legacy-code-doc

Legacy Code Documentation

Produce documentation for ABAP objects that have none. The output is for two audiences at once: a developer who must change the code next month, and a manager deciding whether it survives the next migration.

Prerequisites

• sap-adt-mcp ≥ 0.8.1 connected to the target system (adt_ping to verify).
• NetWeaver 7.4x+ — only core ADT read endpoints are needed (source read, search, where-used). adt_read_table examples additionally need NW 7.55+; skip data sampling on older systems.
• SAP user authorizations: repository display only (S_DEVELOP display).
• Read-only mode: fully supported — this skill never writes to SAP. (It may write the documentation to a local file if the user asks.)
• Large sources: adt_get_source output is capped per call (~64 KB). For big programs paginate with firstLine/lastLine, or slice with onlyMethod. Never assume one call returned the whole object — check truncated/totalLines.

Workflow

1. Scope the object

adt_search_objects if only a fuzzy name is known. Identify the object type — the strategy differs:

• Program (PROG): fetch the main source, then list its includes (adt_browse_package on its package, or INCLUDE statements from source) and fetch each include that carries logic.
• Class (CLAS): fetch definitions first (the public contract), then implementations method by method (onlyMethod) for the ones that matter.
• Function group (FUGR): document each function module separately (adt_get_source with type function + group); shared TOP include for state.

2. Read with a checklist

While reading, collect — don't paraphrase line by line:

• Entry points: events (START-OF-SELECTION, user-commands), public methods, FM interfaces, selection screen parameters.
• Database touchpoints: every table read (SELECT/JOIN) and especially every write (INSERT/UPDATE/MODIFY/DELETE, CALL FUNCTION ... IN UPDATE TASK). Writes are the risk register.
• External calls: RFCs, BAPIs, file I/O (OPEN DATASET, GUI_*), HTTP, authority-checks, COMMIT/ROLLBACK placement.
• Configuration coupling: hardcoded values, TVARV/Z-config table reads, sy-mandt/sy-sysid branching.
• Smells worth flagging: SELECT in loops, missing authority checks before writes, swallowed exceptions, dead branches (adt_grep_source across the package helps find copy-paste siblings).