rules.toml

# Copyright (c) 2023 Uber Technologies, Inc.
# 
# <p>Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of the License at
# <p>http://www.apache.org/licenses/LICENSE-2.0
# 
# <p>Unless required by applicable law or agreed to in writing, software distributed under the
# License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
# express or implied. See the License for the specific language governing permissions and
# limitations under the License.

# The language specific rules in this file are applied after the API specific change has been performed.

# Before: 
# (true)
# After 
# true

[[rules]]
name = "simplify_parenthesized_expression"
query = "(parenthesized_expression ([(true) (false) (identifier)] @expression)) @p_expr"
replace = "@expression"
replace_node = "p_expr"
is_seed_rule = false
groups = ["boolean_expression_simplify"]

# Before : 
#  if (true) { doSomething(); }
# After :
#  { doSomething(); } 
# 
# Before : 
#  if (true) { doSomething(); } else { doSomethingElse();}
# After :
#  { doSomething(); } 
#
[[rules]]
groups = ["if_cleanup"]
name = "simplify_if_statement_true"
query = """
(
    (if_statement
        condition : (condition (true))
        consequence : ((statement) @consequence))
@if_statement)
"""
replace = "@consequence"
replace_node = "if_statement"
is_seed_rule = false

# Before : 
#  if (true) { doSomething(); } else { doSomethingElse();}
# After :
#  { doSomethingElse(); } 
#
# Before : 
#  if (true) { doSomething(); }
# After :
#  
[[rules]]
groups = ["if_cleanup"]
name = "simplify_if_statement_false"
query = """
(
    (if_statement
        condition : (condition (false))
        consequence : ((statement) @consequence)
        alternative : ((_) @alternative) ?)
@if_statement)"""
replace = "@alternative"
replace_node = "if_statement"
is_seed_rule = false

# Before : 
#  !false
# After :
#  true 
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_not_false"
query = """
(
    (unary_expression
        operator: "!"
        operand: (false))
@unary_expression)
"""
replace = "true"
replace_node = "unary_expression"
is_seed_rule = false

# Before : 
#  !true
# After :
#  false
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_not_true"
query = """
(
    (unary_expression
        operator: \"!\"
        operand: (true))
@unary_expression)
"""
replace = "false"
replace_node = "unary_expression"
is_seed_rule = false

# Before : 
#  {
#     someStepsBefore();
#     {
#        someSteps();
#     }   
#     someStepsAfter();
#  }
# After :
#  {
#     someStepsBefore();
#        someSteps();
#     someStepsAfter();
#  }
#
[[rules]]
name = "remove_unnecessary_nested_block"
query = """
([
    (block
        (
            (_)* @pre
            (block (_)* @nested.statements) @nested.block
            (_)* @post
        )
    )
    (constructor_body
        (
            (_)* @pre
            (block (_)* @nested.statements) @nested.block
            (_)* @post
        )
    )
    ]@block)"""
replace = "@nested.statements"
replace_node = "nested.block"
is_seed_rule = false

# Before : 
#  true && abc()
# After :
#  abc()
#

[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_true_and_something"
query = """
(
    (binary_expression
        left: (true)
        operator:"&&"
        right : (_) @rhs) 
) @binary_expression
"""
replace = "@rhs"
replace_node = "binary_expression"
is_seed_rule = false

# Before :
#  abc() && true
# After :
#  abc()
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_something_and_true"
query = """
(
    (binary_expression
        left : (_) @lhs
        operator:"&&"
        right: (true)
    )
@binary_expression)"""
replace = "@lhs"
replace_node = "binary_expression"
is_seed_rule = false

# Before :
#  false && abc()
# After :
#  false
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_false_and_something"
query = """
(
    (binary_expression
        left: (false)
        operator : "&&"
        right : (_) @rhs
    )
@binary_expression)"""
replace = "false"
replace_node = "binary_expression"
is_seed_rule = false

# Before :
#  abc && false
# After :
#  false
#
[[rules]]
name = "simplify_something_and_false"
groups = ["boolean_expression_simplify"]
query = """
(
    (binary_expression
        left : (_) @lhs
        operator : "&&"
        right: (false)) @binary_expression
)
"""
replace = "false"
replace_node = "binary_expression"
is_seed_rule = false

# Before :
#  abc || true
# After :
#  true
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_something_or_true"
query = """
(
    (binary_expression
        left : (_) @lhs
        operator:"||"
        right: (true)
    )
@binary_expression)"""
replace = "true"
replace_node = "binary_expression"
is_seed_rule = false

# Before :
#  true || abc()
# After :
#  true
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_true_or_something"
query = """
(
    (binary_expression
        left : (true)
        operator:"||"
        right: (_) @rhs
    )
@binary_expression)
"""
replace = "true"
replace_node = "binary_expression"
is_seed_rule = false

# Before: 
#  abc() || false
# After :
#  abc()
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_something_or_false"
query = """(
(
    binary_expression
        left : (_) @lhs
        operator:"||"
        right: (false)
    )
@binary_expression)"""
replace = "@lhs"
replace_node = "binary_expression"
is_seed_rule = false

# Before: 
#  false || abc()
# After :
#  abc()
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_false_or_something"
query = """
(
    (binary_expression
        left : (false)
        operator:"||"
        right: (_) @rhs
    )
@binary_expression)"""
replace = "@rhs"
replace_node = "binary_expression"
is_seed_rule = false


# Before: 
#  (x) == x
#  x == (x)
#  x == x
# After :
#  true
#  true
#  true
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_equals_equals_true"
query = """
(
    (binary_expression
        left : [(parenthesized_expression (_) @lhs) (_) @lhs]
        operator:"=="
        right: [(parenthesized_expression (_) @rhs) (_) @rhs]
    )
@binary_expression
(#eq? @lhs @rhs)
)"""
replace = "true"
replace_node = "binary_expression"
is_seed_rule = false


# Before: 
#  false == true 
#  true == false
# After :
#  false
#  false
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_equals_equals_false"
query = """
(
    (binary_expression
        left : [(false) @lhs (true) @lhs (string_literal) (decimal_integer_literal) @lhs (decimal_floating_point_literal) @lhs]
        operator:"=="
        right: [(false) @rhs (true) @rhs (string_literal) @rhs (decimal_integer_literal) @rhs (decimal_floating_point_literal) @rhs]
    )
@binary_expression
(#not-eq? @lhs @rhs)
)"""
replace = "false"
replace_node = "binary_expression"
is_seed_rule = false


# Before: 
#  false != false 
#  true != true
# After :
#  false
#  false
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_not_equals_false"
query = """
(
    (binary_expression
        left : [(false) @lhs (true) @lhs (string_literal) (decimal_integer_literal) @lhs (decimal_floating_point_literal) @lhs]
        operator:"!="
        right: [(false) @rhs (true) @rhs (string_literal) @rhs (decimal_integer_literal) @rhs (decimal_floating_point_literal) @rhs]
    )
@binary_expression
(#eq? @lhs @rhs)
)"""
replace = "false"
replace_node = "binary_expression"
is_seed_rule = false


# Before: 
#  false != true 
#  true != false
# After :
#  true
#  true
#
[[rules]]
groups = ["boolean_expression_simplify"]
name = "simplify_not_equals_true"
query = """
(
    (binary_expression
        left : [(false) @lhs (true) @lhs (string_literal) (decimal_integer_literal) @lhs (decimal_floating_point_literal) @lhs]
        operator:"!="
        right: [(false) @rhs (true) @rhs (string_literal) @rhs (decimal_integer_literal) @rhs (decimal_floating_point_literal) @rhs]
    )
@binary_expression
(#not-eq? @lhs @rhs)
)"""
replace = "true"
replace_node = "binary_expression"
is_seed_rule = false

# Before :
#  {
#    something();
#    return 10;
#    somethingMore();
#    return 100;
#  } 
# After :
#  {
#    something();
#    return 10;
#  } 
#
[[rules]]
name = "delete_all_statements_after_return"
query = """(
        (block  ((statement)* @pre)
         ((return_statement) @r)
         ((statement)+ @post)) @b)"""
replace = ""
replace_node = "post"
is_seed_rule = false


# Before :
#  condition ? abc() : abc();
# After :
#  abc()
#
[[rules]]
groups = ["if_cleanup"]
name = "simplify_ternary_similar_consequent_alternative"
query = """
(
    (ternary_expression condition: (_)
        consequence: (_)* @consequence
        alternative: (_)* @alternative)
@ternary_expression
(#eq? @consequence @alternative)
)"""
replace = "@consequence"
replace_node = "ternary_expression"
is_seed_rule = false

# Before :
#  true ? abc() : def();
# After :
#  abc()
#
[[rules]]
groups = ["if_cleanup"]
name = "simplify_ternary_operator_true"
query = """
(
    (ternary_expression condition: (true)
        consequence: (_)* @consequence
        alternative: (_)* @alternative)
@ternary_expression)"""
replace = "@consequence"
replace_node = "ternary_expression"
is_seed_rule = false

# Before :
#  false ? abc() : def();
# After :
#  def()
#
[[rules]]
groups = ["if_cleanup"]
name = "simplify_ternary_operator_false"
query = """
(
    (ternary_expression condition: (false)
        consequence: (_)* @consequence
        alternative: (_)* @alternative)
@ternary_expression)"""
replace = "@alternative"
replace_node = "ternary_expression"
is_seed_rule = false

[[rules]]
name = "delete_empty_enum_declaration"
query = """
(enum_declaration) @enum_declaration"""
replace = ""
replace_node = "enum_declaration"
is_seed_rule = false
[[rules.filters]]
enclosing_node = "(enum_declaration) @ed"
not_contains = ["(enum_constant) @ec"]


# This rule deltes all the content of the file if it contains 
# no type declaration, enum declaration and annotation type declaration. 
#
# It optionally captures the @package_name for the deleted file. 
[[rules]]
name = "delete_file_with_no_type_declarations"
query = """(
(program 
  (package_declaration (_) @package_name)?) @program)"""
replace = ""
replace_node = "program"
is_seed_rule = false
[[rules.filters]]
enclosing_node = "(program) @c_program"
not_contains = [
  "(enum_declaration) @c_enum_declaration",
  "(class_declaration) @c_class_declaration",
  "(interface_declaration) @c_interface_declaration",
  "(annotation_type_declaration) @c_annotation_type_declaration",
  "(module_declaration) @c_module_declaration",
  "(record_declaration) @c_arecord_declaration",
]

# This rule is part (and entry point) for the inline local variable cleanup. Example: 
# 
# Before :
# public foo someMethod() { 
#  boolean isFlag = true; 
#  somethingElse();
# }
#
# After :
# public foo someMethod() { 
#  somethingElse();
# }
#
# Before inlining a variable we need to ensure that the variable is not re assigned anywhere within the method body 
# to a value which is not the same as the initializer of variable we are inlining..
# Note the below negative example of this rule where the variable `isFlag` is re-assigned to the value `getFlagStatus()` while it's 
# initializer is `true`. In such a scenario the variable `isFlag` should not be inlined.
# 
# public foo someMethod() { 
#  boolean isFlag = true; 
#  isFlag = getFlagStatus();
#  somethingElse();
# }
#

[[rules]]
name = "delete_variable_declaration"
query = """
(
((local_variable_declaration 
                declarator: (variable_declarator 
                                    name: (_) @variable_name
                                    value: [(true) (false)] @init)) @variable_declaration)
)
"""
replace = ""
replace_node = "variable_declaration"
is_seed_rule = false

# Check if there is no assignment where the variable @variable_name is 
# assigned to a value other than @init, within the method body
# Please note that the tree-sitter queries in the filter uses holes (i.e. `@variable_name` and `@init`).
# These holes will be filled contextually based on the code snippet matched to `rule.query
[[rules.filters]]
enclosing_node = "[(method_declaration) (constructor_declaration)] @md"
not_contains = ["""
(
((assignment_expression
                    left: (_) @a.lhs
                    right: (_) @a.rhs) @assignment)
(#eq? @a.lhs "@variable_name")
(#not-eq? @a.rhs "@init")
)"""]

# This rule is part (and entry point) of the inline field declaration cleanup.
# Same as the rule `delete_variable_declaration`, but applicable to fields.
[[rules]]
name = "delete_field_declaration"
query = """
(
((field_declaration 
                declarator: (variable_declarator 
                                    name: (_) @variable_name
                                    value: [(true) (false)] @init)) @field_declaration)
)
"""
replace = ""
replace_node = "field_declaration"
is_seed_rule = false

# Check if there is no assignment where the variable @variable_name is 
# assigned to a value other than @init, within the method body
[[rules.filters]]
enclosing_node = "(class_declaration) @cd"
not_contains = ["""(
((assignment_expression
                    left: (_) @a.lhs
                    right: (_) @a.rhs) @assignment)
(#eq? @a.lhs "@variable_name")
(#not-eq? @a.rhs "@init")
)"""]

# This rule is part of inline variable declaration and field declaration cleanup. 
# Delete assignment for a particular (@variable_name, @init) if: 
# (i) If the enclosing method does not contain a variable declaration for @variable_name
# (ii) If the Rhs of the assignment is same as the initializer of the variable it previously inlined.
[[rules]]
name = "delete_boolean_assignments_for_variable"
query = """
(
(expression_statement (assignment_expression
                                left: (_) @l
                    right: (_) @r)) @expression_statement
(#eq? @l "@variable_name")
(#eq? @r "@init")
) 
"""
replace = ""
replace_node = "expression_statement"
is_seed_rule = false
holes = ["variable_name", "init"]
# The enclosing methode declaration should not contain a local variable decalration named "@variable_name"
# which is initialized to "@init".
[[rules.filters]]
enclosing_node = "[(method_declaration) (constructor_declaration)] @md"
not_contains = ["""(
((local_variable_declaration 
                declarator: (variable_declarator 
                                    name: (_) @vdcl.lhs
                                    value: (_) @vdcl.init)) @field_declaration)
(#eq? @vdcl.lhs "@l")
)"""]

# This rule is part (and entry point) of the inline variable / field declaration. 
# delete assignment if 
# (i) if it is the only assignment in the entire class in the enclosing class
# (ii) There is a field declaration with the same rhs as this assignment in the enclosing class
# (iii) There is no local variable declaration of the same name in the enclosing method
[[rules]]
name = "delete_parent_assignment"
query = """
(
(expression_statement (assignment_expression
                                left: (_) @variable_name
                    right: (_) @init)) @expression_statement
) 
"""
replace = ""
replace_node = "expression_statement"
is_seed_rule = false
# The enclosing methode declaration should not contain a local variable decalration named "@variable_name"
[[rules.filters]]
enclosing_node = "(method_declaration) @md"
not_contains = [
  """(
((local_variable_declaration
                declarator: (variable_declarator 
                                    name: (_) @vdcl.lhs
                                    value: (_)? @vdcl.init)) @variable_declaration)
(#eq? @vdcl.lhs "@variable_name")
)""",
]
[[rules.filters]]
# There should exist no field declaration named `@variable_name` and
# there should be no assignments to @variable_name that are not same as `@init`.
enclosing_node = "(class_declaration) @cd"
not_contains = ["""(
((assignment_expression
                    left: (_) @a.lhs
                    right: (_) @a.rhs) @a)
(#eq? @a.lhs "@variable_name")
(#not-eq? @a.rhs "@init")
)""", """(
((field_declaration 
                declarator: (variable_declarator 
                                    name: (_) @fdcl.lhs
                                    value: (_) @fdcl.init)) @field_declaration)
(#eq? @fdcl.lhs "@variable_name")
(#not-eq? @fdcl.init "@init")
)"""]

# Replace identifier with value if :
# (i) There is no local variable declaration in the enclosing method with the name as the identifier 
# TODO: Add field filter
[[rules]]
name = "replace_identifier_with_value"
query = """
(
(identifier) @identifier
(#eq? @identifier "@variable_name")
)
"""
replace = "@init"
replace_node = "identifier"
holes = ["variable_name", "init"]
is_seed_rule = false
[[rules.filters]]
# There should exist no local variable declaration named `@identifer`
enclosing_node = "[(method_declaration) (constructor_declaration)] @md"
not_contains = ["""(
((local_variable_declaration 
                declarator: (variable_declarator 
                                    name: (_) @vdcl.lhs
                                    value: (_) @vdcl.init)) @field_declaration)
(#eq? @vdcl.lhs "@identifier")
)"""]

# Dummy rule that acts as a junction for all boolean based cleanups
# Let's say you want to define rules from A -> B, A -> C, D -> B, D -> C, ... 
# A pattern here is - if there is an outgoing edge to B there is another to C.
# In these cases, you can use a dummy rule X as shown below:
# X -> B, X - C, A -> X, D -> X, ...
[[rules]]
name = "boolean_literal_cleanup"
is_seed_rule = false

# Dummy rule that acts as a junction for all statement based cleanups
[[rules]]
name = "statement_cleanup"
is_seed_rule = false