NodeTriggersOkRead is a case of a node creating a rich bool effect for map reads, channel receives, and user-defined functions in the "ok" form. Specifically, it matches on `AssignStmt`s of the form - `v, ok := mp[k]` - `v, ok := <-ch` - `r0, r1, r2, ..., ok := f()`
(rootNode *RootAssertionNode, nonceGenerator *guard.NonceGenerator, node ast.Node)
| 288 | // - `v, ok := <-ch` |
| 289 | // - `r0, r1, r2, ..., ok := f()` |
| 290 | func NodeTriggersOkRead(rootNode *RootAssertionNode, nonceGenerator *guard.NonceGenerator, node ast.Node) ([]RichCheckEffect, bool) { |
| 291 | lhs, rhs := asthelper.ExtractLHSRHS(node) |
| 292 | if len(lhs) < 2 || len(rhs) != 1 { |
| 293 | return nil, false |
| 294 | } |
| 295 | |
| 296 | okExpr := lhs[len(lhs)-1] |
| 297 | lhsOkParsed := parseExpr(rootNode, okExpr) |
| 298 | if lhsOkParsed == nil { |
| 299 | // here, the lhs `ok` operand is not trackable so there are no rich effects |
| 300 | return nil, false |
| 301 | } |
| 302 | |
| 303 | var effects []RichCheckEffect |
| 304 | |
| 305 | switch rhs := rhs[0].(type) { |
| 306 | case *ast.IndexExpr: |
| 307 | // this is the case of `v, ok := mp[k]`. Early return if the lhs is not a map read of the expected format |
| 308 | if len(lhs) != 2 { |
| 309 | return nil, false |
| 310 | } |
| 311 | |
| 312 | rhsXType := rootNode.Pass().TypesInfo.Types[rhs.X].Type |
| 313 | if typeshelper.IsDeeplyType[*types.Map](rhsXType) { |
| 314 | // Create a rich check effect for `v` part of the map read in `v, ok := mp[k]` |
| 315 | if lhsValueParsed := parseExpr(rootNode, lhs[0]); lhsValueParsed != nil { |
| 316 | // Here, the lhs `value` operand is trackable |
| 317 | effects = append(effects, &MapOkRead{ |
| 318 | okRead{ |
| 319 | root: rootNode, |
| 320 | value: lhsValueParsed, |
| 321 | ok: lhsOkParsed, |
| 322 | guard: nonceGenerator.Next(lhs[0]), |
| 323 | }}) |
| 324 | } |
| 325 | |
| 326 | // Create a rich check effect for the map read `mp[k]` part of `v, ok := mp[k]`. This is important |
| 327 | // to support cases when consequent map reads are used instead of creating a local variable `v`. For example, |
| 328 | // ``` |
| 329 | // if _, ok := mp[k]; ok { |
| 330 | // return *mp[k] |
| 331 | // } |
| 332 | // ``` |
| 333 | if rhsParsed := parseExpr(rootNode, rhs); rhsParsed != nil { |
| 334 | // Here, the rhs `map read` itself is trackable |
| 335 | effects = append(effects, &MapOkRead{ |
| 336 | okRead{ |
| 337 | root: rootNode, |
| 338 | value: rhsParsed, |
| 339 | ok: lhsOkParsed, |
| 340 | guard: nonceGenerator.Next(rhs), |
| 341 | }}) |
| 342 | } |
| 343 | |
| 344 | // Create a rich check effect for the map itself, `mp`, in `v, ok := mp[k]` |
| 345 | if rhsMapParsed := parseExpr(rootNode, rhs.X); rhsMapParsed != nil { |
| 346 | // Here, the rhs `map` operand is trackable |
| 347 | effects = append(effects, &MapOkReadRefl{ |
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