Improvements for getting touched functions in JavaScript code (#1187)

* Skip error entries and anonymous functions right away

* Add a few comments to explain get_touched_functions

* Don't stop at the first function containing a line

To support functions which are defined inside other functions.

* Skip a function when it has already been added to the set

* Add some get_touched_functions tests with JavaScript code

bugbug/repository.py

@@ -262,18 +262,24 @@ def get_touched_functions(path, deleted_lines, added_lines, content):
     touched_function_names = set()
 
     functions = function_data["spans"]
+    functions = [
+        function
+        for function in functions
+        if not function["error"] and function["name"] != "<anonymous>"
+    ]
 
     def get_touched(functions, lines):
         last_f = 0
         for line in lines:
             for function in functions[last_f:]:
-                if function["error"] or function["end_line"] < line:
+                # Skip functions which we already passed.
+                if function["end_line"] < line:
                     last_f += 1
-                    continue
 
-                if function["start_line"] <= line:
+                # If the line belongs to this function, add the function to the set of touched functions.
+                elif function["start_line"] <= line:
                     touched_function_names.add(function["name"])
-                    break
+                    last_f += 1
 
     # Get functions touched by added lines.
     get_touched(functions, added_lines)

tests/test_repository.py

@@ -870,3 +870,47 @@ void func2() {
     )
 
     assert touched_functions == {("func2", 5, 7)}
+
+    # top-level and a JavaScript function touched.
+    touched_functions = repository.get_touched_functions(
+        "file.js",
+        [],
+        [1, 4],
+        """let j = 0;
+
+function func() {
+let i = 0;
+}""",
+    )
+
+    assert touched_functions == {("func", 3, 5)}
+
+    # An anonymous function touched inside another function.
+    touched_functions = repository.get_touched_functions(
+        "file.jsm",
+        [],
+        [4],
+        """function outer_func() {
+let i = 0;
+let f = function() {
+  let j = 0;
+}();
+}""",
+    )
+
+    assert touched_functions == {("outer_func", 1, 6)}
+
+    # A function touched inside another function.
+    touched_functions = repository.get_touched_functions(
+        "file.jsm",
+        [],
+        [4],
+        """function outer_func() {
+let i = 0;
+function inner_func() {
+  let j = 0;
+}
+}""",
+    )
+
+    assert touched_functions == {("outer_func", 1, 6), ("inner_func", 3, 5)}