_yaml: Remove 'indices' from 'node_get_provenance'

With nodes being propagated better, we now don't need to extract
provenance beforehand. Therefore removing the ability to provide
indiced when getting provenance.

- Also add 'scalar_at' on 'SequenceNode', in order to fetch a scalar
node at a specific indice

4 files changed, 26 insertions, 26 deletions

diff --git a/src/buildstream/_options/optionarch.py b/src/buildstream/_options/optionarch.py
index e7735eaa2..75be1a8ff 100644
--- a/src/buildstream/_options/optionarch.py
+++ b/src/buildstream/_options/optionarch.py
@@ -55,7 +55,7 @@ class OptionArch(OptionEnum):
                     # Do not terminate the loop early to ensure we validate
                     # all values in the list.
             except PlatformError as e:
-                provenance = _yaml.node_get_provenance(node, key='values', indices=[index])
+                provenance = _yaml.node_get_provenance(node.get_sequence('values').scalar_at(index))
                 prefix = ""
                 if provenance:
                     prefix = "{}: ".format(provenance)
diff --git a/src/buildstream/_options/optionpool.py b/src/buildstream/_options/optionpool.py
index 5155f62f4..f695c0acf 100644
--- a/src/buildstream/_options/optionpool.py
+++ b/src/buildstream/_options/optionpool.py
@@ -262,31 +262,27 @@ class OptionPool():
                             "{}: {}".format(p, assertion.strip()))
 
         if conditions is not None:
-
-            # Collect provenance first, we need to delete the (?) key
-            # before any composition occurs.
-            provenance = [
-                _yaml.node_get_provenance(node, '(?)', indices=[i])
-                for i in range(len(conditions))
-            ]
             del node['(?)']
 
-            for condition, p in zip(conditions, provenance):
+            for condition in conditions:
                 tuples = list(condition.items())
                 if len(tuples) > 1:
+                    provenance = _yaml.node_get_provenance(condition)
                     raise LoadError(LoadErrorReason.INVALID_DATA,
-                                    "{}: Conditional statement has more than one key".format(p))
+                                    "{}: Conditional statement has more than one key".format(provenance))
 
                 expression, value = tuples[0]
                 try:
                     apply_fragment = self._evaluate(expression)
                 except LoadError as e:
                     # Prepend the provenance of the error
-                    raise LoadError(e.reason, "{}: {}".format(p, e)) from e
+                    provenance = _yaml.node_get_provenance(condition)
+                    raise LoadError(e.reason, "{}: {}".format(provenance, e)) from e
 
                 if type(value) is not _yaml.MappingNode:  # pylint: disable=unidiomatic-typecheck
+                    provenance = _yaml.node_get_provenance(condition)
                     raise LoadError(LoadErrorReason.ILLEGAL_COMPOSITE,
-                                    "{}: Only values of type 'dict' can be composed.".format(p))
+                                    "{}: Only values of type 'dict' can be composed.".format(provenance))
 
                 # Apply the yaml fragment if its condition evaluates to true
                 if apply_fragment:
diff --git a/src/buildstream/_yaml.pxd b/src/buildstream/_yaml.pxd
index a3edd83f0..7b5209077 100644
--- a/src/buildstream/_yaml.pxd
+++ b/src/buildstream/_yaml.pxd
@@ -76,6 +76,7 @@ cdef class SequenceNode(Node):
     cpdef void append(self, object value)
     cpdef MappingNode mapping_at(self, int index)
     cpdef Node node_at(self, int index, list allowed_types=*)
+    cpdef ScalarNode scalar_at(self, int index)
     cpdef SequenceNode sequence_at(self, int index)
     cpdef list as_str_list(self)
 
@@ -90,4 +91,4 @@ cdef class ProvenanceInformation:
     cdef public bint is_synthetic
 
 
-cpdef ProvenanceInformation node_get_provenance(Node node, str key=*, list indices=*)
+cpdef ProvenanceInformation node_get_provenance(Node node, str key=*)
diff --git a/src/buildstream/_yaml.pyx b/src/buildstream/_yaml.pyx
index 24efd47d9..2df6a7d1b 100644
--- a/src/buildstream/_yaml.pyx
+++ b/src/buildstream/_yaml.pyx
@@ -620,15 +620,26 @@ cdef class SequenceNode(Node):
                             .format(provenance, path, MappingNode.__name__))
         return value
 
-    cpdef Node node_at(self, int key, list allowed_types = None):
-        cdef value = self.value[key]
+    cpdef Node node_at(self, int index, list allowed_types = None):
+        cdef value = self.value[index]
 
         if allowed_types and type(value) not in allowed_types:
             provenance = node_get_provenance(self)
             raise LoadError(LoadErrorReason.INVALID_DATA,
                             "{}: Value of '{}' is not one of the following: {}.".format(
-                                provenance, key, ", ".join(allowed_types)))
+                                provenance, index, ", ".join(allowed_types)))
+
+        return value
 
+    cpdef ScalarNode scalar_at(self, int index):
+        value = self.value[index]
+
+        if type(value) is not ScalarNode:
+            provenance = node_get_provenance(self)
+            path = ["[{}]".format(p) for p in provenance.toplevel._find(self)] + ["[{}]".format(index)]
+            raise LoadError(LoadErrorReason.INVALID_DATA,
+                            "{}: Value of '{}' is not of the expected type '{}'"
+                            .format(provenance, path, ScalarNode.__name__))
         return value
 
     cpdef SequenceNode sequence_at(self, int index):
@@ -1122,23 +1133,15 @@ cpdef Node load_data(str data, int file_index=_SYNTHETIC_FILE_INDEX, str file_na
 # Args:
 #   node (Node): a dictionary
 #   key (str): key in the dictionary
-#   indices (list of indexes): Index path, in the case of list values
 #
 # Returns: The Provenance of the dict, member or list element
 #
-cpdef ProvenanceInformation node_get_provenance(Node node, str key=None, list indices=None):
+cpdef ProvenanceInformation node_get_provenance(Node node, str key=None):
     if key is None:
         # Retrieving the provenance for this node directly
         return ProvenanceInformation(node)
 
-    if key and not indices:
-        return ProvenanceInformation((<MappingNode> node).value.get(key))
-
-    cdef Node nodeish = <Node> (<MappingNode> node).value.get(key)
-    for idx in indices:
-        nodeish = <Node> (<SequenceNode> nodeish).value[idx]
-
-    return ProvenanceInformation(nodeish)
+    return ProvenanceInformation((<MappingNode> node).value.get(key))
 
 
 # new_synthetic_file()