feat: teach Part to skip exceptions

kalekundert · Oct 3, 2022 · 4eca860 · 4eca860
1 parent 4a99f25
commit 4eca860
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Showing 2 changed files with 104 additions and 3 deletions.
diff --git a/byoc/getters.py b/byoc/getters.py
@@ -145,7 +145,7 @@ def bind(self, obj, param):
 
 class Part(Getter):
 
-    def __init__(self, whole, index=noop, **kwargs):
+    def __init__(self, whole, index=noop, skip=(), **kwargs):
         super().__init__(**kwargs)
 
         # Strictly speaking, the user should provide the same "whole" getter 
@@ -176,6 +176,7 @@ def __init__(self, whole, index=noop, **kwargs):
 
         self.whole = whole
         self.index = index
+        self.skip = skip
 
     def __reprargs__(self):
         if self.index is noop:
@@ -380,8 +381,21 @@ def _iter_values(self, log):
                         f"reusing value from parameter {name!r}: {values!r}"
                 )
 
-            value = lookup(values, self.parent.index)
-            yield value, meta, dynamic
+            try:
+                value = lookup(values, self.parent.index)
+            except self.parent.skip as err:
+                log += lambda err=err: (
+                        f"called: {self.parent.index!r}\nraised {err.__class__.__name__}: {err}"
+                        if callable(self.parent.index) else
+                        f"did not find {self.parent.index!r} in {values!r}\nraised {err.__class__.__name__}: {err}"
+                )
+            else:
+                log += lambda: (
+                        f"called: {self.parent.index!r}\nreturned: {value!r}"
+                        if callable(self.parent.index) else
+                        f"found {self.parent.index!r}: {value!r}"
+                )
+                yield value, meta, dynamic
 
     def cleanup(self, log):
         if not self.update_peers:

diff --git a/tests/test_getters.nt b/tests/test_getters.nt
@@ -1049,9 +1049,50 @@ test_getter_iter_values:
       log:
         - queried DummyConfig\(\):
         - found 'x': 'a,b'
+        - found 0: 'a'
 
         - getting 'x2' parameter for <DummyObj object at .*>
         - reusing value from parameter 'x1': \['a', 'b'\]
+        - found 1: 'b'
+  -
+    id: part-skip
+    obj:
+      > class DummyConfig(Config):
+      >     def load(self):
+      >         yield DictLayer({'x': 'a,b'})
+      >
+      > key = Key(DummyConfig, 'x', cast=lambda x: x.split(','))
+      > parts = [
+      >       Part(key, index=0),
+      >       Part(key, index=2, skip=IndexError),
+      > ]
+      >
+      > class DummyObj:
+      >     __config__ = [DummyConfig]
+      >     x1 = byoc.param(parts[0])
+      >     x2 = byoc.param(parts[1])
+    param: x1
+    getter:
+      > parts[0]
+    expected:
+      values: ['a']
+      meta:
+        -
+          type: LayerMeta
+          layer.values: {'x': 'a,b'}
+      dynamic:
+        - False
+      log:
+        - queried DummyConfig\(\):
+        - found 'x': 'a,b'
+        - found 0: 'a'
+
+        - getting 'x2' parameter for <DummyObj object at .*>
+        - reusing value from parameter 'x1': \['a', 'b'\]
+        -
+          > did not find 2 in \['a', 'b'\]
+          > raised IndexError: list index out of range
+        - did you mean to provide a default\?
 
 test_getter_kwargs_err:
   -
@@ -1390,5 +1431,51 @@ test_part:
       x2: 'b'
     n_calls:
       f: 1
+  -
+    id: skip-first
+    funcs:
+      f: lambda x: x.split(',')
+    obj:
+      > class DummyConfig(byoc.Config):
+      >     def load(self):
+      >         yield byoc.DictLayer({'x': 'a,b'})
+      > 
+      > class DummyObj:
+      >     __config__ = [DummyConfig]
+      >     x1 = byoc.param(
+      >             Part(Key(DummyConfig, 'x', cast=f), index=2, skip=IndexError),
+      >             default=None,
+      >     )
+      >     x2 = byoc.param(
+      >             Part(x1, index=1),
+      >     )
+    expected:
+      x1: None
+      x2: 'b'
+    n_calls:
+      f: 1
+  -
+    id: skip-second
+    funcs:
+      f: lambda x: x.split(',')
+    obj:
+      > class DummyConfig(byoc.Config):
+      >     def load(self):
+      >         yield byoc.DictLayer({'x': 'a,b'})
+      > 
+      > class DummyObj:
+      >     __config__ = [DummyConfig]
+      >     x1 = byoc.param(
+      >             Part(Key(DummyConfig, 'x', cast=f), index=0),
+      >     )
+      >     x2 = byoc.param(
+      >             Part(x1, index=2, skip=IndexError),
+      >             default=None,
+      >     )
+    expected:
+      x1: 'a'
+      x2: None
+    n_calls:
+      f: 1