Allow to disable and enable file starting from the first line

docs/releasenotes/4.0.0.rst

@@ -274,3 +274,8 @@ Bugs
 
 - Keyword name will no longer be prefixed with continuation marks (``...``) if name was longer than line length limit (#494)
 - It is now safe to use Tasks sections with ``MergeAndOrderSections`` transformer with Robot Framework 6.0+ (#490)
+- It is now possible to use disabler in the first line and enable it later (previously the whole file was always ignored) (#479)::
+
+    # robotidy: off
+    # robotidy: on
+    *** Settings ***

robotidy/disablers.py

@@ -68,6 +68,13 @@ def __init__(self, start_line, end_line, file_end):
         self.lines = []
         self.disabled_headers = set()
 
+    @property
+    def file_disabled(self):
+        """Check if file is disabled. Whole file is only disabled if the first line contains one line disabler."""
+        if not self.lines:
+            return False
+        return self.lines[0] == (1, 1)
+
     def add_disabler(self, start_line, end_line):
         self.lines.append((start_line, end_line))
 
@@ -128,9 +135,9 @@ def visit_File(self, node):  # noqa
         self.disablers = DisabledLines(self.start_line, self.end_line, node.end_lineno)
         self.disablers.parse_global_disablers()
         self.stack = []
-        self.file_disabled = False
         self.generic_visit(node)
         self.disablers.sort_disablers()
+        self.file_disabled = self.disablers.file_disabled
 
     def visit_SectionHeader(self, node):  # noqa
         for comment in node.get_tokens(Token.COMMENT):
@@ -143,26 +150,20 @@ def visit_SectionHeader(self, node):  # noqa
     def visit_TestCase(self, node):  # noqa
         self.stack.append(0)
         self.generic_visit(node)
-        if self.file_disabled:  # stop visiting if whole file is disabled
-            return
         self.close_disabler(node.end_lineno)
 
     def visit_Try(self, node):  # noqa
         self.generic_visit(node.header)
         self.stack.append(0)
         for statement in node.body:
             self.visit(statement)
-        if self.file_disabled:  # stop visiting if whole file is disabled
-            return
         self.close_disabler(node.end_lineno)
         tail = node
         while tail.next:
             self.generic_visit(tail.header)
             self.stack.append(0)
             for statement in tail.body:
                 self.visit(statement)
-            if self.file_disabled:  # stop visiting if whole file is disabled
-                return
             end_line = tail.next.lineno - 1 if tail.next else tail.end_lineno
             self.close_disabler(end_line=end_line)
             tail = tail.next
@@ -181,11 +182,8 @@ def visit_Statement(self, node):  # noqa
                     return
                 self.disablers.add_disabler(self.stack[index], node.lineno)
                 self.stack[index] = 0
-            else:
-                if node.lineno == 1 and index == 0:
-                    self.file_disabled = True
-                elif not self.stack[index]:
-                    self.stack[index] = node.lineno
+            elif not self.stack[index]:
+                self.stack[index] = node.lineno
         else:
             # inline disabler
             if self.any_disabler_open():

tests/utest/test_disablers.py

@@ -1,4 +1,3 @@
-import re
 from pathlib import Path
 from unittest.mock import Mock
 
@@ -52,7 +51,8 @@ def test_is_node_disabled(check_start, check_end, start_line, end_line, lines, f
 @pytest.mark.parametrize(
     "test_file, expected_lines, file_disabled, rf_version",
     [
-        ("file_disabled.robot", [(14, 15)], True, 4),
+        ("file_disabled.robot", [(1, 1), (14, 15)], True, 4),
+        ("file_disabled_and_enabled.robot", [(1, 2), (15, 16)], False, 4),
         ("test.robot", [(13, 14), (25, 37), (30, 33), (40, 41), (46, 48), (57, 58), (67, 67)], False, 5),
         ("open_disabler_in_section.robot", [(5, 8), (13, 15), (20, 23)], False, 4),
         ("empty.robot", [], False, 4),

tests/utest/testdata/disablers/file_disabled_and_enabled.robot

@@ -0,0 +1,24 @@
+# robotidy: off
+# robotidy: on
+*** Settings ***
+Library  SeleniumLibrary
+
+Metadata    Key    Value
+
+*** Test Cases ***
+Test
+    [Documentation]     This is doc
+    Step
+    FOR    ${var}    IN RANGE    10
+        IF    $condition
+            WHILE    ${arg}
+                ${return}    Keyword    ${value}
+                ...    ${other_value}    # robotidy: off
+            END
+        ELSE IF
+            Step    ${arg}
+            ...    value
+            Step 2
+            #  comment
+        END
+    END