flow analysis working for elif statements (even in combination with else)

jedi/evaluate/flow_analysis.py

@@ -35,26 +35,33 @@ UNSURE = Status(None, 'unsure')
 def break_check(evaluator, base_scope, element_scope):
     reachable = REACHABLE
     if isinstance(element_scope, Flow):
+        if element_scope.command == 'else':
             check_scope = element_scope
-        invert = False
-        if check_scope.command == 'else':
+            while check_scope.previous is not None:
                 check_scope = check_scope.previous
-            invert = True
-
-        if check_scope.command == 'if' and check_scope.inputs:
-            types = evaluator.eval_statement(check_scope.inputs[0])
-            values = set(x.py__bool__() for x in types)
-            if len(values) == 1:
-                reachable = Status.lookup_table[values.pop()]
-                if invert:
+                reachable = _check_flow(evaluator, check_scope)
+                if reachable in (REACHABLE, UNSURE):
+                    break
             reachable = reachable.invert()
-                if reachable is UNREACHABLE:
-                    return UNREACHABLE
         else:
-                return UNSURE
-        elif check_scope.command in ('try', 'except', 'finally'):
-            reachable = UNSURE
+            reachable = _check_flow(evaluator, element_scope)
 
-    if base_scope != element_scope and base_scope != check_scope.parent:
+    # Only reachable branches need to be examined further.
+    if reachable in (UNREACHABLE, UNSURE):
+        return reachable
+
+    if base_scope != element_scope and base_scope != element_scope.parent:
         return reachable & break_check(evaluator, base_scope, element_scope.parent)
     return reachable
+
+
+def _check_flow(evaluator, flow):
+    if flow.command in ('elif', 'if') and flow.inputs:
+        types = evaluator.eval_statement(flow.inputs[0])
+        values = set(x.py__bool__() for x in types)
+        if len(values) == 1:
+            return Status.lookup_table[values.pop()]
+        else:
+            return UNSURE
+    elif flow.command in ('try', 'except', 'finally', 'while'):
+        return UNSURE

test/completion/flow_analysis.py

@@ -20,3 +20,63 @@ def try_except(x):
 
 #? float() str()
 try_except(1)
+
+
+#  Exceptions are not analyzed. So check both if branches
+def try_except(x):
+    try:
+        if 0:
+            return 1
+        else:
+            return ''
+    except AttributeError:
+        return 1.0
+
+#? float() str()
+try_except(1)
+
+
+# -----------------
+# elif
+# -----------------
+
+def elif_flows1(x):
+    if False:
+        return 1
+    elif True:
+        return 1.0
+    else:
+        return ''
+
+#? float()
+elif_flows1(1)
+
+
+def elif_flows2(x):
+    try:
+        if False:
+            return 1
+        elif 0:
+            return 1.0
+        else:
+            return ''
+    except ValueError:
+        return set
+
+#? str() set
+elif_flows2(1)
+
+
+def elif_flows3(x):
+    try:
+        if True:
+            return 1
+        elif 0:
+            return 1.0
+        else:
+            return ''
+    except ValueError:
+        return set
+
+#? int() set
+elif_flows3(1)