SQF Private Variable Checker
Finds local variables in .sqf files that are assigned without ever being declared
private. In SQF an undeclared _variable leaks into the caller's scope, which is a
classic source of hard-to-trace bugs in Arma mission and mod code.
params ["_unit"];
private _position = getPosATL _unit; // fine
_speed = speed _unit; // warning: assigned without being declared private
Features
- Live diagnostics — squiggles appear in
.sqf files as you type, with the results
in the Problems panel.
- Recursive workspace scan —
SQF: Check Workspace for Non-Private Local Variables
walks every .sqf file in the workspace, reports progress, and writes a per-file
summary to the SQF Private Variable Checker output channel.
- Quick fix —
Declare '_myVariable' private inserts the missing keyword; a second action
fixes every occurrence in the file at once.
- Cross-file duplicate-name check — if a non-private variable's name is also used
as a local variable in a different
.sqf file in the workspace, it is reported
separately and more severely than a plain missing-private warning, since the
non-private one can silently read or overwrite the other file's variable if the two
ever end up sharing a scope (for example one script calls or inlines the other).
Two local variables sharing a name within the same file are not affected — normal
SQF scoping already covers that case.
- High risk detection — if a non-private variable's name has more than one
non-private occurrence across the workspace (i.e. two or more files, not just one,
all forgot
private for the same name), it is reported even more severely than a
plain duplicate-name collision: none of those occurrences has private scope protecting
it. Its own ultraHighRiskSeverity setting controls how severe that is (error by default).
- Severity filtering —
minimumSeverity hides diagnostics below a chosen severity,
in both the Problems panel and workspace scan summaries. For example, set it to
warning to see warnings and errors but hide information/hint entries, or to error
to see errors only.
What counts as a declaration
| Form |
Treated as private |
private _x = 1; |
yes |
private ["_x", "_y"]; |
yes |
params ["_x", ["_y", 0]]; |
yes (treatParamsAsPrivate) |
for "_i" from 0 to 10 do {…} |
yes (treatForLoopVariablesAsPrivate) |
_this, _x, _forEachIndex, _exception, _thisScript, … |
never reported |
A declaration in an outer scope covers inner {…} blocks, but not the other way round.
Variable names are compared case-insensitively, the way the engine does it. Comments,
string literals and preprocessor lines (#define, #include) are skipped, so macro
bodies do not produce false positives.
Commands
| Command |
Description |
SQF: Check Workspace for Non-Private Local Variables |
Recursive scan of the whole workspace |
SQF: Check Current File for Non-Private Local Variables |
Re-check the active editor |
SQF: Clear Non-Private Local Variable Diagnostics |
Empty the Problems panel |
Settings
| Setting |
Default |
Description |
sqfPrivateVariableChecker.enable |
true |
Turn the checker off entirely |
sqfPrivateVariableChecker.include |
**/*.sqf |
Files included in a workspace scan |
sqfPrivateVariableChecker.exclude |
["**/node_modules/**", "**/.git/**"] |
Files excluded from a workspace scan |
sqfPrivateVariableChecker.severity |
warning |
error, warning, information or hint |
sqfPrivateVariableChecker.flagDuplicateLocalNames |
true |
Cross-check non-private variables against every other .sqf file in the workspace |
sqfPrivateVariableChecker.duplicateNameSeverity |
error |
Severity for a non-private variable whose name is also used in another file |
sqfPrivateVariableChecker.ultraHighRiskSeverity |
error |
Severity for a non-private variable whose name is missing private in two or more different files |
sqfPrivateVariableChecker.minimumSeverity |
hint |
Hide diagnostics below this severity, e.g. warning for warnings + errors, or error for errors only |
sqfPrivateVariableChecker.checkOnType |
true |
Re-check while typing, otherwise only on open and save |
sqfPrivateVariableChecker.treatParamsAsPrivate |
true |
Accept params [...] as a declaration |
sqfPrivateVariableChecker.treatForLoopVariablesAsPrivate |
true |
Accept for "_i" as a declaration |
sqfPrivateVariableChecker.magicVariables |
[] |
Extra engine- or macro-supplied names to ignore |
Development
npm install
npm run watch # esbuild + tsc in watch mode
npm test # unit tests plus integration tests in a real VS Code instance
Press F5 to launch the Extension Development Host, then open examples/sample.sqf,
examples/sample2.sqf and examples/sample3.sqf to see the checker at work,
including the duplicate-name case (_index, missing private in one file only) and
the ultra-high-risk case (_speed, missing private in two files at once).
Source layout:
src/analyzer/tokenizer.ts — SQF tokenizer (comments, strings, preprocessor)src/analyzer/analyzer.ts — per-file scope tracking and the missing-private rule,
free of VS Code APIssrc/workspaceIndex.ts — tracks which local variable names each scanned file uses,
and which of those are missing private there, to power the cross-file
duplicate-name and ultra-high-risk checks; also free of VS Code APIssrc/diagnostics.ts — runs the analyzer per file, keeps the workspace index up to
date, and turns the results into diagnostics for open documents and files on disksrc/quickFix.ts — the private insertion code actionssrc/extension.ts — activation, commands, document listeners
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