ARCADIA-Studio/harness/process-group-removal-evidence-20260925/source-oracle-investigation.md

Process removal source-oracle investigation — 2026-09-25

Local-only, bounded investigation at source fe637dcd277b17653139ffa234e601b29775c565. Parent owns Process removal and oracle integration. No production code, tests, or versioned fixtures edited; no Cargo, build, UI or Gitea operation. Another worker's model_menu.rs edit was observed and left untouched.

Conclusion

The full semantic Project comparison passed before the lexical assertion failed. The three selected/dependent declarations (Action a, Control c, SequenceLink approved) are removed, Process steps retain e1,e2, reused definitions and unrelated OA/SA records agree with the independently authored model oracle. The failed assertion is an incorrect lossless-source oracle, not evidence of a semantic deletion defect or a newly introduced writer regression.

The source contract explicitly says removed declarations erase syntax tokens while retaining their comments and whitespace as enclosing annotations (docs/language.rst:1987-1989). It also requires deletion annotations be separated from adjacent declarations with blank lines (:1963-1964) and preserves surviving reference-list chunks and their separator-adjacent trivia (:1993-2000). Canonical export is a different operation (:1926-1929); the mutation path must not silently reformat source (:1969-1973). harness/release-source-project.md:43-45 and harness/DECISIONS.md:87,93 corroborate this accepted policy.

This does not establish that blank space-only annotations are the ideal future editor UX. They follow an explicit existing contract and pre-existing implementation; changing them would require a separately scoped source-policy decision and source/core validation. Silently removing them solely to satisfy a newly authored Process oracle would change the common writer contract. No production formatting fix is justified within this aggregate-removal acceptance task.

Independent derivation

Input harness/fixtures/process-removal-baseline-20260925.arcadia:

• Source commit: fe637dcd277b17653139ffa234e601b29775c565.
• Git blob: 9570e150d160bea87dc70b5dacedc692eb3708b4.
• SHA-256: 9965f4024584d64ac81442724aeb77b018b0cfae94e50bd412c5dcbbac49f6bf.
• Original UTF-8/LF bytes are required; derivation refuses changed input or CR characters.

1. Original steps are [@a,@e1,@c,@e2]. Surviving entries have no leading/trailing trivia and the removed entries have no trivia. Retain @e1 and @e2, emit their one comma, and invent no whitespace: [@e1,@e2]. source_project.rs:1516-1651 implements unique-reference identity matching and chunk preservation; this is not canonical , formatting.
2. For each removed single-line declaration, quoted strings are indivisible syntax tokens. Their interior spaces disappear with those strings. Every whitespace byte outside strings survives, including the four-space indentation. Independent token-boundary counting yields 22 spaces for Action a, 20 for Control c, 16 for link approved.
3. source_structure.rs:236-271 creates deleted-declaration pieces through trivia; source_project.rs:1127-1139 retains only Whitespace/Comment tokens. attached_span at source_structure.rs:435 includes the line indentation and leaves the ordinary following newline in the enclosing gap when there is no trailing comment.
4. Existing concrete structural policy (source_structure.rs:397-404) surrounds each orphaned annotation with two LF characters on each side. The untouched original gap has one LF on either side. Consequently the exact post-predecessor sequence is "\n\n\n" + " " * N + "\n\n\n", followed by the next declaration's unchanged four-space indentation. These are three LF characters per side, not three full empty lines per side.
5. All other baseline bytes remain unchanged. The specification requires whitespace retention and blank-line separation; the exact two-LF inserted boundary is the established writer policy, not a claim that every conforming future writer must always choose that count.

The common structural file's latest historical change is 4e8575bd1127d132b8170b408163ef234b4d307e (feat: preserve nested source projects across desktop and REST), predating this Process change. Existing tests crates/oa-core/tests/source_project.rs:1065 (removed_list_items_and_declarations_keep_comments_as_enclosing_annotations) and crates/oa-core/tests/source_nested_updates.rs:187 (deleting_owner_retains_annotations_and_extracts_independently_moved_descendant) verify comment retention, semantic equality and annotation ownership. Those tests support the policy but do not themselves prescribe the exact 22/20/16 whitespace-only output; the above input-specific derivation does.

Created artifacts and separate observation check

• .local/process-removal-native/derive-source-oracle-v2.ps1: create-only fixture-specific derivation script. It reads only the checksum-pinned baseline, applies the independently stated lexical rules, and refuses to overwrite an existing output. It does not read production writer code, expected-v1, failure logs or actual output. Script SHA-256: 38979a4b233b7d28a6392070c72298fb6c17660b2a2c8dc2a3bff74c3c816fae.
• .local/process-removal-native/expected-removed-v2.arcadia: independently derived candidate, 2258 bytes, SHA-256 b4a2b07ad4c796f555c61945ca42b1c221b454b35488c60fefc86f96f7aa71ba.
• Reproduce into a new destination: & .local/process-removal-native/derive-source-oracle-v2.ps1 -OutputPath <new-output.arcadia>. The script refuses changed baseline and an existing destination.

Only after creating the candidate, I separately extracted the sole left: SourceBundle project's JSON-compatible ASCII debug string from the failed log using an anchored shape check and ConvertFrom-Json, then encoded UTF-8 and compared byte-for-byte. MATCH, 2258 derived bytes and 2258 observed bytes. This observation corroborates the rule derivation; actual output was not an input to the derivation script. Failure log .local/scenario-group-gates/process-removal-tests-1/stdout.log SHA-256: aeb571241a21c246ac94ae64f698b478ded69988b9f811c806bb689bb8af6dc9.

The original versioned expected-v1 remains untouched (SHA-256 117b550f0c10753f53febb3ca6beb2c8088688ffa707f21eac654573e4a3d29c). The original failed run remains a failure. No new test execution or native acceptance is claimed.

Concrete next action

Parent should preserve v1/failure evidence, introduce a new versioned v2 literal fixture from the pinned independent candidate, and point the full-source comparison and separately versioned native oracle/manifest to v2. Keep the full Project comparison, exact-source assertion and Undo/Redo checks. Explain the lexical correction and explicitly preserve significant space-only lines against editor trimming; a narrowly scoped Git whitespace attribute may be needed for the fixture, consistent with other exact source oracles. Re-run the relevant failed gate on the identified new source and separately review the menu correction. Do not canonicalize the baseline or weaken exact-source equality to semantic-only equality.