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diff --git a/docs/markdown/snippets/override_dependency.md b/docs/markdown/snippets/override_dependency.md deleted file mode 100644 index ca420bc..0000000 --- a/docs/markdown/snippets/override_dependency.md +++ /dev/null @@ -1,65 +0,0 @@ -## `dependency()` consistency - -The first time a dependency is found, using `dependency('foo', ...)`, the return -value is now cached. Any subsequent call will return the same value as long as -version requested match, otherwise not-found dependency is returned. This means -that if a system dependency is first found, it won't fallback to a subproject -in a subsequent call any more and will rather return not-found instead if the -system version does not match. Similarly, if the first call returns the subproject -fallback dependency, it will also return the subproject dependency in a subsequent -call even if no fallback is provided. - -For example, if the system has `foo` version 1.0: -```meson -# d2 is set to foo_dep and not the system dependency, even without fallback argument. -d1 = dependency('foo', version : '>=2.0', required : false, - fallback : ['foo', 'foo_dep']) -d2 = dependency('foo', version : '>=1.0', required : false) -``` -```meson -# d2 is not-found because the first call returned the system dependency, but its version is too old for 2nd call. -d1 = dependency('foo', version : '>=1.0', required : false) -d2 = dependency('foo', version : '>=2.0', required : false, - fallback : ['foo', 'foo_dep']) -``` - -## Override `dependency()` - -It is now possible to override the result of `dependency()` to point -to any dependency object you want. The overriding is global and applies to -every subproject from there on. - -For example, this subproject provides 2 libraries with version 2.0: - -```meson -project(..., version : '2.0') - -libfoo = library('foo', ...) -foo_dep = declare_dependency(link_with : libfoo) -meson.override_dependency('foo', foo_dep) - -libbar = library('bar', ...) -bar_dep = declare_dependency(link_with : libbar) -meson.override_dependency('bar', bar_dep) -``` - -Assuming the system has `foo` and `bar` 1.0 installed, and master project does this: -```meson -foo_dep = dependency('foo', version : '>=2.0', fallback : ['foo', 'foo_dep']) -bar_dep = dependency('bar') -``` - -This used to mix system 1.0 version and subproject 2.0 dependencies, but thanks -to the override `bar_dep` is now set to the subproject's version instead. - -Another case this can be useful is to force a subproject to use a specific dependency. -If the subproject does `dependency('foo')` but the main project wants to provide -its own implementation of `foo`, it can for example call -`meson.override_dependency('foo', declare_dependency(...))` before configuring the -subproject. - -## Simplified `dependency()` fallback - -In the case a subproject `foo` calls `meson.override_dependency('foo-2.0', foo_dep)`, -the parent project can omit the dependency variable name in fallback keyword -argument: `dependency('foo-2.0', fallback : 'foo')`. |