pull Command - Conflict Detection

Overview

Conflict detection prevents silent overwrites when an ABAP object has been modified locally (in ADT/SE80) since the last pull, or when switching to a branch whose content has diverged. It is enabled by default — every pull checks for conflicts and aborts if any are found.

The Problem

Without conflict detection, pull calls abapGit’s deserialize() unconditionally:

1. Developer pulls from git → starts editing object in ADT
2. Developer runs pull again → ADT edits are silently overwritten

Or across branches:

Developer pulls branch b1 (baseline recorded)
Developer switches to branch b2 (different content for the same object)
Developer runs pull → b2 content overwrites b1 without warning

Three Conflict Types

LOCAL_EDIT

The system object was modified in ADT/SE80 after the last pull, but git content is unchanged. Pulling would silently overwrite local edits.

Pull (baseline SHA recorded)
  → Object edited in ADT                  ← system diverged from baseline
  → Pull same branch again → LOCAL_EDIT conflict

SYSTEM_EDIT

Both the ABAP system and git were modified since the last pull. Both sides diverged.

Pull (baseline SHA recorded)
  → Object edited in ADT                  ← system diverged
  → Someone pushes a new version to git   ← git also diverged
  → Pull again → SYSTEM_EDIT conflict

BRANCH_SWITCH

Switching to a branch whose content differs from what was last pulled, and a different user performed the last pull. Only fires when another developer’s pull is at risk of being silently overridden.

Developer A pulls branch b1 (baseline: branch=b1, sha=abc, last_pulled_by=A)
  → Developer B pulls branch b2 where same object has sha=xyz
  → BRANCH_SWITCH conflict (last_pulled_by=A ≠ sy-uname=B)

Same-user branch switches are always safe — if you pulled branch b1 and now want to pull b2, it passes through:

You pull branch b1 (baseline: branch=b1, sha=abc, last_pulled_by=YOU)
  → You pull branch b2 (different content)
  → No conflict — intentional branch switch by same user

How It Works

Tracking Table: `ZABGAGT_OBJ_META`

After every successful pull, a baseline is written to this transparent table:

Field	Type	Description
`obj_type` (key)	`tadir-object`	Object type (CLAS, INTF, …)
`obj_name` (key)	`tadir-obj_name`	Object name
`devclass`	`devclass`	Package (refreshed from TADIR on every pull — handles package moves)
`last_git_sha`	`string(40)`	SHA of the pulled file content
`last_branch`	`string(255)`	Branch that was pulled
`last_pulled_at`	`timestampl`	When the pull happened
`last_pulled_by`	`syuname`	Who performed the pull
`sys_changed_by`	`syuname`	Who last pulled (stored for conflict report)

Detection Logic

Before calling deserialize(), for each file being pulled:

current_sha     = SHA-1( incoming git file content )
local_sha       = SHA-1( current ABAP system content, via get_files_local() )

git_changed     = current_sha ≠ last_git_sha      (git changed since last pull)
sys_changed     = local_sha   ≠ last_git_sha       (system changed since last pull)
branch_switched = current_branch ≠ last_branch
different_user  = last_pulled_by ≠ sy-uname

Idempotent exit (checked first):
  local_sha = current_sha → system already has the incoming content → skip all checks

SYSTEM_EDIT:    git_changed AND sys_changed
BRANCH_SWITCH:  git_changed AND branch_switched AND different_user
LOCAL_EDIT:     sys_changed AND NOT git_changed

Safe (no conflict):
  - git changed only, same branch           → fast-forward update
  - branch switched, same SHA              → branches have identical content
  - branch switched, same user             → intentional switch, safe
  - local_sha = current_sha (any scenario) → idempotent pull, system already up to date
  - no baseline (first pull)               → skipped, baseline created after pull

Why Content SHA (Not Timestamps)

VRSD (SAP version management) is only updated when objects are added to transport requests. Objects in local packages (prefix $) never get VRSD entries, making timestamp-based detection unreliable. Content SHA comparison works for all package types.

Bootstrap Behavior (First Pull)

No baseline exists → conflict detection is skipped → pull always succeeds → baseline written.

Pull #	Baseline exists?	Conflict detection
1st	No	Skipped — baseline created
2nd+	Yes	Active

Output

Conflict Aborted

⚠️  Pull aborted — 1 conflict(s) detected

────────────────────────────────────────────────────────────────────────────────
Pull aborted — 1 conflict(s) detected

Object:        CLAS ZCL_MY_CLASS
Conflict type: LOCAL_EDIT
System modified after last pull by DEVELOPER1
Git content unchanged — pull would overwrite local edits

To override: abapgit-agent pull --conflict-mode ignore

Object:        CLAS ZCL_MY_CLASS
Conflict type: SYSTEM_EDIT
Git changed:   abc1234... → def5678...
System changed by DEVELOPER2 (after last pull by DEVELOPER1)

Object:        CLAS ZCL_MY_CLASS
Conflict type: BRANCH_SWITCH
Branch:        main → feature/my-branch
Git changed:   abc1234... → xyz9876...
Last pull by DEVELOPER1 (different user) — unexpected branch state

No Conflicts

Pull proceeds as normal — no additional output. Baseline is silently updated after each successful pull.

Implementation Files

File	Description
`abap/zabgagt_obj_meta.tabl.xml`	Metadata tracking table
`abap/zif_abgagt_conflict_detector.intf.abap`	Conflict detector interface
`abap/zcl_abgagt_conflict_detector.clas.abap`	Core detection logic
`abap/zcl_abgagt_conflict_detector.clas.testclasses.abap`	ABAP unit tests (19 tests)
`abap/zif_abgagt_agent.intf.abap`	`iv_conflict_mode` added to `pull()`
`abap/zcl_abgagt_agent.clas.abap`	Conflict check + metadata store in `pull()`
`abap/zcl_abgagt_command_pull.clas.abap`	`conflict_mode` in params struct
`src/commands/pull.js`	`--conflict-mode` flag
`tests/integration/conflict-runner.js`	Integration tests (5 scenarios)

Configuration

CLI Flag (highest priority)

abapgit-agent pull --conflict-mode ignore   # bypass for this run
abapgit-agent pull --conflict-mode abort    # force on for this run

Project Config (`.abapgit-agent.json`)

Set the default mode for all developers on a project:

{
  "conflictDetection": {
    "mode": "ignore",
    "reason": "Single-developer project — conflict detection not needed"
  }
}

Field	Values	Default	Description
`mode`	`"abort"`, `"ignore"`	`"abort"`	Default conflict detection behaviour
`reason`	string	`null`	Optional explanation (not currently shown in output)

Precedence

CLI --conflict-mode flag  >  .abapgit-agent.json conflictDetection.mode  >  "abort"

Key Behaviors

Always on by default — abort is the default; use --conflict-mode ignore or project config to bypass
First pull always succeeds — no baseline yet, detection skipped
Per-object tracking — each object has its own baseline
Content SHA, not timestamps — works for all package types including local $ packages
Store after success only — baseline never updated when pull fails or is aborted
DEVCLASS auto-refreshed — devclass is read from TADIR on every pull; package moves are handled automatically
Idempotent pulls are safe — if the system already has the incoming content (local_sha = current_sha), all conflict checks are skipped. This handles “edit in ADT → export to git → commit → pull” without false positives.
BRANCH_SWITCH is user-aware — only fires when a different user last pulled from another branch (unexpected shared-system state). Same user switching branches intentionally always passes through.