From 00ab97b1bc07206be4d05547fe44bfd7afd607dc Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Fri, 6 Dec 2024 14:24:58 +0100 Subject: Documentation: add comparison of build systems We're contemplating whether to eventually replace our build systems with a build system that is easier to use. Add a comparison of build systems to our technical documentation as a baseline for discussion. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- Documentation/technical/build-systems.txt | 224 ++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) create mode 100644 Documentation/technical/build-systems.txt (limited to 'Documentation/technical') diff --git a/Documentation/technical/build-systems.txt b/Documentation/technical/build-systems.txt new file mode 100644 index 0000000000..d9dafb407c --- /dev/null +++ b/Documentation/technical/build-systems.txt @@ -0,0 +1,224 @@ += Build Systems + +The build system is the primary way for both developers and system integrators +to interact with the Git project. As such, being easy to use and extend for +those who are not directly developing Git itself is just as important as other +requirements we have on any potential build system. + +This document outlines the different requirements that we have for the build +system and then compares available build systems using these criteria. + +== Requirements + +The following subsections present a list of requirements that we have for any +potential build system. Sections are sorted by decreasing priority. + +=== Platform support + +The build system must have support for all of our platforms that we continually +test against as outlined by our platform support policy. These platforms are: + + - Linux + - Windows + - macOS + +Furthermore, the build system should have support for the following platforms +that generally have somebody running test pipelines against regularly: + + - AIX + - FreeBSD + - NetBSD + - NonStop + - OpenBSD + +The platforms which must be supported by the tool should be aligned with our +[platform support policy](platform-support.txt). + +=== Auto-detection of supported features + +The build system must support auto-detection of features which are or aren't +available on the current platform. Platform maintainers should not be required +to manually configure the complete build. + +Auto-detection of the following items is considered to be important: + + - Check for the existence of headers. + - Check for the existence of libraries. + - Check for the existence of exectuables. + - Check for the runtime behavior of specific functions. + - Check for specific link order requirements when multiple libraries are + involved. + +=== Ease of use + +The build system should be both easy to use and easy to extend. While this is +naturally a subjective metric it is likely not controversial to say that some +build systems are considerably harder to use than others. + +=== IDE support + +The build system should integrate with well-known IDEs. Well-known IDEs include: + + - Microsoft Visual Studio + - Visual Studio Code + - Xcode + +There are four levels of support: + + - Native integration into the IDE. + - Integration into the IDE via a plugin. + - Integration into the IDE via generating a project description with the build + system. + - No integration. + +Native integration is preferable, but integration via either a plugin or by +generating a project description via the build system are considered feasible +alternatives. + +Another important distinction is the level of integration. There are two +features that one generally wants to have: + + - Integration of build targets. + - Automatic setup of features like code completion with detected build + dependencies. + +The first bullet point is the bare minimum, but is not sufficient to be +considered proper integration. + +=== Out-of-tree builds + +The build system should support out-of-tree builds. Out-of-tree builds allow a +developer to configure multiple different build directories with different +configuration, e.g. one "debug" build and one "release" build. + +=== Cross-platform builds + +The build system should support cross-platform builds, e.g. building for arm on +an x86-64 host. + +=== Language support + +The following languages and toolchains are of relevance and should be supported +by the build system: + + - C: the primary compiled language used by Git, must be supported. Relevant + toolchains are GCC, Clang and MSVC. + - Rust: candidate as a second compiled lanugage, should be supported. Relevant + toolchains is the LLVM-based rustc. + +Built-in support for the respective languages is preferred over support that +needs to be wired up manually to avoid unnecessary complexity. Native support +includes the following features: + + - Compiling objects. + - Dependency tracking. + - Detection of available features. + - Discovery of relevant toolchains. + - Linking libraries and executables. + - Templating placeholders in scripts. + +=== Test integration + +It should be possible to integrate tests into the build system such that it is +possible to build and test Git within the build system. Features which are nice +to have: + + - Track build-time dependencies for respective tests. Unit tests have + different requirements than integration tests. + - Allow filtering of which tests to run. + - Allow running tests such that utilities like `test_pause` or `debug` work. + +== Comparison + +The following list of build systems are considered: + +- GNU Make +- autoconf +- CMake +- Meson + +=== GNU Make + +- Platform support: ubitquitous on all platforms, but not well-integrated into Windows. +- Auto-detection: no built-in support for auto-detection of features. +- Ease of use: easy to use, but discovering available options is hard. Makefile + rules can quickly get out of hand once reaching a certain scope. +- IDE support: execution of Makefile targets is supported by many IDEs +- Out-of-tree builds: supported in theory, not wired up in practice. +- Cross-platform builds: supported in theory, not wired up in practice. +- Language support: + - C: Limited built-in support, many parts need to be wired up manually. + - Rust: No built-in support, needs to be wired up manually. +- Test integration: partially supported, many parts need to be wired up + manually. + +=== autoconf + +- Platform support: ubiquitous on all platforms, but not well-integrated into Windows. +- Auto-detection: supported. +- Ease of use: easy to use, discovering available options is comparatively + easy. The autoconf syntax is prohibitively hard to extend though due to its + complex set of interacting files and the hard-to-understand M4 language. +- IDE support: no integration into IDEs at generation time. The generated + Makefiles have the same level of support as GNU Make. +- Out-of-tree builds: supported in theory, not wired up in practice. +- Cross-platform builds: supported. +- Language support: + - C: Limited built-in support, many parts need to be wired up manually. + - Rust: No built-in support, needs to be wired up manually. +- Test integration: partially supported, many parts need to be wired up + manually. + +=== CMake + +- Platform support: not as extensive as GNU Make or autoconf, but all major + platforms are supported. + - AIX + - Cygwin + - FreeBSD + - Linux + - OpenBSD + - Solaris + - Windows + - macOS +- Ease of use: easy to use, discovering available options is not always + trivial. The scripting language used by CMake is somewhat cumbersome to use, + but extending CMake build instructions is doable. +- IDE support: natively integrated into Microsoft Visual Studio. Can generate + project descriptions for Xcode. An extension is available for Visual Studio + Code. Many other IDEs have plugins for CMake. +- Out-of-tree builds: supported. +- Cross-platform builds: supported. +- Language support: + - C: Supported for GCC, Clang, MSVC and other toolchains. + - Rust: No built-in support, needs to be wired up manually. +- Test integration: supported, even though test dependencies are a bit + cumbersome to use via "test fixtures". Interactive test runs are not + supported. + +=== Meson + +- Platform: not as extensive as GNU Make or autoconf, but all major platforms + and some smaller ones are supported. + - AIX + - Cygwin + - DragonflyBSD + - FreeBSD + - Haiku + - Linux + - NetBSD + - OpenBSD + - Solaris + - Windows + - macOS +- Ease of use: easy to use, discovering available options is easy. The + scripting language is straight-forward to use. +- IDE support: Supports generating build instructions for Xcode and Microsoft + Visual Studio, a plugin exists for Visual Studio Code. +- Out-of-tree builds: supported. +- Cross-platform builds: supported. +- Language support: + - C: Supported for GCC, Clang, MSVC and other toolchains. + - Rust: Supported for rustc. +- Test integration: supported. Interactive tests are supported starting with + Meson 1.5.0 via the `--interactive` flag. -- cgit v1.2.3 From 88e08b92e9a55fa453d44b26061a6a67a7eefafc Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Fri, 27 Dec 2024 14:59:35 +0100 Subject: Documentation: refactor "api-index.sh" for out-of-tree builds The "api-index.sh" script generates an index of API-related documentation. The script does not handle out-of-tree builds and thus cannot be used easily by Meson. Refactor it to be independent of locations by both accepting a source directory where the API docs live as well as a path to an output file. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- Documentation/Makefile | 2 +- Documentation/technical/api-index.sh | 19 +++++++++++++++---- 2 files changed, 16 insertions(+), 5 deletions(-) (limited to 'Documentation/technical') diff --git a/Documentation/Makefile b/Documentation/Makefile index 4f152077dd..b2d146c44f 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -367,7 +367,7 @@ user-manual.xml: user-manual.txt $(ASCIIDOC_DEPS) technical/api-index.txt: technical/api-index-skel.txt \ technical/api-index.sh $(patsubst %,%.txt,$(API_DOCS)) - $(QUIET_GEN)cd technical && '$(SHELL_PATH_SQ)' ./api-index.sh + $(QUIET_GEN)'$(SHELL_PATH_SQ)' technical/api-index.sh ./technical ./technical/api-index.txt technical/%.html: ASCIIDOC_EXTRA += -a git-relative-html-prefix=../ $(patsubst %,%.html,$(API_DOCS) technical/api-index $(TECH_DOCS)): %.html : %.txt \ diff --git a/Documentation/technical/api-index.sh b/Documentation/technical/api-index.sh index 9c3f4131b8..2964885574 100755 --- a/Documentation/technical/api-index.sh +++ b/Documentation/technical/api-index.sh @@ -1,6 +1,17 @@ #!/bin/sh +if test $# -ne 2 +then + echo >&2 "USAGE: $0 " + exit 1 +fi + +SOURCE_DIR="$1" +OUTPUT="$2" + ( + cd "$SOURCE_DIR" + c=//////////////////////////////////////////////////////////////// skel=api-index-skel.txt sed -e '/^\/\/ table of contents begin/q' "$skel" @@ -18,11 +29,11 @@ done echo "$c" sed -n -e '/^\/\/ table of contents end/,$p' "$skel" -) >api-index.txt+ +) >"$OUTPUT"+ -if test -f api-index.txt && cmp api-index.txt api-index.txt+ >/dev/null +if test -f "$OUTPUT" && cmp "$OUTPUT" "$OUTPUT"+ >/dev/null then - rm -f api-index.txt+ + rm -f "$OUTPUT"+ else - mv api-index.txt+ api-index.txt + mv "$OUTPUT"+ "$OUTPUT" fi -- cgit v1.2.3 From bcf7edee09e8f9c1779fafa953832f63e9a23545 Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Fri, 27 Dec 2024 14:59:37 +0100 Subject: meson: generate articles While the Meson build system already knows to generate man pages and our user manual, it does not yet generate the random assortment of articles that we have. Plug this gap. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- Documentation/howto/meson.build | 62 ++++++++++++++++++++++++++++++++++ Documentation/meson.build | 36 ++++++++++++++++++++ Documentation/technical/meson.build | 66 +++++++++++++++++++++++++++++++++++++ 3 files changed, 164 insertions(+) create mode 100644 Documentation/howto/meson.build create mode 100644 Documentation/technical/meson.build (limited to 'Documentation/technical') diff --git a/Documentation/howto/meson.build b/Documentation/howto/meson.build new file mode 100644 index 0000000000..c023c10416 --- /dev/null +++ b/Documentation/howto/meson.build @@ -0,0 +1,62 @@ +howto_sources = [ + 'coordinate-embargoed-releases.txt', + 'keep-canonical-history-correct.txt', + 'maintain-git.txt', + 'new-command.txt', + 'rebase-from-internal-branch.txt', + 'rebuild-from-update-hook.txt', + 'recover-corrupted-blob-object.txt', + 'recover-corrupted-object-harder.txt', + 'revert-a-faulty-merge.txt', + 'revert-branch-rebase.txt', + 'separating-topic-branches.txt', + 'setup-git-server-over-http.txt', + 'update-hook-example.txt', + 'use-git-daemon.txt', + 'using-merge-subtree.txt', + 'using-signed-tag-in-pull-request.txt', +] + +howto_index = custom_target( + command: [ + shell, + meson.current_source_dir() / 'howto-index.sh', + '@INPUT@', + ], + env: script_environment, + capture: true, + input: howto_sources, + output: 'howto-index.txt', +) + +custom_target( + command: asciidoc_html_options, + input: howto_index, + output: 'howto-index.html', + depends: documentation_deps, + install: true, + install_dir: get_option('datadir') / 'doc/git-doc', +) + +foreach howto : howto_sources + howto_stripped = custom_target( + command: [ + find_program('sed'), + '-e', + '1,/^$/d', + '@INPUT@', + ], + input: howto, + output: fs.stem(howto) + '.stripped', + capture: true, + ) + + custom_target( + command: asciidoc_html_options, + input: howto_stripped, + output: fs.stem(howto_stripped.full_path()) + '.html', + depends: documentation_deps, + install: true, + install_dir: get_option('datadir') / 'doc/git-doc/howto', + ) +endforeach diff --git a/Documentation/meson.build b/Documentation/meson.build index 404cb20d10..8c6ff0bce1 100644 --- a/Documentation/meson.build +++ b/Documentation/meson.build @@ -413,4 +413,40 @@ if get_option('docs').contains('html') install: true, install_dir: get_option('datadir') / 'doc/git-doc', ) + + articles = [ + 'DecisionMaking.txt', + 'MyFirstContribution.txt', + 'MyFirstObjectWalk.txt', + 'ReviewingGuidelines.txt', + 'SubmittingPatches', + 'ToolsForGit.txt', + 'git-bisect-lk2009.txt', + 'git-tools.txt', + ] + + foreach article : articles + custom_target( + command: asciidoc_common_options + [ + '--backend=' + asciidoc_html, + '--out-file=@OUTPUT@', + '@INPUT@', + ], + input: article, + output: fs.stem(article) + '.html', + depends: documentation_deps, + install: true, + install_dir: get_option('datadir') / 'doc/git-doc', + ) + endforeach + + asciidoc_html_options = asciidoc_common_options + [ + '--backend=' + asciidoc_html, + '--out-file=@OUTPUT@', + '--attribute', 'git-relative-html-prefix=../', + '@INPUT@', + ] + + subdir('howto') + subdir('technical') endif diff --git a/Documentation/technical/meson.build b/Documentation/technical/meson.build new file mode 100644 index 0000000000..21dfb8b5c9 --- /dev/null +++ b/Documentation/technical/meson.build @@ -0,0 +1,66 @@ +api_docs = [ + 'api-error-handling.txt', + 'api-merge.txt', + 'api-parse-options.txt', + 'api-simple-ipc.txt', + 'api-trace2.txt', +] + +articles = [ + 'bitmap-format.txt', + 'build-systems.txt', + 'bundle-uri.txt', + 'commit-graph.txt', + 'directory-rename-detection.txt', + 'hash-function-transition.txt', + 'long-running-process-protocol.txt', + 'multi-pack-index.txt', + 'packfile-uri.txt', + 'pack-heuristics.txt', + 'parallel-checkout.txt', + 'partial-clone.txt', + 'platform-support.txt', + 'racy-git.txt', + 'reftable.txt', + 'remembering-renames.txt', + 'repository-version.txt', + 'rerere.txt', + 'scalar.txt', + 'send-pack-pipeline.txt', + 'shallow.txt', + 'sparse-checkout.txt', + 'sparse-index.txt', + 'trivial-merge.txt', + 'unit-tests.txt', +] + +api_index = custom_target( + command: [ + shell, + meson.current_source_dir() / 'api-index.sh', + meson.current_source_dir(), + '@OUTPUT@', + ], + env: script_environment, + input: api_docs, + output: 'api-index.txt', +) + +custom_target( + command: asciidoc_html_options, + input: api_index, + output: 'api-index.html', + depends: documentation_deps, + install: true, + install_dir: get_option('datadir') / 'doc/git-doc/technical', +) + +foreach article : api_docs + articles + custom_target( + command: asciidoc_html_options, + input: article, + output: fs.stem(article) + '.html', + install: true, + install_dir: get_option('datadir') / 'doc/git-doc/technical', + ) +endforeach -- cgit v1.2.3 From 1dca492eddf4f45cbeac4c7a0d77553211489593 Mon Sep 17 00:00:00 2001 From: Sam James Date: Tue, 14 Jan 2025 14:47:10 +0000 Subject: meson: fix missing deps for technical articles We need an explicit `depends: documentation_deps` so that all of our Documentation targets know they require asciidoc.conf. This shows up as parallel build failures with it not yet being available. Other targets look OK already. Signed-off-by: Sam James Acked-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- Documentation/technical/meson.build | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation/technical') diff --git a/Documentation/technical/meson.build b/Documentation/technical/meson.build index 21dfb8b5c9..3a65ee59b3 100644 --- a/Documentation/technical/meson.build +++ b/Documentation/technical/meson.build @@ -60,6 +60,7 @@ foreach article : api_docs + articles command: asciidoc_html_options, input: article, output: fs.stem(article) + '.html', + depends: documentation_deps, install: true, install_dir: get_option('datadir') / 'doc/git-doc/technical', ) -- cgit v1.2.3