Custom changes

Custom checkers

EduLint provides custom checkers to report more problems frequent in novice code. It does so by extending Pylint with extra plugins. The checkers can therefore be invoked in the standard Pylint manner (e.g. using --enable or --disable) on the Edulint’s pylint option.

Long Code

This section details messages emmited by the long-code checker.

Message name	Format	Description
long-script	Too much code outside of functions or classes (%d which is over %d statements).	Emitted when there are too many lines of code on the top level that are not import or function or class definition.
long-function	Function '%s' is too long (%d which is over %d statements).	Emitted when there are too many statements inside a function definition.

No Global Variables

This section details messages emmited by the no-global-variables checker.

Message name	Format	Description
no-global-vars	Do not use global variables; you use %s, modifying it for example at line %i.	Emitted when the code uses global variables.

No Duplicate Code

This section details messages emmited by the no-duplicate-code checker.

Message name	Format	Description
identical-if-branches	The branches of the 'if' statement are identical. Remove the 'if' if it is on purpose, or change the branches if not.	Emitted when all branches of an ‘if’ statement contain identical code.
identical-if-branches-part	Identical code inside all if's branches, move %d lines %s the if.	Emitted when identical code starts or ends all branches of an if statement.
identical-seq-ifs	Identical code inside %d consecutive ifs, join their conditions using 'or'.	Emitted when several consecutive if statements have identical bodies and thus can be joined by or in their conditions.
identical-seq-elifs	Identical code inside %d consecutive elifs, join their conditions using 'or'.	Emitted when several consecutive elif branches have identical bodies and thus their conditions can be joined by or.
similar-block-to-function	There are %d repetitions of %d similar statements, starting on lines %s. Extract them to a helper function.	Emitted when similar blocks can be deduplicated using a helper function.
similar-block-to-loop-range	There are %d repetitions of %d similar statements, which can be simplified using a loop. Consider iterating over '%s'.	Emitted when similar sequential blocks can be deduplicated using a loop.
similar-block-to-loop-collection	There are %d repetitions of %d similar statements, which can be simplified using a loop. Consider iterating over '%s'.	Emitted when similar sequential blocks can be deduplicated using a loop.
similar-block-to-loop-merge	The body of the loop contains duplicate blocks, starting on lines %s. Avoid the duplication by repeating the outer loop %s times.	Emitted when the body can be simplified using a loop and the extra iterations can be performed by iterating the outer loop more times.
similar-block-to-call	Call the existing function '%s' instead of repeating its body.	Emitted when a block can be replaced by a call to an existing function.
similar-if-to-use	Consider using condition directly instead of literals 'True'/'False', if the if's body has no effect on the condition's value.	Emitted when the two branches of an ‘if’ statement differ only in True/False, so the if’s condition can be used directly.
similar-if-into-block	The branches of the 'if' statement are similar. Move the 'if' into the branches, so that it only contains lines %s, but only if the if's body has no effect on the condition's value.	Emitted when an ‘if’ statement wraps too long part of a block (similar to identical-if-branches-part, but this one can suggest moving if into a for loop, for example).
similar-if-to-untwisted	The branches of the 'if' statement are similar. Use condition '%s' to avoid the duplication.	Emitted when an ‘if’ statement has an if statement in each branch and the nested statements have the same branches, only swapped.
similar-if-to-expr	The branches of the 'if' statement are similar. Use if expression to decide between the different values (i.e., "%s"), but only if the if's body has no effect on the condition's value.	Emitted when the duplication between if statement’s branches can be avoided using the if expression.
similar-if-to-extracted	The branches of the 'if' statement are similar. Use helper variables to store the values that differ between the branches, or create a helper function.	Emitted when the duplication between if statement’s branches can be avoided using helper variables or functions.
similar-if-to-list	The if statements can be avoided using a list.	Emitted when duplication between conditions and branches of if statements can be avoided using a list.
similar-if-to-dict	The if statements can be avoided using a dictionary.	Emitted when duplication between conditions and branches of if statements can be avoided using a dictionary.

Local Defects

This section details messages emmited by the local-defects checker.

Message name	Format	Description
noop	Should never be emitted	Never emitted, just to use if all other checks are disabled
use-append	Use %s.append(%s) instead of %s.	Emitted when code extends list by a single argument instead of appending it.
use-integral-division	Use integral division //.	Emitted when the code uses float division and converts the result to int.
use-isdecimal	Use isdecimal to test if string contains a number.	Emitted when the code uses isdigit or isnumeric.
no-loop-else	Do not use %s loop with else.	Emitted when the code contains loop with else block.
use-elif	Use elif.	Emitted when the code contains else: if construction instead of elif. Might return a false positive if the code mixes tabs and spaces.
at-most-one-iteration-for-loop	The for loop makes %s.	Emitted when a for loop would always perform at most one iteration.
no-repeated-op	Use %s instead of repeated %s in %s.	Emitted when the code contains repeated adition/multiplication instead of multiplication/exponentiation.
redundant-arithmetic	Redundant arithmetic: %s	Emitted when there is redundant arithmetic (e.g. +0, *1) in an expression.
use-augmented-assign	Use augmented assignment: '%s %s= %s'	Emitted when an assignment can be simplified by using its augmented version.
do-not-multiply-mutable	Do not multiply list with mutable content.	Emitted when a list with mutable contents is being multiplied.
redundant-elif	Use else instead of elif.	Emitted when the condition in elif is negation of the condition in the if.
unreachable-else	Unreachable else.	Emitted when the else branch is unreachable due to totally exhaustive conditions before.
no-is-bool	Use '%s' directly rather than as '%s'.	Emitted when the is operator is used with a bool value.
use-ord-letter	Use "%s" instead of using the magical constant %i.	Emitted when the code uses a magical constant instead of a string literal.
use-literal-letter	Remove the call to 'ord' and compare to the string directly "%s" instead of using the magical constant %i. Careful, this may require changing the comparison operator.	Emitted when the code uses a magical constant instead of a string literal in a comparison.
use-early-return	Use early return.	Emitted when a long block of code is followed by an else that just returns, breaks or continues.
in-range-instead-of-compare-small	Consider replacing '%s' with '%s'	Emitted when there is a problem like ‘n in range(1, 5, 2)’ and suggests ‘n == 1 or n == 3’.
in-range-instead-of-compare	Consider replacing '%s' with '%s'	Emitted when there is a problem like ‘n in range(1, 10)’ and suggests ‘1 <= n and n < 10’.
in-range-instead-of-compare-step	Consider replacing '%s' with '%s'	Emitted when there is a problem like ‘n in range(1, 10, 2)’ and suggests ‘1 <= n and n < 5 and n % 2 == 1’.

Old No Duplicate Code

This section details messages emmited by the old-no-duplicate-code checker.

Message name	Format	Description
duplicate-if-branches	Identical code inside all if's branches, move %d lines %s the if.	Emitted when identical code starts or ends all branches of an if statement.
duplicate-seq-ifs	Identical code inside %d consecutive ifs, join their conditions using 'or'.	Emitted when several consecutive if statements have identical bodies and thus can be joined by or in their conditions.
duplicate-exprs	A complex expression '%s' used repeatedly (on lines %s). Extract it to a local variable or create a helper function.	Emitted when an overly complex expression is used multiple times.
duplicate-blocks	Duplicate blocks starting on lines %s. Extract the code to a helper function.	Emitted when there are duplicate blocks of code as a body of an if/elif/else/for/while/with/try-except block.
duplicate-sequence	Duplicate sequence of %d repetitions of %d lines of code. Use a loop to avoid this.	Emitted when there is a sequence of similar sub-blocks inside a block that can be replaced by a loop.

Invalid_For_Target

This section details messages emmited by the invalid_for_target checker.

Message name	Format	Description
invalid-for-target	For loop or comprehension variable "%s" should not be a part of a larger object.	Used when you have an index variable in a for loop or comprehensionthat is in subscript or object attribute form

One_Iteration

This section details messages emmited by the one_iteration checker.

Message name	Format	Description
one-iteration	This loop will only ever run for one iteration	Reported when the loop body always ends the loop in its first iteration (e.g., by returning or using the “break” keyword).

Shadowing_In_Comprehension

This section details messages emmited by the shadowing_in_comprehension checker.

Message name	Format	Description
shadowing-in-comprehension	Comprehension variable '%s' shadows a variable in an outer scope	Used when there is shadowing inside a comprehension

Top_Level_Code

This section details messages emmited by the top_level_code checker.

Message name	Format	Description
forbidden-top-level-code	Forbidden top-level code found on line %s	Used when you write top-level code that is not allowed. The allowed top-level code includes imports, definitions, and assignments.

Simplifiable If

This section details messages emmited by the simplifiable-if checker.

Message name	Format	Description
simplifiable-if-return	The if statement can be replaced with 'return %s'	Emitted when the condition of an if statement can be returned directly (possibly negated).
simplifiable-if-return-conj	The if statement can be replaced with 'return %s'	Emitted when the condition of an if statement and the returned values can be combined using logical operators.
simplifiable-if-assignment	The conditional assignment can be replaced with '%s = %s'	Emitted when the condition of an if statement can be assigned directly (possibly negated).
simplifiable-if-assignment-conj	The conditional assignment can be replaced with '%s = %s'	Emitted when the condition of an if statement and the assigned values can be combined using logical operators.
simplifiable-if-expr	The if expression can be replaced with '%s'	Emitted when the condition of an if expression can be returned directly (possibly negated).
simplifiable-if-expr-conj	The if expression can be replaced with '%s'	Emitted when the condition of an if expression and the returned values can be combined using logical operators.
simplifiable-if-pass	Use 'if %s: <else body>' instead of 'pass'	Emitted when there is an if condition with a pass in the positive branch.
no-value-in-one-branch-return	Both branches should return a value explicitly (one returns implicit None)	Emitted when one branch returns a value and the other just returns.
simplifiable-if-nested	The if statement can be merged with the nested one to 'if %s:'	Emitted when the condition of an if statement can be merged with its nested if’s condition using logical operators.
simplifiable-if-seq	The if statement can be merged with the following one to 'if %s:'	Emitted when the condition of an if statement can be merged with the next if’s condition using logical operators.
simplifiable-with-abs	'%s' can be replaced with '%s'	Emitted when there is a problem like x < 4 and x > -4 and suggests abs(x) < 4.
redundant-compare-in-condition	'%s' can be simplified to '%s'. Simplify the condition if it is on purpose, or change it if it was not.	Emitted when there is a problem like x > 4 or x > 3 and suggests x > 3. (ie min{4, 3})
redundant-compare-avoidable-with-max-min	'%s' can be replaced with '%s'	Emitted when there is a problem like ‘x > a and x > b’ and suggests x > max(a, b).
using-compare-instead-of-equal	'%s' can be replaced with '%s'	Emitted when there is a problem like x >= 0 and x <= 0 and suggests x == 0.
simplifiable-test-by-equals	'%s' can be replaced with '%s'	Emitted when there is a problem like ‘x % 2 == 0 and y % 2 == 0 or x % 2 == 1 and y % 2 == 1’ and suggests ‘x % 2 == y % 2’.
redundant-condition-part	'%s' can be replaced with '%s'	[REQUIRES Z3] Emitted when there is a problem like ‘A or B’, where A implies B and suggests to simplify the condition to just ‘B’
unreachable-elif-else	This '%s' is unreachable.	[REQUIRES Z3] Emitted when the ‘else/elif’ branch is unreachable due to totally exhaustive conditions before.
condition-always-true-in-elif	This 'elif' can be replaced with just 'else'.	[REQUIRES Z3] Emitted when a body of ‘elif’ in if statement is always executed when reached.
redundant-condition-part-in-elif	'%s' can be replaced with '%s', because some operands of the '%s' are always %s.	[REQUIRES Z3] Emitted when a test condition in ‘elif’ can be simplified, because when the control flow reaches this ‘elif’ we know that some parts of this condition are True (when the condition is ‘and’) or False (when the condition is ‘or’)
redundant-condition-part-in-elif-reorder	Conditions in the if statement can be simplified by reordering elif blocks, we suggest this order: '%s' with these possibly simplified test conditions respectively: '%s'.	[REQUIRES Z3] Emitted when elifs in if-statement can be rearanged to get simpler conditions. (by moving some condition higher, parts of conditions below it can become redundant)
condition-always-false-in-elif	The body of this 'elif' is never executed, because its condition is always False when reached.	[REQUIRES Z3] Emitted when a condition in elif is always False, when reached.
condition-always-true-or-false	This condition is always %s.	[REQUIRES Z3] Emitted when a condition is always True/False regardless of assignment to variables.
use-if-elif-else	The next %d if statements after this one can be elif statements.	[REQUIRES Z3] Emmited when there are at least two consecutive if-statements that can be merged into just one if-elif-statement. But no variables from test conditions are modified.
use-if-elif-else-modifying	The next %d if statements after this one can be elif statements.	[REQUIRES Z3] Emmited when there are at least two consecutive if-statements that can be merged into just one if-elif-statement. But some variable from test conditions is modified.

Unsuited Loop

This section details messages emmited by the unsuited-loop checker.

Message name	Format	Description
no-while-true	The while condition can be replaced with '<negated %s>'	Emitted when the condition of a while loop is ‘True’ unnecessarily.
use-tighter-boundaries	Use tighter range boundaries, the %s iteration never happens.	Emitted when the boundaries of a range can be made tighter.
modifying-iterated-structure	Iterated structure %s is being modified inside the for loop body. Use while loop or iterate over a copy.	Emitted when the structure that is being iterated over is being modified in the for loops body.
changing-control-variable	Changing the control variable %s of a for loop has no effect.	Emitted when the control variable of a for loop is being changed.
use-for-loop	You should use for loop instead of this form of while loop.	Emitted when a while loop can be transformed into a for loop.
loop-shadows-control-variable	Inner for loop shadows outer for loop's control variable %s.	Emitted when a for loop shadows control variable of an outer for loop.
use-foreach	Iterate directly: "for var in %s" (with appropriate name for "var")	Emitted when a for-range loop is used while a for-each loop would suffice.
use-enumerate	Iterate using enumerate: "for %s, var in enumerate(%s)" (with appropriate name for "var")	Emitted when a for-range loop is used with the element at each index is accessed as well.
explicit-infinite-loop	This while loop is infinite.	[REQUIRES Z3] Emitted when a while loop condition is `True` and never terminates. Warning: If there is called some function that can raise some exception then this checker might not see it.
implicit-infinite-loop	This while loop is infinite.	[REQUIRES Z3] Emitted when a while loop never terminates (when the loop condition is once True it will stay True forever). Warning: If there is called some function that can raise some exception then this checker might not see it.

Tweakers

Tweaked message	Effects
disallowed-name	when allowed-onechar-names is enabled, complains on all single-character variable names, encouraging choosing a different name