stabilize sets that are converted to lists

The order of elements in sets cannot be relied upon, because the hash
values are randomized by Python.  Whenever sets are converted to lists
we need to keep their order stable, or random changes in the command line
cause ninja to rebuild a lot of files unnecessarily.  To stabilize them,
use either sort or OrderedSet.  Sorting is not always applicable, but it
can be faster because it's done in C and it can produce slightly nicer
output.

2 files changed, 3 insertions, 3 deletions

diff --git a/mesonbuild/depfile.py b/mesonbuild/depfile.py
index 7a896cd..62cbe81 100644
--- a/mesonbuild/depfile.py
+++ b/mesonbuild/depfile.py
@@ -82,4 +82,4 @@ class DepFile:
         deps.update(target.deps)
         for dep in target.deps:
             deps.update(self.get_all_dependencies(dep, visited))
-        return deps
+        return sorted(deps)
diff --git a/mesonbuild/modules/sourceset.py b/mesonbuild/modules/sourceset.py
index e23e12e..e49a548 100644
--- a/mesonbuild/modules/sourceset.py
+++ b/mesonbuild/modules/sourceset.py
@@ -14,7 +14,7 @@
 
 from collections import namedtuple
 from .. import mesonlib
-from ..mesonlib import listify
+from ..mesonlib import listify, OrderedSet
 from . import ExtensionModule
 from ..interpreterbase import (
     noPosargs, noKwargs, permittedKwargs,
@@ -111,7 +111,7 @@ class SourceSetHolder(MutableInterpreterObject, ObjectHolder):
 
     def collect(self, enabled_fn, all_sources, into=None):
         if not into:
-            into = SourceFiles(set(), set())
+            into = SourceFiles(OrderedSet(), OrderedSet())
         for entry in self.held_object:
             if all(x.found() for x in entry.dependencies) and \
                all(enabled_fn(key) for key in entry.keys):