Require CMake 3.18 (2020-07-15) or newer, up from 3.7 (2016-11-11)
prior to this patch.
This requirement also applies to the distributed `curl-config.cmake`.
To allow dropping compatibility code maintained for old versions, and to
use features which were unpractical in separate code paths. Also to make
testing, documentation and development easier, CI builds faster due to
CMake performance improvements over time. (e.g. integration tests on
macOS run 8x faster (10 minutes is now under 1.5m) in CI, 2.5x faster on
Windows.)
CMake offers pre-built binaries for major platforms. They work without
an install step, just by unpacking and pointing the cmake command to
them. Making upgrades easy in many cases:
https://cmake.org/download/https://cmake.org/files/https://github.com/Kitware/CMake/releases
CMake 3.18 brings these feature as generally available when building or
consuming curl/libcurl:
LTO support, improved performance, `pkg-config` and interface target
support, `OBJECT` target (for faster libcurl builds), modern invocation
with `-S`/`-B` options, better support for custom linker options,
FetchContent, `GnuTLS::GnuTLS` target, `--verbose` and `--install`
options, `CMAKE_GENERATOR` env, last but not least unity mode and Ninja
generator.
For maximum build speed, use:
`-DCMAKE_UNITY_BUILD=ON -DCURL_DROP_UNUSED=ON`
As for deprecations, C++11 is required to build CMake itself, which may
be a limit on some platforms. autotools continues to cover them.
Follow-up to 9bcdfb3809#20408
Follow-up to a7c974e038#19902
Follow-up to dfbe035c8b#10161
Discussion: https://github.com/curl/curl/discussions/18704Closes#20407
- add support for separate provider / consumer cmake options in
`find_package` tests. To help test more integration scenarios.
Refs: #20784#20729#20764
- dump generated curl config files in `find_package` tests.
(cmake CONFIG source, `libcurl.pc`, `curl-config`.
- test.sh: use `sha256sum` (was: `openssl`).
Closes#20773
Rework the way curl's custom Find modules advertise their properties.
Before this patch, Find modules returned detected dependency properties
(header dirs, libs, libdirs, C flags, etc.) via global variables. curl's
main `CMakeLists.txt` copied their values into global lists, which it
later applied to targets. This solution worked internally, but it was
unsuited for the public, distributed `CURLConfig.cmake` and publishing
curl's Find modules with it, due to polluting the namespace of consumer
projects. It's also impractical to apply the many individual variables
to every targets depending on libcurl.
To allow using Find modules in consumer projects, this patch makes them
define as imported interface targets, named `CURL::<dependency>`. Then
store dependency information as target properties. It avoids namespace
pollution and makes the dependency information apply automatically
to all targets using `CURL::libcurl_static`.
Find modules continue to return `*_FOUND` and `*_VERSION` variables.
For dependencies detected via `pkg-config`, CMake 3.16+ is recommended.
Older CMake versions have a varying degree of support for
propagating/handling library directories. This may cause issues in envs
where dependencies reside in non-system locations and detected via
`pkg-config` (e.g. macOS + Homebrew). Use `CURL_USE_PKGCONFIG=OFF`
to fix these issues. Or upgrade to newer CMake, or link libcurl
dynamically.
Also:
- re-enable `pkg-config` for old cmake `find_library()` integration
tests.
- make `curlinfo` build after these changes.
- distribute local Find modules.
- export the raw list of lib dependencies via `CURL_LIBRARIES_PRIVATE`.
- `CURLconfig.cmake`: use curl's Find modules to detect dependencies in
the consumer env.
- add custom property to target property debug function.
- the curl build process no longer modifies `CMAKE_C_FLAGS`.
Follow-up to e86542038d#17047
Ref: #14930
Ref: https://github.com/libssh2/libssh2/pull/1535
Ref: https://github.com/libssh2/libssh2/pull/1571
Ref: https://github.com/libssh2/libssh2/pull/1581
Ref: https://github.com/libssh2/libssh2/pull/1623Closes#16973
By micromanaging the project dependency and its inclusion into the test
project. It feels like an awkward construct, but perhaps better than
nothing.
It's also fragile because it's a static build with no assistance from
the external project (curl in this case). Mitigated in test by disabling
all dependencies and some features.
Since there is no special core cmake logic to be tested here, in CI
the test is tested really. To keep CI jobs at minimum, only add 3 of
them, taking 42s in total. (All 6 would take 270s.)
Follow-up to e2a23d5d0d#17203Closes#18208
Tests with old cmake are slow. (no Ninja, no unity, and running slower
than recent versions.)
It also revealed that 3.7.2 2017-01-13 is too old to consume curl via
`find_package()` due to:
```
CMake Error at bld-curl/_pkg/lib/cmake/CURL/CURLConfig.cmake:69 (add_library):
add_library cannot create ALIAS target "CURL::libcurl" because target
"CURL::libcurl_shared" is IMPORTED.
Call Stack (most recent call first):
CMakeLists.txt:48 (find_package)
CMake Error at bld-curl/_pkg/lib/cmake/CURL/CURLConfig.cmake:69 (add_library):
add_library cannot create ALIAS target "CURL::libcurl" because target
"CURL::libcurl_shared" is IMPORTED.
Call Stack (most recent call first):
CMakeLists.txt:49 (find_package)
```
The mitigation for this issue requires 3.11.
Also:
- rename a few existing envs to use the `TEST_` prefix.
- make the `find_package` test provider stage verbose.
- fix issue when consuming with cmake 3.7.2 (all platforms):
```
CMake Error at /home/runner/cmake-3.7.2-Linux-x86_64/share/cmake-3.7/Modules/CMakeFindDependencyMacro.cmake:25 (message):
Invalid arguments to find_dependency. VERSION is empty
Call Stack (most recent call first):
bld-curl/_pkg/lib/cmake/CURL/CURLConfig.cmake:52 (find_dependency)
CMakeLists.txt:48 (find_package)
```
Ref: https://github.com/curl/curl/actions/runs/14906066962/job/41868621979?pr=17293#step:9:1199Closes#17293
- GHA: add cmake integration tests for Windows.
- make them run faster with prefill, unity, Ninja, omitting curl tool.
- also test static libcurl.
- add old-cmake support with auto-detection.
- auto-detect Ninja.
- run consumer test apps to see if they work.
- add support for Windows.
- make it more verbose.
- re-add `ExternalProject` cmake consumer test. It's broken.
- tidy up terminology.
Cherry-picked from #16973Closes#17203
- replace `add_compile_options()`, `add_definitions()` with directory
properties. To harmonize this across all scripts. The new commands are
verbose, but describe better how they work. The syntax is also closer
to setting target properties, helps grepping.
- prefer `CMAKE_INSTALL_PREFIX` over `--prefix` (in tests, CI).
- tidy up cmake invocations.
- formatting.
Closes#16238
Add CMake test project consuming curl via these methods:
`FetchContent`, `add_subdirectory()`, `find_package()`.
Also:
- GHA/distcheck: run these tests in CI.
- cmakelint: exclude a warning for calling "wonky-cased" built-in
CMake functions, such as `FetchContent_Declare()`.
Closes#16126
