Bug 1498450 - Avoid the footgun from @depends-function comparison r=froydnj

While we do have some uses of @depends-function comparison in some
templaces, related to host/target, we ought to be using `is` comparisons
rather than `==` anyways, so we switch those, and prevent other kinds of
comparisons being used at all.

This unveils the one noted in
https://phabricator.services.mozilla.com/D7713?id=21357#inline-30414
(and surprisingly only that one), that we remove entirely since it was
doing nothing in practice. Bug 1492305 will have to add it back in a
proper form.

Differential Revision: https://phabricator.services.mozilla.com/D8501

--HG--
extra : moz-landing-system : lando

build/moz.configure/compile-checks.configure

@@ -112,8 +112,8 @@ def check_and_add_flags(flag, flags_collection, test_flags,
         flags = [flag]
 
     for c in compilers:
-        assert c in (c_compiler, cxx_compiler,
-                     host_c_compiler, host_cxx_compiler)
+        assert c in {c_compiler, cxx_compiler,
+                     host_c_compiler, host_cxx_compiler}
         lang, list_of_flags = {
             c_compiler: ('C', flags_collection.cflags),
             cxx_compiler: ('C++', flags_collection.cxxflags),

build/moz.configure/rust.configure

@@ -152,7 +152,7 @@ def rust_triple_alias(host_or_target):
     `host_or_target` is either `host` or `target` (the @depends functions
     from init.configure).
     """
-    assert host_or_target in (host, target)
+    assert host_or_target in {host, target}
 
     @depends(rustc, host_or_target, c_compiler, rust_supported_targets,
              when=rust_compiler)

build/moz.configure/toolchain.configure

@@ -693,7 +693,7 @@ def default_c_compilers(host_or_target, other_c_compiler=None):
     from init.configure.
     `other_c_compiler` is the `target` C compiler when `host_or_target` is `host`.
     '''
-    assert host_or_target in (host, target)
+    assert host_or_target in {host, target}
 
     other_c_compiler = () if other_c_compiler is None else (other_c_compiler,)
 
@@ -838,11 +838,11 @@ def compiler(language, host_or_target, c_compiler=None, other_compiler=None,
     `other_c_compiler` is the result of the `compiler` template for the
     language 'C' for `target`.
     '''
-    assert host_or_target in (host, target)
+    assert host_or_target in {host, target}
     assert language in ('C', 'C++')
     assert language == 'C' or c_compiler is not None
-    assert host_or_target == target or other_compiler is not None
-    assert language == 'C' or host_or_target == target or \
+    assert host_or_target is target or other_compiler is not None
+    assert language == 'C' or host_or_target is target or \
         other_c_compiler is not None
 
     host_or_target_str = {
@@ -1050,7 +1050,7 @@ def compiler(language, host_or_target, c_compiler=None, other_compiler=None,
     # need to check this works for preprocessing, because we already relied
     # on $CC -E/$CXX -E doing preprocessing work to validate the compiler
     # in the first place.
-    if host_or_target == target:
+    if host_or_target is target:
         pp_var = {
             'C': 'CPP',
             'C++': 'CXXCPP',
@@ -1079,7 +1079,7 @@ def compiler(language, host_or_target, c_compiler=None, other_compiler=None,
                 log.warning('The value of %s is not used by this build system.'
                             % linker_var)
 
-        if host_or_target == target:
+        if host_or_target is target:
             @depends(valid_compiler)
             def is_msvc(compiler):
                 return compiler.type == 'msvc'

moz.configure

@@ -169,7 +169,7 @@ def so_version(value):
 
 @template
 def library_name_info_template(host_or_target):
-    assert host_or_target in (host, target)
+    assert host_or_target in {host, target}
     compiler = {
         host: host_c_compiler,
         target: c_compiler,

python/mozbuild/mozbuild/configure/__init__.py

@@ -66,6 +66,31 @@ class SandboxDependsFunction(object):
                                  'with another @depends function.')
         return self._and(other).sandboxed
 
+    def __cmp__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __eq__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __ne__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __lt__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __le__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __gt__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __ge__(self, other):
+        raise ConfigureError('Cannot compare @depends functions.')
+
+    def __nonzero__(self):
+        raise ConfigureError('Cannot use @depends functions in '
+                             'e.g. conditionals.')
+
     def __getattr__(self, key):
         return self._getattr(key).sandboxed
 

toolkit/moz.configure

@@ -734,18 +734,6 @@ set_config('MOZ_IPDL_TESTS',
 
 include('nss.configure')
 
-# LibSecret
-# ==============================================================
-# To access the OS key store on Linux systems we use libsecret.
-# https://developer.gnome.org/libsecret/
-
-if target.os == 'Linux':
-    libsecret = pkg_check_modules('MOZ_LIB_SECRET', 'libsecret-1',
-                                  allow_missing=True)
-
-    set_config('MOZ_LIB_SECRET', depends_if(libsecret)(lambda _: True))
-    set_define('MOZ_LIB_SECRET', depends_if(libsecret)(lambda _: True))
-
 # Graphics
 # ==============================================================
 option('--disable-skia', help='Disable use of Skia')