FilesExpand file tree

main

/

DanglingElse.ql

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

85 lines (78 loc) · 2.91 KB

main

/

DanglingElse.ql

Copy path

Top

File metadata and controls

• Code
• Blame

85 lines (78 loc) · 2.91 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

/**

* @name Misleading indentation of dangling 'else'

* @description The 'else' clause of an 'if' statement should be aligned with the 'if' it belongs to.

* @kind problem

* @problem.severity warning

* @id js/misleading-indentation-of-dangling-else

* @tags quality

* maintainability

* readability

* statistical

* non-attributable

* external/cwe/cwe-483

* @precision very-high

*/

import javascript

/**

* A token that is relevant for this query, that is, an `if`, `else` or `}` token.

*/

class RelevantToken extends Token {

RelevantToken() { exists(string v | v = this.getValue() | v = "if" or v = "else" or v = "}") }

}

/**

* Holds if `prev` precedes `tk` on the same line, where `val` is the value of `tk`

* and `prevVal` is the value of `prev`.

*/

predicate prevTokenOnSameLine(RelevantToken tk, string val, Token prev, string prevVal) {

val = tk.getValue() and

prev = tk.getPreviousToken() and

prev.getLocation().getEndLine() = tk.getLocation().getStartLine() and

prevVal = prev.getValue()

}

/**

* Gets the semantic indentation of token `tk`.

*

* The semantic indentation of a token `tk` is defined as follows:

*

* 1. If `tk` is the first token on its line, its semantic indentation is its start column.

* 2. Otherwise, if `tk` is an `if` token preceded by an `else` token, or an `else` token

* preceded by an `}` token, its semantic indentation is the semantic indentation of that

* preceding token.

* 3. Otherwise, the token has no semantic indentation.

*

* The intuitive idea is that the `if` token of an `else if` branch is assigned the indentation

* of the preceding `else` token, or even that of the `}` token preceding the `else`, but only

* if these tokens are on the same line as the `if`.

*/

int semanticIndent(RelevantToken tk) {

not prevTokenOnSameLine(tk, _, _, _) and

result = tk.getLocation().getStartColumn()

or

exists(RelevantToken prev |

prevTokenOnSameLine(tk, "if", prev, "else") or

prevTokenOnSameLine(tk, "else", prev, "}")

|

result = semanticIndent(prev)

)

}

/**

* Gets the semantic indentation of the `if` token of statement `i`.

*/

int ifIndent(IfStmt i) { result = semanticIndent(i.getIfToken()) }

/**

* Gets the semantic indentation of the `else` token of statement `i`,

* if any.

*/

int elseIndent(IfStmt i) { result = semanticIndent(i.getElseToken()) }

from IfStmt outer, IfStmt inner, Token outerIf, Token innerIf, Token innerElse, int outerIndent

where

inner = outer.getThen().getAChildStmt*() and

outerIf = outer.getIfToken() and

outerIndent = ifIndent(outer) and

innerIf = inner.getIfToken() and

innerElse = inner.getElseToken() and

outerIndent < ifIndent(inner) and

outerIndent = elseIndent(inner) and

not outer.getTopLevel().isMinified()

select innerElse, "This else branch belongs to $@, but its indentation suggests it belongs to $@.",

innerIf, "this if statement", outerIf, "this other if statement"