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Version: 0.7.0

KCL Errors and Warnings

The articles in this section of the documentation explain the diagnostic error and warning messages that are generated by the KCL.

Important: The KCL can report many kinds of errors and warnings. After an error or warning is found, the build tools may make assumptions about code intent and attempt to continue, so that more issues can be reported at the same time. If the tools make the wrong assumption, later errors or warnings may not apply to your project. When you correct issues in your project, always start with the first error or warning that's reported and rebuild often. One fix may make many subsequent errors go away.

In the following sections you will find:

KCL Syntax Error (E1xxx) : The KCL may reports KCL syntax errors when illegal syntax is used in KCL program.

KCL Compile Error (E2xxx): The KCL may reports KCL compile errors when the KCL program conforms to the KCL syntax but does not conform to the KCL semantics.

KCL Runtime Error (E3xxx): The KCL may report KCL runtime errors when the virtual machine executing a KCL program that passes the compilation.

KCL Compile Warning (W2xxx): When the compiler compiles KCL programs and finds possible potential errors, such warnings will be reported by KCL.

1.1 KCL Syntax Error (E1xxx)

This section mainly includes KCL errors:

ewcodeKCL exceptionmessages
E1001InvalidSyntaxErrorInvalid syntax
E1002KCLTabErrorTab Error
E1003KCLIndentationErrorIndentation Error
E1I37IllegalArgumentSyntaxErrorIllegal argument syntax

InvalidSyntaxError

KCL will report InvalidSyntaxError when KCL has a syntax error.

The ewcode of InvalidSyntaxError is E1001.

For example:

a, b = 1, 2 # Multiple assign is illegal in KCL syntax

The KCL program will cause the following error message.

error[E1001]: InvalidSyntax
--> /syntax_error/general/multiple_assign/case0/main.k:1:2
|
1 | a, b = 1, 2 # Multiple assign is illegal in KCL syntax
| ^ expected statement
|

Possible resolution:

  • Check and fix KCL syntax errors based on the KCL Language Standard

TabError

KCL will report TabError when KCL has a tab and white space syntax error.

In KCL, it is forbidden to mix tabs and four spaces in one indentation block. And we recommend only using white spaces or tabs for indentation in the entire KCL project, don’t mix them.

For example:

schema Person:
name: str # begin with a tab
age: int # begin with four white spaces,
# and four white spaces != tab in the env

The KCL program will cause the following error message.

error[E1001]: InvalidSyntax
--> File /syntax_error/tab/tab_error_0/main.k:6:5
|
3 | age: int = 1
| ^ inconsistent use of tabs and spaces in indentation
|

Possible resolution:

  • Only use a tab or four white spaces in KCL, do not mix them.

IndentationError

KCL will report IndentationError when KCL has an indentation syntax error.

The KCL syntax includes indentation. A tab or four white spaces in KCL represents an indentation. The other cases will be regarded as syntax errors by KCL.

For example:

schema Person:
name: str # a tab or four white spaces is legal.
age: int # three white spaces are illegal
info: str # two white spaces is illegal

The KCL program will cause the following error message.

error[E1001]: InvalidSyntax
--> /syntax_error/indent/indent_error_0/main.k:3:4
|
3 | age: int # three white spaces are illegal
| ^ unindent 3 does not match any outer indentation level
|

Possible resolution:

  • Only use a tab or four white spaces in the KCL program for indentation.

IllegalArgumentSyntaxError

KCL will report IllegalArgumentSyntaxError when KCL has an illegal argument in KCL syntax.

For example:

# Parameters without default values
# must be in front of parameters with default values.
a = option(type="list", default={"key": "value"}, "key1")

The KCL program will cause the following error message.

error[E1001]: InvalidSyntax
--> /option/type_convert_fail_2/main.k:3:57
|
3 | a = option(type="list", default={"key": "value"}, "key1")
| ^ positional argument follows keyword argument
|

Possible resolution:

func(input_1, ..., input_n, param_with_key_1 = input_with_key_1, ..., param_with_key_n = input_with_key_n)

1.2 KCL Compile Error (E2xxx)

This section mainly includes KCL errors:

ewcodeKCL exceptionmessages
E2F04CannotFindModuleCannot find the module
E2H13UnKnownDecoratorErrorUnKnown decorator
E2C15MixinNamingErrorIllegal mixin naming
E2C16MixinStructureIllegalIllegal mixin structure
E2B17CannotAddMembersErrorCannot add members to a schema
E2B20IndexSignatureErrorInvalid index signature
E2G22TypeErrorThe type got is inconsistent with the type expected
E2L23CompileErrorAn error occurs during compiling
E2L25NameErrorName Error
E2L26ValueErrorValue Error
E2L27KeyErrorKey Error
E2L28UniqueKeyErrorUnique key error
E2A29AttributeErrorAttribute error occurs during compiling
E2D32MultiInheritErrorMultiple inheritance is illegal
E2D34IllegalInheritErrorIllegal inheritance
E2I36IllegalArgumentErrorIllegal argument during compiling
E3L41ImmutableErrorImmutable variable is modified

CannotFindModule (E2F04)

KCL will report CannotFindModule when KCL imports a module that does not exist.

The ewcode of CannotFindModule is E2F04.

For example:

import .some0.pkg1 as some00  # some0 not found in package

Name1 = some00.Name # some0.pkg1.name

The KCL program will cause the following error message.

error[E2F04]: CannotFindModule
--> import_abs_fail_0/app-main/main.k:1:1
|
1 | import .some0.pkg1 as some00 # some0 not found in package
| Cannot find the module .some0.pkg1
|

Possible resolution:

  • Add the import module file under the import path.

UnKnownDecoratorError (E2H13)

KCL will report UnKnownDecoratorError when an unknown decorator is used in KCL.

The ewcode of UnKnownDecoratorError is E2H13.

For example:

@err_deprecated # It is an unknown decorator
schema Person:
firstName: str = "John"
lastName: str
name: str

JohnDoe = Person {
name: "deprecated"
}

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> deprecated/unknown_fail_1/main.k:1:2
|
1 | @err_deprecated # This is a error decorator
| ^ UnKnown decorator err_deprecated
|

Possible resolution:

  • Check whether the decorator exists.

MixinNamingError (E2C15)

KCL will report MixinNamingError when a mixin name does not end with 'Mixin'.

The ewcode of MixinNamingError is E2C15.

For example:

schema Person:
firstName: str
lastName: str
fullName: str

schema Fullname: # It is a mixin, but 'Fullname' is not end with 'Mixin
fullName = "{} {}".format(firstName, lastName)

schema Scholar(Person):
mixin [Fullname]
school: str

JohnDoe = Scholar {
"firstName": "John",
"lastName": "Doe",
"fullName": "Doe Jon"
}

The KCL program will cause the following error message.

error[E2D34]: IllegalInheritError
--> mixin/invalid_name_failure/main.k:10:12
|
10 | mixin [Fullname]
| ^ illegal schema mixin object type 'Fullname'
|

Possible resolution:

  • If the schema is a mixin, then the name of the schema should end with Mixin.

MixinStructureIllegal (E2C16)

KCL will report MixinStructureIllegal when the KCL structure is illegal.

The ewcode of MixinStructureIllegal is E2C16.

Possible resolution:

  • Check the structure of schema as Mixin.

CannotAddMembersError (E2B17)

KCL will report CannotAddMembersError when members that are not in the schema are used.

The ewcode of CannotAddMembersError is E2B17.

For example:

schema Girl:
gender: str = "female"

alice = Girl {
"first": "alice", # "first" can not be found in schema Girl
"last": " Green", # "last" can not be found in schema Girl
"age": 10 # "age" can not be found in schema Girl
}

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> /invalid/add_attribute/main.k:5:5
|
5 | "first": "alice",
| ^ Cannot add member 'first' to schema 'Girl'
|

error[E2L23]: CompileError
--> /invalid/add_attribute/main.k:6:5
|
6 | "last": " Green",
| ^ Cannot add member 'last' to schema 'Girl'
|

error[E2L23]: CompileError
--> /invalid/add_attribute/main.k:7:5
|
7 | "age": 10
| ^ Cannot add member 'age' to schema 'Girl'
|

Possible resolution:

  • Add the members to the schema.
  • Remove the using of the members not exists

IndexSignatureError (E2B20)

The ewcode of IndexSignatureError is E2B20.

KCL will report IndexSignatureError when:

  1. Multiple index signatures in one schema.

For example:

schema Data:
[str]: str
[str]: int # Multiple index signatures in one schema.

data = Data {
name: "test"
}

The KCL program will cause the following error message.

error[E2L23]: CompileError
---> index_signature/fail_1/main.k:3:5
|
3 | [str]: int
| 5 ^ only one index signature is allowed in the schema
|

Possible resolution:

  • Remove the extra index signature in the schema.
  1. The name of index signature attributes has the same name that conflicts with other attributes in the schema.

For example:

schema Data:
name: str # name
[name: str]: str # the same name with the above attribute

data = Data {
name: "test"
}

The KCL program will cause the following error message.

error[E1001]: IndexSignatureError
--> index_signature/fail_2/main.k:3:5
|
3 | [name: str]: str # the same name with the above attribute
| ^ index signature attribute name 'name' cannot have the same name as schema attributes
|

Possible resolution:

  • Remove attributes or index signatures that have conflicts with the same name in the schema, or change their names.
  1. Schema index signature value type has conflicts with the instance of schema.

For example:

schema Data:
[str]: int

data = Data {
name: "test" # Conflict with [str]:int, "test" is a string.
}

The KCL program will cause the following error message.

error[E2G22]: TypeError
--> index_signature/fail_3/main.k:5:5
|
5 | name: "test" # Conflict with [str]:int, "test" is a string.
| ^ expected int, got str(test)
|

Possible resolution:

  • Check that the type of schema index signature is consistent with the attribute type in the schema instance.
  1. Schema index signature has conflicts with schema.

For example:

schema Data:
count: int # got int
[str]: str # except str

data = Data {
count: 1
}

The KCL program will cause the following error message.

error[E1001]: IndexSignatureError
--> index_signature/fail_4/main.k:2:5
|
2 | count: int
| ^ the type 'int' of schema attribute 'count' does not meet the index signature definition [str]: str
|

Possible resolution:

  • Change schema for index signature or change index signature for schema.

TypeError (E2G22)

KCL will report TypeError when a type error occurs in compiling type check.

The ewcode of TypeError is E2G22.

For example:

schema Person:
firstName: str
lastName: int

JohnDoe = Person {
"firstName": "John",
"lastName": "Doe" # Type Error,lastName: int,“Doe” is a string.
}

The KCL program will cause the following error message.

error[E2G22]: TypeError
--> type/type_fail_0/main.k:7:5
|
7 | "lastName": "Doe" # Type Error,lastName: int,“Doe” is a string.
| ^ expected int, got str(Doe)
|

--> type/type_fail_0/main.k:3:5
|
3 | lastName: int
| ^ variable is defined here, its type is int, but got str(Doe)
|

Possible resolution:

  • Check that the type of value assigned to a variable is consistent with the type of the variable.

CompileError (E2L23)

The ewcode of CompileError is E2L23.

KCL will report CompileError when:

  1. unsupport type union.

For example:

_data = [1, 2, 3]
_data |= "value"

The KCL program will cause the following error message.

error[E2G22]: TypeError
--> union/fail/fail_1/main.k:2:1
|
2 | _data |= "value"
| ^ unsupported operand type(s) for |: '[int]' and 'str(value)'
|

Possible resolution:

  1. unsupported operand type.

For example:

a = None
b = 1 + None # Unsupported operand type + for int and None

The KCL program will cause the following error message.

error[E2G22]: TypeError
--> operator/operator_fail_0/main.k:2:5
|
2 | b = 1 + None # Unsupported operand type + for int and None
| ^ unsupported operand type(s) for +: 'int(1)' and 'NoneType'
|

Possible resolution:

  • Adjust the operator so that it supports both operand types.
  • Adjust the operands so that they conform to the constraints of the operator at the same time.
  1. variable is not defined.

For example:

a = 1
b = "${c + 1}" # 'c' is not defined

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> var_not_define_fail_0/main.k:2:8
|
2 | b = "${c + 1}" # 'c' is not defined
| ^ name 'c' is not defined
|

Possible resolution:

  • Define undefined variables.
  • Remove the undefined variable from the expression.
  1. invalid assign expression.

For example:

# pkg.k
a = 1

# main.k
import pkg
pkg.a |= 2

The KCL program will cause the following error message.

error[E2G22]: TypeError
--> pkg_inplace_modify_1/main.k:3:1
|
6 | pkg |= 2
| ^ unsupported operand type(s) for |: 'module 'pkg'' and 'int(2)'
|

Possible resolution:

  • Check the assignment expression.
  1. invalid string expression.

For example:

a = 1
b = "${b = a + 1}" # Invalid string interpolation expression

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> invalid_format_value_fail_0/main.k:2:5
|
2 | b = "${b = a + 1}"
| 5 ^ invalid string interpolation expression 'b = a + 1'
|

Possible resolution:

  • Check the string expression.
  1. invalid loop variable.

For example:

data = {"key1": "value1", "key2": "value2"}
dataLoop = [i for i, j, k in data] # the number of loop variables can only be 1 or 2

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> dict/invalid_loop_var_fail_0/main.k:2:25
|
2 | dataLoop = [i for i, j, k in data] # the number of loop variables can only be 1 or 2
| ^ the number of loop variables is 3, which can only be 1 or 2
|

NameError (E2L25)

KCL will report NameError when a name error occurs in compiling.

The ewcode of NameError is E2L25.

ValueError (E2L26)

KCL will report ValueError will be raised when a value error occurs in compiling.

The ewcode of ValueError is E2L25.

KeyError (E2L27)

KCL will report KeyError will be raised when a key error occurs in compiling.

The ewcode of KeyError is E2L25.

UniqueKeyError (E2L28)

KCL will report UniqueKeyError when duplicate names appear in the KCL code.

The ewcode of UniqueKeyError is E2L28.

For example:

schema Person:
name: str = "kcl"
age: int = 1

schema Person:
aa: int

x0 = Person{}
x1 = Person{age:101}

The KCL program will cause the following error message.

error[E2L28]: UniqueKeyError
--> /schema/same_name/main.k:5:8
|
5 | schema Person:
| ^ Unique key error name 'Person'
|

--> /schema/same_name/main.k:1:8
|
1 | schema Person:
| ^ The variable 'Person' is declared here
|

Possible resolution:

  • Check if the name with error has been used.

AttributeError (E2A29)

KCL will report AttributeError when KCL has an illegal attribute in the schema.

The ewcode of AttributeError is E2A29.

For example:

# pkg
schema A:
field_A: str

# main
import pkg as p

a = p.D + 1

The KCL program will cause the following error message.

error[E2G22]: TypeError
--> /import/module/no_module_attr_fail_0/main.k:4:5
|
4 | a = p.D + 1
| ^ module 'pkg' has no attribute D
|

Possible resolution:

  • Check for the existence of the schema attribute when using it.

MultiInheritError (E2D32)

KCL will report MultiInheritError when multiple inheritance appears in the schema.

The ewcode of MultiInheritError is E2D32.

For example:

schema Person:
firstName: str
lastName: str

schema KnowledgeMixin:
firstName: int
subject: str

schema Scholar(KnowledgeMixin, Person):
school: str

The KCL program will cause the following error message.

error[E1001]: InvalidSyntax
--> /schema/inherit/multi_inherit_fail_1/main.k:9:30
|
9 | schema Scholar(KnowledgeMixin, Person):
| ^ expected one of [")"] got ,
|

Possible resolution:

  • Check the inheritance structure of the program, and multi-inheritance is not supported in KCL.

IllegalInheritError (E2D34)

KCL will report IllegalInheritError when an illegal inheritance occurs in the schema.

The ewcode of IllegalInheritError is E2D34.

For example:

schema FullnameMixin:
fullName = "{} {}".format(firstName, lastName)

schema Scholar(FullnameMixin): # mixin inheritance is illegal
school: str

The KCL program will cause the following error message.

error[E2D34]: IllegalInheritError
--> /schema/inherit/inherit_mixin_fail/main.k:4:16
|
4 | schema Scholar(FullnameMixin):
| ^ invalid schema inherit object type, expect schema, got 'FullnameMixin'
|

Possible resolution:

  • Schema supports single inheritance of schema in KCL.

IllegalArgumentError (E2I36)

KCL will report IllegalArgumentError when the argument of option in KCL is illegal.

The ewcode of IllegalArgumentError is E2I36.

For example:

a = option("key")

# kcl main.k -D key=value=
# key=value= is an illegal expression

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
Invalid value for top level arguments

Possible resolution:

  • Check whether the KCL option arguments are legal.

ImmutableError (E3L41)

KCL will report ImmutableError when the value of the immutable variable changes.

The ewcode of ImmutableError is E3L41.

For example:

a = 2147483646
a += 1

The KCL program will cause the following error message.

error[E1001]: ImmutableError
--> augment_assign/main.k:2:1
|
2 | a += 1
| ^ Immutable variable 'a' is modified during compiling
|

--> augment_assign/main.k:1:1
|
1 | a = 2147483646
| ^ The variable 'a' is declared here firstly
|
note: change the variable name to '_a' to make it mutable

Possible resolution:

  • Set immutable variables changed to private or remove immutable variables.

1.3 KCL Runtime Error (E3xxx)

This section mainly includes KCL errors:

ewcodeKCL exceptionmessages
E3F06RecursiveLoadRecursively loading module
E3K04FloatOverflowFloat overflow
E3K09IntOverflowInteger overflow
E3N11DeprecatedErrorDeprecated error
E3A30AttributeRuntimeErrorAttribute error occurs at runtime
E3G21TypeRuntimeErrorThe type got is inconsistent with the type expected
E3B17SchemaCheckFailureSchema check is failed to check condition
E3B19CannotAddMembersRuntimeErrorCannot add members to a schema
E3M38EvaluationErrorEvaluation failure
E3M39InvalidFormatSpecInvalid format specification
E3M40AssertionErrorAssertion failure
E3M42RecursionErrorRecursively reference

RecursiveLoad (E3F06)

KCL will report RecursiveLoad when a cycle import of external packages occurs in KCL.

The ewcode of RecursiveLoad is E2F06.

For example:

# module.k
import main # module.k imports main.k

print('module')

# main.k
import module # main.k imports module.k

print('main')

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> /import/recursive_import_fail/main.k:4
|
2 | import module # main.k imports module.k
| ^ There is a circular import reference between module main and module
|

Possible resolution:

  • Check whether there is a circle import in KCL.

FloatOverflow (E3K04)

KCL will report FloatOverflow when a floating-point number overflows in KCL.

The ewcode of FloatOverflow is E3K04.

For example:

uplimit = 3.402823466e+39
epsilon = 2.220446049250313e-16
a = uplimit * (1 + epsilon)

# kcl main.k -r -d

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /range_check_float/overflow/number_0/main.k:3:1
|
3 | a = uplimit * (1 + epsilon)
| 3.4028234660000003e+39: A 32-bit floating point number overflow
|

Possible resolution:

  • Check whether the value of the float is the float range supported by KCL.

IntOverflow (E3K09)

KCL will report IntOverflow when an integer number overflows in KCL.

The ewcode of IntOverflow is E3K09.

For example:

_a = 9223372036854775807
_a += 1

# kcl test.k -d

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /range_check_int/augment_assign_fail_1/main.k:2:1
|
2 | _a += 1
| 9223372036854775808: A 64 bit integer overflow
|

Possible resolution:

  • Check whether the value of the integer is the integer range supported by KCL.

DeprecatedError (E3N11)

KCL will report DeprecatedError when a deprecated variable is used and the strict is True.

The ewcode of DeprecatedError is E3N11.

For example:

schema Person:
firstName: str = "John"
lastName: str
@deprecated(version="1.16", reason="use firstName and lastName instead", strict=True)
name: str

JohnDoe = Person {
name: "deprecated" # name is deprecated and strict is True
}

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /range_check_float/overflow/number_0/main.k:7:1
|
7 | JohnDoe = Person {
| name was deprecated since version 1.16, use firstName and lastName instead
|

Possible resolution:

  • When strict is set to True, using deprecated code will cause an error and stop KCL.
  • You can set the strict to False which will cause a warning insteads of an error.
  • Adjust the code without using deprecated code.

AttributeRuntimeError (E3A30)

KCL will report AttributeRuntimeError, if an error occurs during dynamically accessing schema attributes through variables at runtime.

The ewcode of AttributeRuntimeError is E3A30.

For example:

import math

a = math.err_func(1) # err_func is not found in math

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /import/module/no_module_attr_fail_2/main.k:3:5
|
3 | a = math.err_func(1) # err_func is not found in math
| ^ module 'math' has no attribute err_func
|

Possible resolution:

  • Check whether the attributes of schema are correct.

TypeRuntimeError (E3G21)

KCL will report TypeRuntimeError when an type error occurs in the runtime type check.

The ewcode of TypeRuntimeError is E3G21.

For example:

schema Person:
name: str = "Alice"

_personA = Person {}
_personA |= {"name" = 123.0} # name: str = "Alice"
personA = _personA

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /fail/fail_4/main.k:2:1
|
2 | name: str = "Alice"
| expect str, got float
|

Possible resolution:

  • Stop the wrong type union or adjust to the type union supported by KCL.

SchemaCheckFailure (E3B17)

KCL will report SchemaCheckFailure when the schema check conditions are not met.

The ewcode of SchemaCheckFailure is E3B17.

For example:

schema Person:
lastName: str
age: int
check:
age < 140, "age is too large"

JohnDoe = Person {
"lastName": "Doe",
"age": 1000 # the check condition: age < 140
}

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /check_block/check_block_fail_1/main.k:7:11
|
7 | JohnDoe = Person {
| ^ Instance check failed
|

--> /check_block/check_block_fail_1/main.k:5:1
|
5 | age < 140, "age is too large"
| Check failed on the condition
|

Possible resolution:

  • Check whether the attributes of schema can satisfy the conditions in check.

CannotAddMembersRuntimeError (E3B19)

KCL will report CannotAddMembersRuntimeError when members that are not in the schema are used.

The ewcode of CannotAddMembersRuntimeError is E3B19.

For example:

schema Name:
name: str

schema Person:
name: Name

person = Person {
name.err_name: "Alice" # err_name is not found in schema Name
}

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> /nest_var/nest_var_fail_1/main.k:8:5
|
8 | name.err_name: "Alice" # err_name is not found in schema Name
| ^ Cannot add member 'err_name' to schema 'Name'
|

Possible resolution:

  • Add a non-existent member to the schema.
  • Access members that exist in the schema.

EvaluationError (E3M38)

KCL will report EvaluationError when an illegal evaluation occurs in KCL.

The ewcode of EvaluationError is E3M38.

For example:

_list1 = [1, 2, 3] # _list1 is a variable, and its type can only be known at runtime
_list2 = None # _list1 is a variable, and its type can only be known at runtime

result2 = _list1 + _list2 # list + NoneType is illegal

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /datatype/list/add_None_fail/main.k:1
|
4 | result2 = _list1 + _list2 # list + NoneType is illegal
| can only concatenate list (not "NoneType") to list
|

Possible resolution:

  • Check whether the evaluation of the expression is legal.

InvalidFormatSpec (E3M39)

KCL will report InvalidFormatSpec when an illegal string format appears in KCL.

The ewcode of InvalidFormatSpec is E3M39.

For example:

a = 1
b = 1
data = "${a: #js}" + " $$ " # #js is illegal string

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> /datatype/str_interpolation/invalid_format_spec_fail_0/main.k:3
|
3 | data = "${a: #js}" + " $$ " # #js is illegal string
| ^ #js is a invalid format spec
|

Possible resolution:

  • Adjust illegal String to String supported by KCL standards.

AssertionError (E3M40)

KCL will report AssertionError when assert False occurs in KCL.

The ewcode of AssertionError is E3M40.

For example:

assert False

The KCL program will cause the following error message.

error[E3M38]: EvaluationError
--> /assert/invalid/fail_0/main.k:1
|
1 | assert False
|
|

Possible resolution:

  • Check the condition of Assert, and when the Assert condition is False, such an error occurs, removing the Assert statement or changing the condition to True.

CycleInheritError (E2D33)

KCL will report CycleInheritError when circle inheritance appeared in the schema.

The ewcode of CycleInheritError is E2D33.

For example:

schema Parent(Son):
parent_field: str

schema Son(GrandSon):
son_field: str

schema GrandSon(Parent):
grandson_field: str

parent = Parent {
parent_field: ""
}

The KCL program will cause the following error message.

error[E2L23]: CompileError
--> /inherit/cycle_inherit_fail_1/main.k:7:8
|
7 | schema GrandSon(Parent):
| ^ There is a circular reference between schema GrandSon and Parent
|

Possible resolution:

  • Check schema inheritance relationship to avoid A inheritance B and B inheritance A at the same time.

RecursionError (E3M42)

KCL will report RecursionError when a circle reference appears in the program.

The ewcode of RecursionError is E3M42.

For example:

schema Parent(Son):
parent_field: str
son: Son = Son { # Parent has attribute Son
parent: Parent {
parent_field: "123"
}
}

schema Son:
son_field: str
parent: Parent = Parent { # Son has attribute Parent
son: Son {
son_field: "123"
}
}

parent = Parent {
parent_field: "",
}

The KCL program will cause the following error message.

thread 'main' has overflowed its stack
fatal runtime error: stack overflow

Possible resolution:

  • Check the members in the schema to avoid the problem of circle references.

1.4 KCL Compile Warning (W2xxx)

This section mainly includes KCL warnings:

ewcodeKCL exceptionmessages
W2K04FloatUnderflowFloat underflow
W2P10InvalidDocstringInvalid docstring
W2N12DeprecatedWarningDeprecated warning

FloatUnderflow (W2K04)

KCL will report FloatUnderflow when a floating-point number underflows in KCL.

The ewcode of FloatUnderflow is W2K08.

Possible resolution:

  • Check whether the value of the float number is in the range supported by KCL.

InvalidDocstring (W2P10)

KCL will report InvalidDocstring when a string is illegal in KCL doc.

The ewcode of InvalidDocstring is W2P10.

Possible resolution:

  • Please write doc according to KCL standards.

DeprecatedWarning (W2N12)

KCL will report DeprecatedWarning when a deprecated variable is used and the strict is False.

The ewcode of DeprecatedWarning is W2N12.

Possible resolution:

  • Try not to use deprecated code. If the strict is True, KCL will output the error and stop running.