:
             echo "$log_output"
             echo "Sanitizer errors happened while running tests; see the Test step above."
           fi
-
-      - name: Lints
-        if: ${{ inputs.os_name == 'Linux' && inputs.build_preset == 'Sanitizer' }}
-        working-directory: ${{ github.workspace }}
-        run: |
-          git ls-files '*.ipc' | xargs ./Build/bin/IPCMagicLinter
-        env:
-          ASAN_OPTIONS: 'strict_string_checks=1:check_initialization_order=1:strict_init_order=1:detect_stack_use_after_return=1:allocator_may_return_null=1'
-          UBSAN_OPTIONS: 'print_stacktrace=1:print_summary=1:halt_on_error=1'

Meta/Lagom/Tools/CMakeLists.txt

@@ -17,4 +17,3 @@ function(lagom_tool tool)
 endfunction()
 
 add_subdirectory(CodeGenerators)
-add_subdirectory(IPCMagicLinter)

Meta/Lagom/Tools/IPCMagicLinter/CMakeLists.txt

@@ -1,5 +0,0 @@
-set(SOURCES
-    main.cpp
-)
-
-lagom_tool(IPCMagicLinter LIBS LibMain)

Meta/Lagom/Tools/IPCMagicLinter/main.cpp

@@ -1,111 +0,0 @@
-/*
- * Copyright (c) 2021, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <AK/ByteString.h>
-#include <AK/HashMap.h>
-#include <AK/StringView.h>
-#include <AK/Vector.h>
-#include <LibCore/File.h>
-#include <LibMain/Main.h>
-
-// Exit code is bitwise-or of these values:
-static constexpr auto EXIT_COLLISION = 0x1;
-static constexpr auto EXIT_ERROR = 0x2;
-
-ErrorOr<int> ladybird_main(Main::Arguments arguments)
-{
-    if (arguments.argc < 3) {
-        warnln("Usage: {} path/to/some.ipc path/to/other.ipc [more ipc files ...]", arguments.strings[0]);
-        return EXIT_ERROR;
-    }
-
-    // Read files, compute their hashes, ignore collisions for now.
-    HashMap<u32, Vector<ByteString>, IdentityHashTraits<u32>> inverse_hashes;
-    bool had_errors = false;
-    for (auto filename : arguments.strings.slice(1)) {
-
-        auto const open_file = [](StringView filename) -> ErrorOr<NonnullOwnPtr<Core::InputBufferedFile>> {
-            auto file = TRY(Core::File::open(filename, Core::File::OpenMode::Read));
-            return Core::InputBufferedFile::create(move(file));
-        };
-
-        auto file_or_error = open_file(filename);
-
-        if (file_or_error.is_error()) {
-            warnln("Error: Cannot open '{}': {}", filename, file_or_error.error());
-            had_errors = true;
-            continue; // next file
-        }
-
-        auto file = file_or_error.release_value();
-
-        ByteString endpoint_name;
-
-        auto const read_lines = [&]() -> ErrorOr<void> {
-            while (TRY(file->can_read_line())) {
-                Array<u8, 1024> buffer;
-                auto line = TRY(file->read_line(buffer));
-
-                if (!line.starts_with("endpoint "sv))
-                    continue;
-                auto line_endpoint_name = line.substring_view("endpoint "sv.length());
-                if (!endpoint_name.is_empty()) {
-                    // Note: If there are three or more endpoints defined in a file, these errors will look a bit wonky.
-                    // However, that's fine, because it shouldn't happen in the first place.
-                    warnln("Error: Multiple endpoints in file '{}': Found {} and {}", filename, endpoint_name, line_endpoint_name);
-                    had_errors = true;
-                    continue; // next line
-                }
-                endpoint_name = line_endpoint_name;
-            }
-
-            return {};
-        };
-
-        auto maybe_error = read_lines();
-
-        if (maybe_error.is_error()) {
-            warnln("Error: Failed to read '{}': {}", filename, maybe_error.release_error());
-            had_errors = true;
-            continue; // next file
-        }
-        if (endpoint_name.is_empty()) {
-            // If this happens, this file probably needs to parse the endpoint name more carefully.
-            warnln("Error: Could not detect endpoint name in file '{}'", filename);
-            had_errors = true;
-            continue; // next file
-        }
-        u32 hash = endpoint_name.hash();
-        auto& files_with_hash = inverse_hashes.ensure(hash);
-        files_with_hash.append(filename);
-    }
-
-    // Report any collisions
-    bool had_collisions = false;
-    for (auto const& specific_collisions : inverse_hashes) {
-        if (specific_collisions.value.size() <= 1)
-            continue;
-        outln("Collision: Multiple endpoints use the magic number {}:", specific_collisions.key);
-        for (auto const& colliding_file : specific_collisions.value) {
-            outln("- {}", colliding_file);
-        }
-        had_collisions = true;
-    }
-
-    outln("Checked {} files, saw {} distinct magic numbers.", arguments.argc - 1, inverse_hashes.size());
-    if (had_collisions)
-        outln("Consider giving your new service a different name.");
-
-    if (had_errors)
-        warnln("Some errors were encountered. There may be endpoints with colliding magic numbers.");
-
-    int exit_code = 0;
-    if (had_collisions)
-        exit_code |= EXIT_COLLISION;
-    if (had_errors)
-        exit_code |= EXIT_ERROR;
-    return exit_code;
-}

Meta/Linters/lint_ipc.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2021, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
+# Copyright (c) 2026-present, the Ladybird developers.
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+import argparse
+import sys
+
+from collections import defaultdict
+from pathlib import Path
+from typing import Dict
+from typing import List
+
+sys.path.append(str(Path(__file__).resolve().parent.parent.parent))
+
+from Meta.Generators.string_hash import string_hash
+
+ENDPOINT_PREFIX = "endpoint "
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description="Check IPC endpoint files for magic-number collisions.")
+    parser.add_argument("ipc_files", nargs="+", help="IPC endpoint definition files")
+    args = parser.parse_args()
+
+    files_by_magic: Dict[int, List[str]] = defaultdict(list)
+    error_count = 0
+
+    def report_error(message: str) -> None:
+        nonlocal error_count
+        print(f"Error: {message}", file=sys.stderr)
+        error_count += 1
+
+    for path in args.ipc_files:
+        endpoint_name = ""
+
+        try:
+            with open(path, "r", encoding="utf-8") as ipc_file:
+                for line in ipc_file:
+                    line = line.strip()
+                    if not line.startswith(ENDPOINT_PREFIX):
+                        continue
+
+                    remaining = line[len(ENDPOINT_PREFIX) :]
+                    if endpoint_name:
+                        report_error(f"Multiple endpoints in file '{path}': Found {endpoint_name} and {remaining}")
+                        continue
+
+                    endpoint_name = remaining
+        except OSError as error:
+            report_error(f"Cannot open '{path}': {error}")
+            continue
+
+        if not endpoint_name:
+            report_error(f"Could not detect endpoint name in file '{path}'")
+            continue
+
+        files_by_magic[string_hash(endpoint_name)].append(path)
+
+    for magic, files in files_by_magic.items():
+        if len(files) <= 1:
+            continue
+
+        report_error(f"Collision: Multiple endpoints use the magic number {magic}:")
+        for colliding_file in files:
+            print(f"  - {colliding_file}")
+
+    print(f"Checked {len(args.ipc_files)} files, saw {len(files_by_magic)} distinct magic numbers.")
+
+    if error_count:
+        print(
+            "Some errors were encountered. There may be endpoints with colliding magic numbers.",
+            file=sys.stderr,
+        )
+
+    return error_count
+
+
+if __name__ == "__main__":
+    sys.exit(main())

Meta/lint-ci.sh

@@ -33,15 +33,11 @@ for cmd in \
     fi
 done
 
-if [ -x ./Build/lagom/bin/IPCMagicLinter ]; then
+if { git ls-files '*.ipc' | xargs Meta/Linters/lint_ipc.py; }; then
-    if { git ls-files '*.ipc' | xargs ./Build/lagom/bin/IPCMagicLinter; }; then
+    echo -e "[${GREEN}OK${NC}]: Meta/Linters/lint_ipc.py"
-        echo -e "[${GREEN}OK${NC}]: IPCMagicLinter (in Meta/lint-ci.sh)"
-    else
-        echo -e "[${BOLD_RED}FAIL${NC}]: IPCMagicLinter (in Meta/lint-ci.sh)"
-        ((FAILURES+=1))
-    fi
 else
-    echo -e "[${GREEN}SKIP${NC}]: IPCMagicLinter (in Meta/lint-ci.sh)"
+    echo -e "[${BOLD_RED}FAIL${NC}]: Meta/Linters/lint_ipc.py"
+    ((FAILURES+=1))
 fi
 
 if Meta/Linters/lint_clang_format.py --overwrite-inplace "$@" && git diff --exit-code -- ':*.cpp' ':*.h' ':*.mm'; then