Bazel: general improvements. (#1043)

* Bazel: general improvements.

Improve the Bazel build. Attempt to fix previous errors recorded while
trying to publish ftxui in the Bazel Central Registry:
- https://github.com/bazelbuild/bazel-central-registry/pull/4485
- https://buildkite.com/bazel/bcr-presubmit/builds/13601#01968b61-f5b2-4d16-94d0-c87a03a1a23b

Test against "recent" platforms
-------------------------------

Previously, I got the error:
```
gcc: error: unrecognized command line option '-std-c++20'; did you mean '-std-c++2a'?
```
This was due to using old distribution like ubuntu 2004. Test against
newer platforms only to avoid GCC version<-9.x.y

Downgrade gtest version.
------------------------

I suspect this caused the Bazel Central Registry error:
```
file:///workdir/modules/googletest/1.15.2/MODULE.bazel:68:20: name 'use_repo_rule' is not defined
```
Specifying using bazelmod fixes the issue. Thanks @robinlinden

Tag gtest as dev_dependency
---------------------------

Presumably, this should avoid dependants to fetch it?

Enable --features-layering_check
--------------------------------

Aka clang `-Wprivate-header`. Fix the encountered errors.

Use clang in the CI
-------------------

The CI was defining clang/gcc in the matrix, but was not using it. Fix
the bug.

.bazelrc

@@ -0,0 +1,7 @@
+build --features=layering_check
+build --enable_bzlmod
+
+build --enable_platform_specific_config
+build:linux --cxxopt=-std=c++20
+build:macos --cxxopt=-std=c++20
+build:windows --cxxopt=-std:c++20

.bcr/presubmit.yml

@@ -1,21 +1,36 @@
 matrix:
-  platform:
+  bazel:
-  - centos7
+    - 7.x
-  - debian10
+    - 8.x
-  - ubuntu2004
+    - rolling
-  - macos
+  unix_platform:
-  - windows
+    - debian11
-  bazel: [6.x, 7.x, 8.x]
+    - ubuntu2204
+    - macos
+    - macos_arm64
+  win_platform:
+    - windows
+
 tasks:
-  verify_targets:
+
-    name: Build and test.
+  unix_test:
-    platform: ${{ platform }}
+    name: Verify build targets on Unix
+    platform: ${{ unix_platform }}
     bazel: ${{ bazel }}
+    build_flags:
+    - --cxxopt=-std=c++20
     build_targets:
-    - '@ftxui//:ftxui'
-    - '@ftxui//:screen'
     - '@ftxui//:dom'
     - '@ftxui//:component'
-    test_targets:
+    - '@ftxui//:screen'
-    - '@ftxui//:tests'
 
+  windows_test:
+    name: Verify build targets
+    platform: ${{ win_platform }}
+    bazel: ${{ bazel }}
+    build_flags:
+    - --cxxopt=/std:c++20
+    build_targets:
+    - '@ftxui//:dom'
+    - '@ftxui//:component'
+    - '@ftxui//:screen'

.github/workflows/build.yaml

@@ -14,25 +14,30 @@ on:
 jobs:
 
   test_bazel:
-    name: "Bazel, ${{ matrix.compiler }}, ${{ matrix.os }}"
+    name: "Bazel, ${{ matrix.cxx }}, ${{ matrix.os }}"
     strategy:
       fail-fast: false
       matrix:
         include:
           - os: ubuntu-latest
-            compiler: gcc
+            cxx: g++
+            cc: gcc
 
           - os: ubuntu-latest
-            compiler: llvm
+            cxx: clang++
+            cc: clang
 
           - os: macos-latest
-            compiler: llvm
+            cxx: g++
+            cc: gcc
 
           - os: macos-latest
-            compiler: gcc
+            cxx: clang++
+            cc: clang
 
           - os: windows-latest
-            compiler: cl
+            cxx: cl
+            cc: cl
 
     runs-on: ${{ matrix.os }}
     steps:
@@ -40,10 +45,16 @@ jobs:
         uses: actions/checkout@v3
 
       - name: "Build with Bazel"
+        env:
+          CC: ${{ matrix.cc }}
+          CXX: ${{ matrix.cxx }}
         run: bazel build ...
 
       - name: "Tests with Bazel"
-        run: bazel run tests
+        env:
+          CC: ${{ matrix.cc }}
+          CXX: ${{ matrix.cxx }}
+        run: bazel test --test_output=all ...
 
   test_cmake:
     name: "CMake, ${{ matrix.compiler }}, ${{ matrix.os }}"

BUILD.bazel

@@ -12,23 +12,19 @@
 load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_test")
 load(":bazel/ftxui.bzl", "ftxui_cc_library")
 load(":bazel/ftxui.bzl", "generate_examples")
-load(":bazel/ftxui.bzl", "cpp20")
 load(":bazel/ftxui.bzl", "windows_copts")
 load(":bazel/ftxui.bzl", "pthread_linkopts")
 
-package(default_visibility = ["//visibility:public"])
+# A meta target depending on all of the ftxui submodules.
+# Note that component depends on dom and screen, so ftxui is just an alias for 
+# component.
+# ┌component──┐
+# │┌dom──────┐│
+# ││┌screen─┐││
+# └┴┴───────┴┴┘
+alias(name = "ftxui", actual = ":component")
 
-# A meta target that depends on all the ftxui sub modules.
+# @ftxui:screen is a module that provides a screen buffer and color management
-alias(
-    name = "ftxui",
-    # Note that :component depends on :dom, which depends on :screen. Bazel
-    # doesn't really support "public" and "private" dependencies. They are all
-    # public. This is equivalent to depending on all the submodules.
-    actual = ":component",
-    visibility = ["//visibility:public"],
-)
-
-# ftxui:screen is a module that provides a screen buffer and color management
 # for terminal applications. A screen is a 2D array of cells, each cell can
 # contain a glyph, a color, and other attributes. The library also provides
 # functions to manipulate the screen.
@@ -60,7 +56,7 @@ ftxui_cc_library(
     ],
 )
 
-# ftxui:dom is a library that provides a way to create and manipulate a
+# @ftxui:dom is a library that provides a way to create and manipulate a
 # "document" that can be rendered to a screen. The document is a tree of nodes.
 # Nodes can be text, layouts, or various decorators. Users needs to compose
 # nodes to create a document. A document is responsive to the size of the
@@ -130,7 +126,7 @@ ftxui_cc_library(
     deps = [":screen"],
 )
 
-# ftxui:component is a library to create "dynamic" component renderering and
+# @ftxui:component is a library to create "dynamic" component renderering and
 # updating a ftxui::dom document on the screen. It is a higher level API than
 # ftxui:dom.
 #
@@ -167,6 +163,13 @@ ftxui_cc_library(
         "src/ftxui/component/terminal_input_parser.hpp",
         "src/ftxui/component/util.cpp",
         "src/ftxui/component/window.cpp",
+
+        # Private header from ftxui:dom.
+        "src/ftxui/dom/node_decorator.hpp",
+
+        # Private header from ftxui:screen.
+        "src/ftxui/screen/string_internal.hpp",
+        "src/ftxui/screen/util.hpp",
     ],
     hdrs = [
         "include/ftxui/component/animation.hpp",
@@ -182,7 +185,10 @@ ftxui_cc_library(
         "include/ftxui/component/task.hpp",
     ],
     linkopts = pthread_linkopts(),
-    deps = [":dom"],
+    deps = [
+        ":dom",
+        ":screen",
+    ],
 )
 
 # FTXUI's tests
@@ -205,7 +211,6 @@ cc_test(
         "src/ftxui/component/resizable_split_test.cpp",
         "src/ftxui/component/slider_test.cpp",
         "src/ftxui/component/terminal_input_parser_test.cpp",
-        "src/ftxui/component/terminal_input_parser_test_fuzzer.cpp",
         "src/ftxui/component/toggle_test.cpp",
         "src/ftxui/dom/blink_test.cpp",
         "src/ftxui/dom/bold_test.cpp",
@@ -233,6 +238,17 @@ cc_test(
         "src/ftxui/screen/string_test.cpp",
         "src/ftxui/util/ref_test.cpp",
 
+        # Private header from ftxui:screen for string_test.cpp.
+        "src/ftxui/screen/string_internal.hpp",
+
+        # Private header from ftxui::component for
+        # terminal_input_parser_test.cpp.
+        "src/ftxui/component/terminal_input_parser.hpp",
+
+        # Private header from ftxui::dom for
+        # flexbox_helper_test.cpp.
+        "src/ftxui/dom/flexbox_helper.hpp",
+
         # TODO: Enable the two tests timing out with Bazel:
         # - "src/ftxui/component/screen_interactive_test.cpp",
         # - "src/ftxui/dom/selection_test.cpp",
@@ -241,9 +257,12 @@ cc_test(
         "include",
         "src",
     ],
-    copts = cpp20() + windows_copts(),
+    copts = windows_copts(),
     deps = [
-        "//:ftxui",
+        ":screen",
+        ":dom",
+        ":component",
+        "@googletest//:gtest",
         "@googletest//:gtest_main",
     ],
 )

MODULE.bazel

@@ -1,9 +1,13 @@
-# FTXUI Module.
+# FTXUI module.
-module(name = "ftxui", version = "6.1.8", compatibility_level = 6)
+module(
+    name = "ftxui",
+    version = "6.1.8",
+    compatibility_level = 6,
+)
 
-# Build deps.
+# Build dependencies.
 bazel_dep(name = "rules_cc", version = "0.1.1")
-bazel_dep(name = "platforms", version = "0.0.11")
+bazel_dep(name = "platforms", version = "0.0.10")
 
-# Test deps.
+# Test dependencies.
-bazel_dep(name = "googletest", version = "1.16.0.bcr.1")
+bazel_dep(name = "googletest", version = "1.14.0.bcr.1", dev_dependency = True)

bazel/ftxui.bzl

@@ -1,24 +1,7 @@
 # ftxui_common.bzl
 
 load("@rules_cc//cc:defs.bzl", "cc_library")
-
+load("@rules_cc//cc:defs.bzl", "cc_binary")
-def cpp17():
-    return select({
-        "@rules_cc//cc/compiler:msvc-cl": ["/std:c++17"],
-        "@rules_cc//cc/compiler:clang-cl": ["/std:c++17"],
-        "@rules_cc//cc/compiler:clang": ["-std=c++17"],
-        "@rules_cc//cc/compiler:gcc": ["-std=c++17"],
-        "//conditions:default": ["-std=c++17"],
-    })
-
-def cpp20():
-    return select({
-        "@rules_cc//cc/compiler:msvc-cl": ["/std:c++20"],
-        "@rules_cc//cc/compiler:clang-cl": ["/std:c++20"],
-        "@rules_cc//cc/compiler:clang": ["-std=c++20"],
-        "@rules_cc//cc/compiler:gcc": ["-std=c++20"],
-        "//conditions:default": ["-std=c++20"],
-    })
 
 # Microsoft terminal is a bit buggy ¯\_(ツ)_/¯ and MSVC uses bad defaults.
 def windows_copts():
@@ -45,7 +28,8 @@ def windows_copts():
       # This
       # - Replace missing font symbols by others.
       # - Reduce screen position pooling frequency to deals against a Microsoft
-      #   race condition. This was fixed in 2020, but clients never not updated.
+      #   race condition. This was fixed in 2020, but clients are still using
+      #   old versions.
       #   - https://github.com/microsoft/terminal/pull/7583
       #   - https://github.com/ArthurSonzogni/FTXUI/issues/136
       "-DFTXUI_MICROSOFT_TERMINAL_FALLBACK",
@@ -71,8 +55,8 @@ def pthread_linkopts():
 
 def ftxui_cc_library(
         name,
-        srcs,
+        srcs = [],
-        hdrs,
+        hdrs = [],
         linkopts = [],
         deps = []):
 
@@ -88,12 +72,13 @@ def ftxui_cc_library(
             "include",
             "src",
         ],
-        copts = cpp17() + windows_copts(),
+        copts = windows_copts(),
         visibility = ["//visibility:public"],
     )
 
 # Compile all the examples in the examples/ directory.
-# This is useful to check the Bazel is synchronized with CMake definitions.
+# This is useful to check the Bazel is always synchronized against CMake
+# definitions.
 def generate_examples():
     cpp_files = native.glob(["examples/**/*.cpp"])
 
@@ -107,9 +92,13 @@ def generate_examples():
         # Turn "examples/component/button.cpp" → "example_component_button"
         name = src.replace("/", "_").replace(".cpp", "")
 
-        native.cc_binary(
+        cc_binary(
             name = name,
             srcs = [src],
-            deps = ["//:component"],
+            deps = [
-            copts = cpp20() + windows_copts(),
+              ":component",
+              ":dom",
+              ":screen",
+            ],
+            copts = windows_copts(),
         )

tools/test_bazel.sh

@@ -0,0 +1,18 @@
+# This script tests the project with different versions of Bazel and compilers
+# locally. This avoids waiting on the CI to run the tests.
+
+for ver in \
+  "6.0.0" \
+  "7.0.0" \
+  "8.0.0"
+do
+  for cc in \
+    "gcc" \
+    "clang"
+    do
+      echo "=== Testing with Bazel ${ver} with ${cc} ==="
+      USE_BAZEL_VERSION=${ver} CC=${cc} bazel clean --expunge
+      USE_BAZEL_VERSION=${ver} CC=${cc} bazel build //...
+      USE_BAZEL_VERSION=${ver} CC=${cc} bazel test //...
+    done
+  done