From 15db98a40022b11fc30f60f60d1ca09576a7898c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mart=C3=AD=20Bol=C3=ADvar?= <marti.bolivar@nordicsemi.no>
Date: Thu, 6 May 2021 16:25:33 -0700
Subject: [PATCH] dtlib: allow dangling aliases with DT(..., force=True)
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As a first step towards being more forgiving on invalid inputs, allow
string-valued aliases properties that do not point to valid nodes when
the user requests permissiveness.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
---
 .../python-devicetree/src/devicetree/dtlib.py  | 11 +++++++++--
 .../dts/python-devicetree/tests/test_dtlib.py  | 18 +++++++++++++++---
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/scripts/dts/python-devicetree/src/devicetree/dtlib.py b/scripts/dts/python-devicetree/src/devicetree/dtlib.py
index c9084f08c1e..9d5f32cf711 100644
--- a/scripts/dts/python-devicetree/src/devicetree/dtlib.py
+++ b/scripts/dts/python-devicetree/src/devicetree/dtlib.py
@@ -1684,8 +1684,15 @@ class DT:
                     _err("/aliases: alias property name '{}' should include "
                          "only characters from [0-9a-z-]".format(prop.name))
 
-                # Property.to_path() already checks that the node exists
-                alias2node[prop.name] = prop.to_path()
+                # Property.to_path() checks that the node exists, has
+                # the right type, etc. Swallow errors for invalid
+                # aliases with self._force.
+                try:
+                    alias2node[prop.name] = prop.to_path()
+                except DTError:
+                    if self._force:
+                        continue
+                    raise
 
         self.alias2node = alias2node
 
diff --git a/scripts/dts/python-devicetree/tests/test_dtlib.py b/scripts/dts/python-devicetree/tests/test_dtlib.py
index c6a07765608..13e5544da6a 100644
--- a/scripts/dts/python-devicetree/tests/test_dtlib.py
+++ b/scripts/dts/python-devicetree/tests/test_dtlib.py
@@ -24,13 +24,15 @@ from devicetree import dtlib
 #   - to run a particular test function or functions, use
 #     '-k test_function_pattern_goes_here'
 
-def parse(dts, include_path=()):
-    '''Parse a DTS string 'dts', using the given include path.'''
+def parse(dts, include_path=(), **kwargs):
+    '''Parse a DTS string 'dts', using the given include path.
+
+    Any kwargs are passed on to DT().'''
 
     fd, path = tempfile.mkstemp(prefix='pytest-', suffix='.dts')
     try:
         os.write(fd, dts.encode('utf-8'))
-        return dtlib.DT(path, include_path)
+        return dtlib.DT(path, include_path, **kwargs)
     finally:
         os.close(fd)
         os.unlink(path)
@@ -2250,3 +2252,13 @@ l1: l2: &foo {
 / {
 };
 """)
+
+def test_dangling_alias():
+    dt = parse('''
+/dts-v1/;
+
+/ {
+	aliases { foo = "/missing"; };
+};
+''', force=True)
+    assert dt.get_node('/aliases').props['foo'].to_string() == '/missing'