compilers: New class CompilerArgs derived from list()

The purpose of this class is to make it possible to sanely generate
compiler command-lines by ensuring that new arguments appended or added
to a list of arguments properly override previous arguments.
For instance:

>>> a = CompilerArgs(['-Lfoo', '-DBAR'])
>>> a += ['-Lgah', '-DTAZ']
>>> print(a)
['-Lgah', '-Lfoo', '-DBAR', '-DTAZ']

Arguments will be de-duped if it is safe to do so. Currently, this is
only done for -I and -L arguments (previous occurances are removed when
a new one is added) and arguments that once added cannot be overriden
such as -pipe are removed completely.

1 files changed, 58 insertions, 1 deletions

diff --git a/run_unittests.py b/run_unittests.py
index 5eba222..a90e46b 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -19,6 +19,7 @@ import subprocess
 import re, json
 import tempfile
 from glob import glob
+import mesonbuild.compilers
 import mesonbuild.environment
 import mesonbuild.mesonlib
 from mesonbuild.environment import detect_ninja, Environment
@@ -95,6 +96,62 @@ class InternalTests(unittest.TestCase):
                          stat.S_IRWXU | stat.S_ISUID |
                          stat.S_IRGRP | stat.S_IXGRP)
 
+    def test_compiler_args_class(self):
+        cargsfunc = mesonbuild.compilers.CompilerArgs
+        c = mesonbuild.environment.CCompiler([], 'fake', False)
+        # Test that bad initialization fails
+        self.assertRaises(TypeError, cargsfunc, [])
+        self.assertRaises(TypeError, cargsfunc, [], [])
+        self.assertRaises(TypeError, cargsfunc, c, [], [])
+        # Test that empty initialization works
+        a = cargsfunc(c)
+        self.assertEqual(a, [])
+        # Test that list initialization works
+        a = cargsfunc(['-I.', '-I..'], c)
+        self.assertEqual(a, ['-I.', '-I..'])
+        # Test that there is no de-dup on initialization
+        self.assertEqual(cargsfunc(['-I.', '-I.'], c), ['-I.', '-I.'])
+
+        ## Test that appending works
+        a.append('-I..')
+        self.assertEqual(a, ['-I..', '-I.'])
+        a.append('-O3')
+        self.assertEqual(a, ['-I..', '-I.', '-O3'])
+
+        ## Test that in-place addition works
+        a += ['-O2', '-O2']
+        self.assertEqual(a, ['-I..', '-I.', '-O3', '-O2', '-O2'])
+        # Test that removal works
+        a.remove('-O2')
+        self.assertEqual(a, ['-I..', '-I.', '-O3', '-O2'])
+        # Test that de-dup happens on addition
+        a += ['-Ifoo', '-Ifoo']
+        self.assertEqual(a, ['-Ifoo', '-I..', '-I.', '-O3', '-O2'])
+
+        # .extend() is just +=, so we don't test it
+
+        ## Test that addition works
+        # Test that adding a list with just one old arg works and yields the same array
+        a = a + ['-Ifoo']
+        self.assertEqual(a, ['-Ifoo', '-I..', '-I.', '-O3', '-O2'])
+        # Test that adding a list with one arg new and one old works
+        a = a + ['-Ifoo', '-Ibaz']
+        self.assertEqual(a, ['-Ifoo', '-Ibaz', '-I..', '-I.', '-O3', '-O2'])
+        # Test that adding args that must be prepended and appended works
+        a = a + ['-Ibar', '-Wall']
+        self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-O3', '-O2', '-Wall'])
+
+        ## Test that reflected addition works
+        # Test that adding to a list with just one old arg works and DOES NOT yield the same array
+        a = ['-Ifoo'] + a
+        self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-O3', '-O2', '-Wall'])
+        # Test that adding to a list with just one new arg that is not pre-pended works
+        a = ['-Werror'] + a
+        self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-Werror', '-O3', '-O2', '-Wall'])
+        # Test that adding to a list with two new args preserves the order
+        a = ['-Ldir', '-Lbah'] + a
+        self.assertEqual(a, ['-Ibar', '-Ifoo', '-Ibaz', '-I..', '-I.', '-Ldir', '-Lbah', '-Werror', '-O3', '-O2', '-Wall'])
+
 
 class LinuxlikeTests(unittest.TestCase):
     def setUp(self):
@@ -416,7 +473,7 @@ class LinuxlikeTests(unittest.TestCase):
                 cmd = cmd[1:]
             # Verify that -I flags from the `args` kwarg are first
             # This is set in the '43 has function' test case
-            self.assertEqual(cmd[2], '-I/tmp')
+            self.assertEqual(cmd[1], '-I/tmp')
             # Verify that -O3 set via the environment is overriden by -O0
             Oargs = [arg for arg in cmd if arg.startswith('-O')]
             self.assertEqual(Oargs, [Oflag, '-O0'])