Module structure 

Structural and destructive spreadsheet edits via spreadsheets.batchUpdate.

The drive sheets add-sheet/rename-sheet/insert-rows/insert-columns (additive, issue #1613, ADR-0075), insert-range (additive, issue #1838), duplicate-sheet/reorder-sheet/hide-sheet/show-sheet (also additive, issue #1643, ADR-0078), move-rows/move-columns (also additive — nothing is discarded, issue #1834, ADR-0083), delete-sheet/delete-rows/delete-columns/delete-range (destructive, issue #1623, ADR-0077), and update-workbook-properties (also additive, issue #1836, ADR-0086) engines, gated by the ADR-0071 folder write-permission rules.

update-workbook-properties is the one verb here with no sheet target: every other verb acts on a tab within the workbook, this one acts on the workbook itself (locale, time zone, auto-recalc, iterative calculation — deliberately not spreadsheetTheme, a large nested type left for a future issue). StructureVerb::sheet_title returns Option<&str> rather than &str for exactly this reason, and [resolve_sheet] returns Ok(None) for it without consulting the sheet list at all. Turning iterative calculation on is a value effect reached indirectly — it changes what a circular-reference formula elsewhere evaluates to without changing that formula itself, the same shape of concern ADR-0081 raised for named-range deletion — so it stays gated as sheets-structure rather than treated as a data mutation; see crate::drive::sheets::types::IterativeCalculationSettings’s doc comment.

ADR-0073 §12 deferred this surface because batchUpdate is where “one call destroys far more than its arguments suggest”. Two properties answer that, and each is structural rather than a matter of care:

• Typed verbs, no raw request passthrough. Every verb builds its own BatchUpdateRequestItem, so the gate and --dry-run can describe the exact effect. There is no --requests file.json and deliberately no escape hatch, following ADR-0061’s handling of force-push: the dangerous form must be unreachable, not merely discouraged. This still holds for the destructive verbs added by ADR-0077 — they gained typed variants, not a passthrough.
• A distinct gate operation per risk class. Additive verbs check DriveOperation::SheetsStructure; the four destructive verbs check DriveOperation::SheetsDelete instead — never folded together, and never reusing SheetsWrite either. See each variant’s doc comment for why reuse would be silent privilege widening. StructureVerb::gate_operation is the single place this split is decided.

ADR-0075 §3/§4 originally kept deleteSheet/deleteDimension/ deleteRange unreachable at the type level, pinned by a no_destructive_request_is_reachable grep-guard test. ADR-0077 supersedes that: those requests are now reachable, but only through this module’s gated, validated path — never through a raw passthrough, and never under the sheets-structure operation an existing allow rule may already grant.

Shape follows write.rs exactly: a public wrapper that logs, an _inner that classifies then mutates, and --dry-run as an early return after the gate so a preview and a real run share one classification by construction. One difference is deliberate and tested: a dry run here does issue a single spreadsheets.get, because describing a structural effect honestly requires the sheet’s real current dimensions. It still issues no batchUpdate, and a gate-blocked attempt still issues no Sheets call at all. --dry-run for a destructive verb stays structural-only — no values.get read and no cell content in its output or the request log — and instead states a fixed caveat that formulas elsewhere in the workbook may reference what would be deleted, which cannot be checked from the sheet’s own dimensions (ADR-0077).

Structs

SheetSnapshot

The sheet a verb resolved to, plus its dimensions at that moment.

StructureOptions

Per-call options.

StructureOutcome

The full outcome of one attempt.

Enums

IterativeCalculationToggle

Which way update-workbook-properties --iterative-calculation sets iterative calculation.

StructureResult

What happened (or, under --dry-run, would happen).

StructureVerb

Which structural mutation to perform.

Functions

describe

Renders an outcome as human-readable text.

describe_lines

Renders an outcome as its individual lines, none of which contains a newline.

structure

Runs one structural mutation, logging every attempt that isn’t a dry run.