environment: Support taking values from dict

Related to #5955.

6 files changed, 78 insertions, 18 deletions

diff --git a/docs/markdown/External-commands.md b/docs/markdown/External-commands.md
index 4c8c8e4..cafd280 100644
--- a/docs/markdown/External-commands.md
+++ b/docs/markdown/External-commands.md
@@ -16,7 +16,14 @@ output = r.stdout().strip()
 errortxt = r.stderr().strip()
 ```
 
-Additionally, since 0.50.0, you can pass the command [`environment`](Reference-manual.html#environment-object) object:
+Since 0.52.0, you can pass the command environment as a dictionary:
+
+```meson
+run_command('command', 'arg1', 'arg2', env: {'FOO': 'bar'})
+```
+
+Since 0.50.0, you can also pass the command
+[`environment`](Reference-manual.html#environment-object) object:
 
 ```meson
 env = environment()
diff --git a/docs/markdown/Reference-manual.md b/docs/markdown/Reference-manual.md
index f296e43..6009d30 100644
--- a/docs/markdown/Reference-manual.md
+++ b/docs/markdown/Reference-manual.md
@@ -104,7 +104,10 @@ Add a custom test setup that can be used to run the tests with a
 custom setup, for example under Valgrind. The keyword arguments are
 the following:
 
-- `env` an [environment object](#environment-object) to use a custom environment
+- `env` environment variables to set, such as `['NAME1=value1',
+  'NAME2=value2']`, or an [`environment()`
+  object](#environment-object) which allows more sophisticated
+  environment juggling. *Since 0.52.0* a dictionary is also accepted.
 - `exe_wrapper` a list containing the wrapper command or script followed by the arguments to it
 - `gdb` if `true`, the tests are also run under `gdb`
 - `timeout_multiplier` a number to multiply the test timeout with
@@ -491,12 +494,16 @@ Print the argument string and halts the build process.
 ### environment()
 
 ``` meson
-    environment_object environment()
+    environment_object environment(...)
 ```
 
 Returns an empty [environment variable
 object](#environment-object). Added in 0.35.0.
 
+Since *0.52.0* takes an optional dictionary as first argument. If
+provided, each key/value pair is added into the `environment_object`
+as if `set()` method was called for each of them.
+
 ### executable()
 
 ``` meson
@@ -1256,7 +1263,10 @@ This function supports the following keyword arguments:
    be checked, and the configuration will fail if it is non-zero. The default is
    `false`.
    Since 0.47.0
- - `env` an [environment object](#environment-object) to use a custom environment
+ - `env` environment variables to set, such as `['NAME1=value1',
+   'NAME2=value2']`, or an [`environment()`
+   object](#environment-object) which allows more sophisticated
+   environment juggling. *Since 0.52.0* a dictionary is also accepted.
    Since 0.50.0
 
 See also [External commands](External-commands.md).
@@ -1489,7 +1499,7 @@ Keyword arguments are the following:
 - `env` environment variables to set, such as `['NAME1=value1',
   'NAME2=value2']`, or an [`environment()`
   object](#environment-object) which allows more sophisticated
-  environment juggling
+  environment juggling. *Since 0.52.0* a dictionary is also accepted.
 
 - `is_parallel` when false, specifies that no other test must be
   running at the same time as this test
diff --git a/docs/markdown/snippets/env_dict.md b/docs/markdown/snippets/env_dict.md
new file mode 100644
index 0000000..5949806
--- /dev/null
+++ b/docs/markdown/snippets/env_dict.md
@@ -0,0 +1,8 @@
+## Support taking environment values from a dictionary
+
+`environment()` now accepts a dictionary as first argument.  If
+provided, each key/value pair is added into the `environment_object`
+as if `set()` method was called for each of them.
+
+On the various functions that take an `env:` keyword argument, you may
+now give a dictionary.
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 96c56ca..2a77eaa 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -222,13 +222,28 @@ class ConfigureFileHolder(InterpreterObject, ObjectHolder):
 
 
 class EnvironmentVariablesHolder(MutableInterpreterObject, ObjectHolder):
-    def __init__(self):
+    def __init__(self, initial_values=None):
         MutableInterpreterObject.__init__(self)
         ObjectHolder.__init__(self, build.EnvironmentVariables())
         self.methods.update({'set': self.set_method,
                              'append': self.append_method,
                              'prepend': self.prepend_method,
                              })
+        if isinstance(initial_values, dict):
+            for k, v in initial_values.items():
+                self.set_method([k, v], {})
+        elif isinstance(initial_values, list):
+            for e in initial_values:
+                if '=' not in e:
+                    raise InterpreterException('Env var definition must be of type key=val.')
+                (k, val) = e.split('=', 1)
+                k = k.strip()
+                val = val.strip()
+                if ' ' in k:
+                    raise InterpreterException('Env var key must not have spaces in it.')
+                self.set_method([k, val], {})
+        elif initial_values:
+            raise AssertionError('Unsupported EnvironmentVariablesHolder initial_values')
 
     def __repr__(self):
         repr_str = "<{0}: {1}>"
@@ -3360,19 +3375,14 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
         envlist = kwargs.get('env', EnvironmentVariablesHolder())
         if isinstance(envlist, EnvironmentVariablesHolder):
             env = envlist.held_object
+        elif isinstance(envlist, dict):
+            FeatureNew('environment dictionary', '0.52.0').use(self.subproject)
+            env = EnvironmentVariablesHolder(envlist)
+            env = env.held_object
         else:
             envlist = listify(envlist)
             # Convert from array to environment object
-            env = EnvironmentVariablesHolder()
-            for e in envlist:
-                if '=' not in e:
-                    raise InterpreterException('Env var definition must be of type key=val.')
-                (k, val) = e.split('=', 1)
-                k = k.strip()
-                val = val.strip()
-                if ' ' in k:
-                    raise InterpreterException('Env var key must not have spaces in it.')
-                env.set_method([k, val], {})
+            env = EnvironmentVariablesHolder(envlist)
             env = env.held_object
         return env
 
@@ -3936,9 +3946,18 @@ different subdirectory.
             argsdict[lang] = argsdict.get(lang, []) + args
 
     @noKwargs
-    @noPosargs
+    @noArgsFlattening
     def func_environment(self, node, args, kwargs):
-        return EnvironmentVariablesHolder()
+        if len(args) > 1:
+            raise InterpreterException('environment takes only one optional positional arguments')
+        elif len(args) == 1:
+            FeatureNew('environment positional arguments', '0.52.0').use(self.subproject)
+            initial_values = args[0]
+            if not isinstance(initial_values, dict) and not isinstance(initial_values, list):
+                raise InterpreterException('environment first argument must be a dictionary or a list')
+        else:
+            initial_values = {}
+        return EnvironmentVariablesHolder(initial_values)
 
     @stringArgs
     @noKwargs
diff --git a/test cases/unit/69 test env value/meson.build b/test cases/unit/69 test env value/meson.build
new file mode 100644
index 0000000..aa3dbc3
--- /dev/null
+++ b/test cases/unit/69 test env value/meson.build
@@ -0,0 +1,10 @@
+project('test env value')
+
+testpy = find_program('test.py')
+
+val = ['1', '2', '3']
+foreach v: val
+    test('check env', testpy, args: [v], env: {'TEST_VAR': v})
+endforeach
+test('check env', testpy, args: ['4'], env: environment({'TEST_VAR': '4'}))
+test('check env', testpy, args: ['5'], env: environment(['TEST_VAR=5']))
diff --git a/test cases/unit/69 test env value/test.py b/test cases/unit/69 test env value/test.py
new file mode 100755
index 0000000..0cc7645
--- /dev/null
+++ b/test cases/unit/69 test env value/test.py
@@ -0,0 +1,6 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+assert(os.environ['TEST_VAR'] == sys.argv[1])