wrap: Implement special wrap modes for use by packagers

Special wrap modes:
  nofallback: Don't download wraps for dependency() fallbacks
  nodownload: Don't download wraps for all subproject() calls

Subprojects are used for two purposes:
1. To download and build dependencies by using .wrap files if they
   are not provided by the system. This is usually expressed via
   dependency(..., fallback: ...).
2. To download and build 'copylibs' which are meant to be used by
   copying into your project. This is always done with an explicit
   subproject() call.

--wrap-mode=nofallback will never do (1)
--wrap-mode=nodownload will do neither (1) nor (2)

If you are building from a release tarball, you should be able to
safely use 'nodownload' since upstream is expected to ship all
required sources with the tarball.

If you are building from a git repository, you will want to use
'nofallback' so that any 'copylib' wraps will be download as
subprojects.

Note that these options do not affect subprojects that are git
submodules since those are only usable in git repositories, and you
almost always want to download them.

1 files changed, 7 insertions, 2 deletions

diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index f9c1579..6e8cf1a 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -20,7 +20,7 @@ from . import mlog
 from . import build
 from . import optinterpreter
 from . import compilers
-from .wrap import wrap
+from .wrap import wrap, WrapMode
 from . import mesonlib
 from .mesonlib import FileMode, Popen_safe
 from .dependencies import InternalDependency, Dependency
@@ -1499,7 +1499,7 @@ class Interpreter(InterpreterBase):
         if dirname in self.subprojects:
             return self.subprojects[dirname]
         subproject_dir_abs = os.path.join(self.environment.get_source_dir(), self.subproject_dir)
-        r = wrap.Resolver(subproject_dir_abs)
+        r = wrap.Resolver(subproject_dir_abs, self.coredata.wrap_mode)
         try:
             resolved = r.resolve(dirname)
         except RuntimeError as e:
@@ -1911,6 +1911,11 @@ requirements use the version keyword argument instead.''')
         return fbinfo
 
     def dependency_fallback(self, name, kwargs):
+        if self.coredata.wrap_mode in (WrapMode.nofallback, WrapMode.nodownload):
+            mlog.log('Not looking for a fallback subproject for the dependency',
+                     mlog.bold(name), 'because:\nAutomatic wrap-based fallback '
+                     'dependency downloading is disabled.')
+            return None
         dirname, varname = self.get_subproject_infos(kwargs)
         # Try to execute the subproject
         try: