2 files changed, 72 insertions, 20 deletions

diff --git a/docs/markdown/Python-module.md b/docs/markdown/Python-module.md
index cad74c9..51721f0 100644
--- a/docs/markdown/Python-module.md
+++ b/docs/markdown/Python-module.md
@@ -142,7 +142,7 @@ This function expects no arguments or keyword arguments.
 #### `get_path()`
 
 ``` meson
-string py_installation.get_path(path_name)
+string py_installation.get_path(path_name, fallback)
 ```
 
 Get a path as defined by the `sysconfig` module.
@@ -153,15 +153,28 @@ For example:
 purelib = py_installation.get_path('purelib')
 ```
 
-This function accepts a single argument, `path_name`, which is expected to
-be a non-empty string.
+This function requires at least one argument, `path_name`,
+which is expected to be a non-empty string.
+
+If `fallback` is specified, it will be returned if no path
+with the given name exists. Otherwise, attempting to read
+a non-existing path will cause a fatal error.
 
 **Returns**: A string
 
+#### `has_path()`
+
+``` meson
+    bool py_installation.has_path(path_name)
+```
+
+**Returns**: true if a path named `path_name` can be retrieved with
+[][`get_path()`], false otherwise.
+
 #### `get_variable()`
 
 ``` meson
-string py_installation.get_variable(variable_name)
+string py_installation.get_variable(variable_name, fallback)
 ```
 
 Get a variable as defined by the `sysconfig` module.
@@ -169,14 +182,27 @@ Get a variable as defined by the `sysconfig` module.
 For example:
 
 ``` meson
-py_bindir = py_installation.get_variable('BINDIR')
+py_bindir = py_installation.get_variable('BINDIR', '')
 ```
 
-This function accepts a single argument, `variable_name`, which is expected to
-be a non-empty string.
+This function requires at least one argument, `variable_name`,
+which is expected to be a non-empty string.
+
+If `fallback` is specified, it will be returned if no variable
+with the given name exists. Otherwise, attempting to read
+a non-existing variable will cause a fatal error.
 
 **Returns**: A string
 
+#### `has_variable()`
+
+``` meson
+    bool py_installation.has_variable(variable_name)
+```
+
+**Returns**: true if a variable named `variable_name` can be retrieved with
+[][`get_variable()`], false otherwise.
+
 ## `python_dependency` object
 
 This [dependency object] subclass will try various methods to obtain the
diff --git a/mesonbuild/modules/python.py b/mesonbuild/modules/python.py
index 16bdfd6..afcae8f 100644
--- a/mesonbuild/modules/python.py
+++ b/mesonbuild/modules/python.py
@@ -313,32 +313,58 @@ class PythonInstallation(ExternalProgramHolder, InterpreterObject):
         return ModuleReturnValue(True, [])
 
     @noKwargs
-    def get_path(self, node, args, kwargs):
+    def has_path(self, node, args, kwargs):
         if len(args) != 1:
-            raise InvalidArguments('get_path takes exactly one positional argument.')
+            raise InvalidArguments('has_path takes exactly one positional argument.')
         path_name = args[0]
         if not isinstance(path_name, str):
-            raise InvalidArguments('get_path argument must be a string.')
+            raise InvalidArguments('has_path argument must be a string.')
+
+        return ModuleReturnValue(path_name in self.paths, [])
 
-        path = self.paths.get(path_name)
+    @noKwargs
+    def get_path(self, node, args, kwargs):
+        if len(args) not in (1, 2):
+            raise InvalidArguments('get_path must have one or two arguments.')
+        path_name = args[0]
+        if not isinstance(path_name, str):
+            raise InvalidArguments('get_path argument must be a string.')
 
-        if path is None:
-            raise InvalidArguments('{} is not a valid path name'.format(path_name))
+        try:
+            path = self.paths[path_name]
+        except KeyError:
+            if len(args) == 2:
+                path = args[1]
+            else:
+                raise InvalidArguments('{} is not a valid path name'.format(path_name))
 
         return ModuleReturnValue(path, [])
 
     @noKwargs
-    def get_variable(self, node, args, kwargs):
+    def has_variable(self, node, args, kwargs):
         if len(args) != 1:
-            raise InvalidArguments('get_variable takes exactly one positional argument.')
+            raise InvalidArguments('has_variable takes exactly one positional argument.')
         var_name = args[0]
         if not isinstance(var_name, str):
-            raise InvalidArguments('get_variable argument must be a string.')
+            raise InvalidArguments('has_variable argument must be a string.')
+
+        return ModuleReturnValue(var_name in self.variables, [])
 
-        var = self.variables.get(var_name)
+    @noKwargs
+    def get_variable(self, node, args, kwargs):
+        if len(args) not in (1, 2):
+            raise InvalidArguments('get_variable must have one or two arguments.')
+        var_name = args[0]
+        if not isinstance(var_name, str):
+            raise InvalidArguments('get_variable argument must be a string.')
 
-        if var is None:
-            raise InvalidArguments('{} is not a valid path name'.format(var_name))
+        try:
+            var = self.variables[var_name]
+        except KeyError:
+            if len(args) == 2:
+                var = args[1]
+            else:
+                raise InvalidArguments('{} is not a valid variable name'.format(var_name))
 
         return ModuleReturnValue(var, [])
 
@@ -351,7 +377,7 @@ class PythonInstallation(ExternalProgramHolder, InterpreterObject):
         if method_name in ['extension_module', 'dependency', 'install_sources']:
             value = fn(self.interpreter, None, args, kwargs)
             return self.interpreter.holderify(value)
-        elif method_name in ['get_variable', 'get_path', 'found', 'language_version', 'get_install_dir']:
+        elif method_name in ['has_variable', 'get_variable', 'has_path', 'get_path', 'found', 'language_version', 'get_install_dir']:
             value = fn(None, args, kwargs)
             return self.interpreter.module_method_callback(value)
         else: