Store pkg-config path on the instance too

We were storing the pkg-config path on the class as a static variable --
PkgConfigDependency.pkgbin. When we regenerate via Ninja, the found-deps
are all cached in a pickled coredata, so if you have a statement that
does dep.get_pkgconfig_variable(), it will raise the following exception
because the static class variables are per-meson-invocation.

To fix this, we store the pkg-config binary as both a class variable and
an instance variable.

Traceback (most recent call last):
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/mesonmain.py", line 289, in run
    app.generate()
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/mesonmain.py", line 177, in generate
    intr.run()
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreter.py", line 2215, in run
    super().run()
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 124, in run
    self.evaluate_codeblock(self.ast, start=1)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 145, in evaluate_codeblock
    raise e
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 139, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 150, in evaluate_statement
    return self.function_call(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 371, in function_call
    return self.funcs[func_name](node, self.flatten(posargs), kwargs)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 47, in wrapped
    return f(self, node, args, kwargs)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreter.py", line 2035, in func_subdir
    self.evaluate_codeblock(codeblock)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 145, in evaluate_codeblock
    raise e
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 139, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 160, in evaluate_statement
    return self.evaluate_if(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 213, in evaluate_if
    self.evaluate_codeblock(i.block)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 145, in evaluate_codeblock
    raise e
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 139, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 160, in evaluate_statement
    return self.evaluate_if(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 213, in evaluate_if
    self.evaluate_codeblock(i.block)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 145, in evaluate_codeblock
    raise e
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 139, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 182, in evaluate_statement
    return self.evaluate_plusassign(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 333, in evaluate_plusassign
    addition = self.evaluate_statement(node.value)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 166, in evaluate_statement
    return self.evaluate_arraystatement(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 193, in evaluate_arraystatement
    (arguments, kwargs) = self.reduce_arguments(cur.args)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 515, in reduce_arguments
    reduced_pos = [self.evaluate_statement(arg) for arg in args.arguments]
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 515, in <listcomp>
    reduced_pos = [self.evaluate_statement(arg) for arg in args.arguments]
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 154, in evaluate_statement
    return self.method_call(cur)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreterbase.py", line 399, in method_call
    return obj.method_call(method_name, self.flatten(args), kwargs)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/interpreter.py", line 982, in method_call
    value = fn(state, args, kwargs)
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/modules/gnome.py", line 499, in generate_gir
    girdir = dep.get_pkgconfig_variable("girdir")
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/dependencies.py", line 219, in get_pkgconfig_variable
    ret, out = self._call_pkgbin(['--variable=' + variable_name, self.name])
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/dependencies.py", line 184, in _call_pkgbin
    p, out = Popen_safe([PkgConfigDependency.pkgbin] + args, env=os.environ)[0:2]
  File "/home/nirbheek/projects/repositories/github/meson.git/mesonbuild/mesonlib.py", line 392, in Popen_safe
    stderr=stderr, **kwargs)
  File "/usr/lib64/python3.5/subprocess.py", line 947, in __init__
    restore_signals, start_new_session)
  File "/usr/lib64/python3.5/subprocess.py", line 1474, in _execute_child
    executable = os.fsencode(executable)
  File "/usr/lib64/python3.5/os.py", line 862, in fsencode
    raise TypeError("expect bytes or str, not %s" % type(filename).__name__)
TypeError: expect bytes or str, not NoneType
FAILED: build.ninja
'/usr/bin/python3' '/home/nirbheek/projects/repositories/github/meson.git/meson.py' --internal regenerate '/home/nirbheek/projects/repositories/gst/gstreamer' '/home/nirbheek/projects/repositories/gst/gstreamer/build' --backend ninja
ninja: error: rebuilding 'build.ninja': subcommand failed

mesonbuild/dependencies.py

@@ -89,7 +89,9 @@ class InternalDependency(Dependency):
         return self.version
 
 class PkgConfigDependency(Dependency):
-    pkgbin = None
+    # The class's copy of the pkg-config path. Avoids having to search for it
+    # multiple times in the same Meson invocation.
+    class_pkgbin = None
 
     def __init__(self, name, environment, kwargs):
         Dependency.__init__(self, 'pkgconfig')
@@ -99,6 +101,9 @@ class PkgConfigDependency(Dependency):
         self.silent = kwargs.get('silent', False)
         if not isinstance(self.static, bool):
             raise DependencyException('Static keyword must be boolean')
+        # Store a copy of the pkg-config path on the object itself so it is
+        # stored in the pickled coredata and recovered.
+        self.pkgbin = None
         self.cargs = []
         self.libs = []
         if 'native' in kwargs and environment.is_cross_build():
@@ -114,11 +119,15 @@ class PkgConfigDependency(Dependency):
                 if self.required:
                     raise DependencyException('Pkg-config binary missing from cross file')
             else:
-                PkgConfigDependency.pkgbin = environment.cross_info.config['binaries']['pkgconfig']
+                self.pkgbin = environment.cross_info.config['binaries']['pkgconfig']
+                PkgConfigDependency.class_pkgbin = self.pkgbin
         # Only search for the native pkg-config the first time and
         # store the result in the class definition
-        elif PkgConfigDependency.pkgbin is None:
-            PkgConfigDependency.pkgbin = self.check_pkgconfig()
+        elif PkgConfigDependency.class_pkgbin is None:
+            self.pkgbin = self.check_pkgconfig()
+            PkgConfigDependency.class_pkgbin = self.pkgbin
+        else:
+            self.pkgbin = PkgConfigDependency.class_pkgbin
 
         self.is_found = False
         if not self.pkgbin: