ExternalProgram and CustomTarget have some use cases for producing
subclassed interpreter holders with more specific types and methods. In
order for those subclasses to properly refer to their held_object, we
need a shared base class that is still generic, though bound.
For the derived held objects, inherit from the base class and specify
the final types as the module-specific type.
This detects cases where module A imports a function from B, and C
imports that same function from A instead of B. It's not part of the API
contract of A, and causes innocent refactoring to break things.
This adds two new methods, that are conceptually related in the same way
that `enable_auto_if` and `disable_auto_if` are. They are different
however, in that they will always replace an `auto` value with an
`enabled` or `disabled` value, or error if the feature is in the
opposite state (calling `feature(disabled).enable_if(true)`, for
example). This matters when the feature will be passed to
dependency(required : …)`, which has different behavior when passed an
enabled feature than an auto one.
The `disable_if` method will be controversial, I'm sure, since it
can be expressed via `feature.require()` (`feature.require(not
condition) == feature.disable_if(condition)`). I have two defences of
this:
1) `feature.require` is difficult to reason about, I would expect
require to be equivalent to `feature.enable_if(condition)`, not to
`feature.disable_if(not condition)`.
2) mixing `enable_if` and `disable_if` in the same call chain is much
clearer than mixing `require` and `enable_if`:
```meson
get_option('feat') \
.enable_if(foo) \
.disable_if(bar) \
.enable_if(opt)
```
vs
```meson
get_option('feat') \
.enable_if(foo) \
.require(not bar) \
.enable_if(opt)
```
In the first chain it's immediately obvious what is happening, in the
second, not so much, especially if you're not familiar with what
`require` means.
It's always been strange to me we don't have an opposite method of the
`disable_auto_if` method, but I've been pressed to find a case where we
_need_ one, because `disable_auto_if` can't be logically contorted to
work. I finally found the case where they're not equivalent: when you
don't want to convert to a boolean:
```meson
f = get_option('feat').disable_auto_if(not foo)
g = get_option('feat').enable_auto_if(foo)
dep1 = dependency('foo', required : f)
dep2 = dependency('foo', required : g)
```
This finds uses of deny-listed functions, which defaults to map and
filter. These functions should be replaced by comprehensions in
idiomatic python because:
1. comprehensions are more heavily optimized and are often faster
2. They avoid the need for lambdas in some cases, which make them
faster
3. you can do the equivalent in one statement rather than two, which
is faster
4. They're easier to read
5. if you need a concrete instance (ie, a list) then you don't have
to convert the iterator to a list afterwards
This fixes bogus messages "skipped: feature foo disabled" when
auto_features=disabled. It was reporting the name of the latest
get_option() call instead of the name of the current feature option.
This is especially visible in GStreamer summary where it should show a
different option name for every subproject but instead shows "tools"
everywhere:
```
Subprojects
gst-devtools : NO Feature 'tools' disabled
gst-editing-services : NO Feature 'tools' disabled
...
```
This allows tracking which subproject it came from at the time of
definition, rather than the time of use. As a result, it is no longer
possible for one subproject which knows that another subproject installs
some data files, to expose those data files via its own
declare_dependency.
There are somewhat common, reasonable and legitimate use cases for a
dependency to provide data files installed to /usr which are used as
command inputs. When getting a dependency from a subproject, however,
the attempt to directly construct an input file from a subproject
results in a sandbox violation. This means not all dependencies can be
wrapped as a subproject.
One example is wayland-protocols XML files which get scanned and used to
produce C source files.
Teach Meson to recognize when a string path is the result of fetching a
dep.get_variable(), and special case this to be exempt from subproject
violations.
A requirement of this is that the file must be installed by
install_data() or install_subdir() because otherwise it is not actually
representative of what a pkg-config dependency would provide.
dep.get_variable() only supports string values for pkg-config and
config-tool, because those interfaces use text communication, and
internal variables (from declare_dependency) operate the same way.
CMake had an oddity, where get_variable doesn't document that it allows
list values but apparently it miiiiiight work? Actually getting that
kind of result would be dangerously inconsistent though. Also, CMake
does not support lists so it's a lie. Strings that are *treated* as
lists with `;` splitting don't count...
We could do two things here:
- raise an error
- treat it as a string and return a string
It's not clear what the use case of get_variable() on a maybe-list is,
and should probably be a hard error. But that's controversial, so
instead we just return the original `;`-delimited string. It is probably
the wrong thing, but users are welcome to cope with that somehow on
their own.
These are only used for type checking, so don't bother importing them at
runtime.
Generally add future annotations at the same time, to make sure that
existing uses of these imports don't need to be quoted.
Using future annotations, type annotations become strings at runtime and
don't impact performance. This is not possible to do with T.cast though,
because it is a function argument instead of an annotation.
Quote the type argument everywhere in order to have the same effect as
future annotations. This also allows linters to better detect in some
cases that a given import is typing-only.
It is often useful to check the found version of a program without
checking whether you can successfully find
`find_program('foo', required: false, version: '>=XXX')`
The point of a .use() function is because we don't always have the
information we need to use a feature check, so we allow creating the
feature and then storing it for later use. When implementing location
checks, although it is optional, actually using it violated that design.
Move the location out of the init method for FeatureCheck itself. It
remains compatible with all cases of .single_use(), but fix the rest up.
Use a derived type when passing `subproject` around, so that mypy knows
it's actually a SubProject, not a str. This means that passing anything
other than a handle to the interpreter state's subproject attribute
becomes a type violation, specifically when the order of the *four*
different str arguments is typoed.
This is currently allowed, and is used in at least a few projects. It
was not intended to work or documented, but it does and since it is in
use a full deprecation period must be used. A warning has also been
added for values < 0, which have surprising behavior.
This removes the ability to use ConfigurationData as a dict, but
restricting the inputs to `str | int | bool`. This may be a little too
soon for this, and we may want to wait on that part, it's only bee 8
months since we started warning about this.
This is a layering violation, we're relying on the way the interpreter
handles keyword arguments. Instead, pass them as free variables,
destructuring in the interpreter
Xavier Claessens
Eli Schwartz
Jussi Pakkanen
Dylan Baker
David Robillard
Paolo Bonzini
Daniel Mensinger