SCR201: unknown-system-function

system.* member that does not exist in Ignition 8.3

Code	SCR201
Name	unknown-system-function
Category	Scripts (SCR)
Default severity	error
Enabled by default	yes
Fix available	no
ign-lint equivalent	none

What it does

Reports system.x.y (and the legacy alias fpmi.x.y) where y is not a function, constant, object or package of the package system.x in any scope of Ignition 8.3 (gateway, Vision Client or Designer). Aliases are followed: after db = system.db, db.runQery(...) is checked as system.db.runQery. The chain is checked up to the first member that is not a package: what follows a function, constant or object (system.net.httpClient().get) is not checked. A local variable named system that is not an alias of the scripting API is not checked.

The member list comes from the scripting API of a real 8.3 gateway with Ignition's standard modules. Third-party modules add their own top-level packages (for example a MES module's system.mes) and sometimes add functions to Ignition's own packages, so by default a name is only reported when it is a near miss of a known member of the same package: the same name in other letter case, one edit away for names of four or more letters, or two edits away for names of eight or more (system.tag.readBlockng, system.Tag, system.datset). The message names the member it probably means. In strict mode every unknown member of a known package is reported; list the members your modules add in allow.

Why is this bad?

The script raises AttributeError when it reaches the name: usually a typo or a function that only existed in an older Ignition version.

Example

def runAction(self, event):
    values = system.tag.readBlockng(["[default]Line/Speed"])

Use instead:

def runAction(self, event):
    values = system.tag.readBlocking(["[default]Line/Speed"])

Options

• allow (default []): extra system.* paths that exist on your gateways (from third-party or in-house modules). * matches any characters, ? one character, and a path also allows everything below it, for example ["system.mes", "system.util.myCompanyHelper"]. Listing a path here only silences this rule: a system.* member that Ignition 8.3 does not have may run code or read files, so it still keeps the safe fixes of other rules from being safe until the project lists it under [fix] vetted-system-functions.

Option reference

Set in [rules.SCR201] of iglint.toml (or [tool.iglint.rules.SCR201] in pyproject.toml).

Option	Type	Default	Description
allow	array of strings	[]	Extra system.* paths (wildcards *, ?) that exist on your gateways.

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Generated from the rule metadata by iglint generate-docs; iglint rule SCR201 prints the same page in the terminal. Source: docs/rules/SCR201.md.