Case 120: Internal struct fields reordered (non-public, scoped)¶

Field	Value
Verdict	✅ NO_CHANGE
Category	No Change
Platforms	Linux, macOS, Windows
Flags	—
Detected `ChangeKind`s	—
Source files	`examples/case120_internal_struct_reordered_scoped/`

Category: Public-surface scoping (ADR-024) | Verdict: ✅ NO_CHANGE (exit 0, with --scope-public-headers)

What changes¶

The fields of struct InternalStats are reordered (calls/total swapped), changing field offsets. Reordering members is normally an ABI break — but InternalStats is not on the public ABI surface: no exported, header-declared public function reaches it. The public API (Point, translate) is unchanged.

Why this is not a false positive¶

A consumer linking against the public API cannot observe the internal layout of InternalStats, so reordering its fields cannot break it. With ADR-024 public-surface scoping the offset change is recorded in the filtered audit ledger rather than reported, and the verdict is NO_CHANGE.

abicheck compare libfoo_v1.so libfoo_v2.so -H v1.h \
    --scope-public-headers --show-filtered
# verdict: NO_CHANGE (exit 0); filtered finding(s) on InternalStats

This relies on reachability, not on a name heuristic: the moment a public API references InternalStats, the same reordering is reported as breaking — so scoping reduces noise without hiding real breaks.

How to fix¶

N/A — confined to an internal type, this is the intended compatible outcome.

Source files¶

app.c
v1.c
v1.h
v2.c
v2.h