Elamur Groupantswasi-path-open
The groupant beside wasi-host/src/lib.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial | approximant |
| ast | partial | ../syntax.json |
| cost | symbolic source derived | invariant |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | executed bounded checks | tests |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
behavior_complement | behavior_complement | partial source derived model | behavior_complement |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
creation_precedence | creation_precedence | partial source derived model | creation_precedence |
late_failure | late_failure | partial source derived model | late_failure |
directory_rights | directory_rights | partial source derived model | directory_rights |
time_flags | time_flags | partial source derived model | time_flags |
Model text
descriptant
wasi-path-open
path_open resolves follow||creat, then symlink/EXCL/missing checks, optional create, kind/access/truncate, journals Open, allocates descriptor and stores fd. set_times prioritizes NOW bit8 over explicit bit4, otherwise stat only.
Epoch 2026-10-31
Prospective review recorded before edits. Source review found late output FAULT effects and weaker-than-capability rights metadata; these are modeled as current behavior rather than silently repaired. Only bounded new test blocks were added; production code remains unchanged. Actual finite results and exact restoration receipts live under $MOVA_DATA/runs/octopus-wave31-wasi-2026-10-31. No full mlab guest, frozen suite, GPU or corpus run. This node retains its scoped observations for future refinement.
approximant
Forward relation
path_open resolves follow||creat, then symlink/EXCL/missing checks, optional create, kind/access/truncate, journals Open, allocates descriptor and stores fd. set_times prioritizes NOW bit8 over explicit bit4, otherwise stat only.
Scope: wasi-path-open. State and transitions follow the authoritative source, including partial effects before errors. No executable approximate replacement is attached: categorical errno/effects and module execution lack a useful validated percentage metric; future numerical profiles may only use1/2/5/10% caps after domain/reference evidence.
invariant
Invariant and cost
path_open resolves follow||creat, then symlink/EXCL/missing checks, optional create, kind/access/truncate, journals Open, allocates descriptor and stores fd. set_times prioritizes NOW bit8 over explicit bit4, otherwise stat only.
The invariant is conditional on the admitted transition: Missing file without creat cannot produce a successful descriptor; directory requested as writable cannot open successfully. Allocation failure does not exclude earlier creation.
Cost: Path resolution and Vfs costs plus O(F) allocation and O(path bytes) copies; truncate/create effects precede final pointer validation.
No wall-time gain, universal resource bound or atomic rollback is inferred. External Vfs/wasmi/native-mlab work remains separately charged.
models
Typed model catalog
behavior_complement
Subject: wasi-host/src/lib.rs at SHA-256 91213ce9038107912c2dd707c3a6639a2d723cdfceb02981a166a6853800248e, scope wasi-path-open. Domain: the source transition and bounded fixtures described in approximant.md; readable valid host resources where required. Observation: returned values, byte coordinates, state/effect order, not total-system semantics. Operator/relation: Missing file without creat cannot produce a successful descriptor; directory requested as writable cannot open successfully. Allocation failure does not exclude earlier creation.
Status: partial source-derived relation; complement is a scoped exclusion hypothesis, reverse preserves all compatible antecedents described rather than a chosen inverse. Assumptions: production branch order, declared coordinate/resource premises; no completeness claim for untested inputs. Evidence: tests.md distinguishes actual execution from source review; finite observations can falsify but not prove the relation.
reverse_reconstruction
Subject: wasi-host/src/lib.rs at SHA-256 91213ce9038107912c2dd707c3a6639a2d723cdfceb02981a166a6853800248e, scope wasi-path-open. Domain: the source transition and bounded fixtures described in approximant.md; readable valid host resources where required. Observation: returned values, byte coordinates, state/effect order, not total-system semantics. Operator/relation: Opened fd and canonical path constrain a resolved predecessor but do not recover original symlink spelling, prior contents after truncation, or file creation history.
Status: partial source-derived relation; complement is a scoped exclusion hypothesis, reverse preserves all compatible antecedents described rather than a chosen inverse. Assumptions: production branch order, declared coordinate/resource premises; no completeness claim for untested inputs. Evidence: tests.md distinguishes actual execution from source review; finite observations can falsify but not prove the relation.
creation_precedence
Subject: wasi-host/src/lib.rs at SHA-256 91213ce9038107912c2dd707c3a6639a2d723cdfceb02981a166a6853800248e, scope wasi-path-open. Domain: the source transition and bounded fixtures described in approximant.md; readable valid host resources where required. Observation: returned values, byte coordinates, state/effect order, not total-system semantics. Operator/relation: Existing symlink without resolution returns LOOP before EXCL; absent without creat NOENT, absent+directory INVAL.
Status: partial source-derived relation; complement is a scoped exclusion hypothesis, reverse preserves all compatible antecedents described rather than a chosen inverse. Assumptions: production branch order, declared coordinate/resource premises; no completeness claim for untested inputs. Evidence: tests.md distinguishes actual execution from source review; finite observations can falsify but not prove the relation.
late_failure
Subject: wasi-host/src/lib.rs at SHA-256 91213ce9038107912c2dd707c3a6639a2d723cdfceb02981a166a6853800248e, scope wasi-path-open. Domain: the source transition and bounded fixtures described in approximant.md; readable valid host resources where required. Observation: returned values, byte coordinates, state/effect order, not total-system semantics. Operator/relation: MFILE or out FAULT can follow creation/truncation; Open journal result reflects pre-allocation path operation.
Status: partial source-derived relation; complement is a scoped exclusion hypothesis, reverse preserves all compatible antecedents described rather than a chosen inverse. Assumptions: production branch order, declared coordinate/resource premises; no completeness claim for untested inputs. Evidence: tests.md distinguishes actual execution from source review; finite observations can falsify but not prove the relation.
directory_rights
Subject: wasi-host/src/lib.rs at SHA-256 91213ce9038107912c2dd707c3a6639a2d723cdfceb02981a166a6853800248e, scope wasi-path-open. Domain: the source transition and bounded fixtures described in approximant.md; readable valid host resources where required. Observation: returned values, byte coordinates, state/effect order, not total-system semantics. Operator/relation: Directory opened with write requested returns ISDIR; file with directory flag returns NOTDIR.
Status: partial source-derived relation; complement is a scoped exclusion hypothesis, reverse preserves all compatible antecedents described rather than a chosen inverse. Assumptions: production branch order, declared coordinate/resource premises; no completeness claim for untested inputs. Evidence: tests.md distinguishes actual execution from source review; finite observations can falsify but not prove the relation.
time_flags
Subject: wasi-host/src/lib.rs at SHA-256 91213ce9038107912c2dd707c3a6639a2d723cdfceb02981a166a6853800248e, scope wasi-path-open. Domain: the source transition and bounded fixtures described in approximant.md; readable valid host resources where required. Observation: returned values, byte coordinates, state/effect order, not total-system semantics. Operator/relation: NOW wins when both bits8/4 set; atime ignored by helper. Missing path still fails through stat when neither bit set.
Status: partial source-derived relation; complement is a scoped exclusion hypothesis, reverse preserves all compatible antecedents described rather than a chosen inverse. Assumptions: production branch order, declared coordinate/resource premises; no completeness claim for untested inputs. Evidence: tests.md distinguishes actual execution from source review; finite observations can falsify but not prove the relation.
tests
Checks and limits
Named actual-source tests run twice per debug/release; exact commands and numeric statuses retained externally. Test success is finite evidence only.
Exact names: tests::open_read_seek_write, tests::escape_and_absolute_paths_are_not_capable, tests::wave31_late_faults_keep_prior_effects.
Memory tests bypass linker ABI; tiny empty/unreachable guests exercise engine outcomes only. The CLI test uses isolated import/export/journal fixtures.
Five compiled production/helper-source controls: append offset, virtual clock advance, trap status, CLI export gate and newest-mtime max. Each compiles, fails its selected assertion, restores exact original bytes and passes again. These controls cover their target relations, not every node. No assertion-only mutants. See external source-test-map.json, native-commands.json, verify.rs and numeric/raw receipts in $MOVA_DATA/runs/octopus-wave31-wasi-2026-10-31. The example main and frozen mlab paths are never executed.
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