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Alexander Liberov edited this page Nov 5, 2026 · 1 revision

Opaque to analysis (opaque-to-analysis)

A project-wide lint rule, severity info, OFF by default: a routine whose calls that do not provably leave the project are predominantly calls the index cannot resolve.

This is a rule about the limits of drag-lint's own analysis, not a complaint about the code. impact, find-callers, call trees and dead-code detection all stand on call_edges. In a routine made mostly of calls with no edge, they see almost nothing, and a reader of those answers should know that.

Running it from the CLI

drag-lint lint-all --db <project.sqlite> --db <library.sqlite> --rule opaque-to-analysis
drag-lint lint-all --db <project.sqlite> --db <library.sqlite> --enable opaque-to-analysis
drag-lint lint <unit.pas> --db <project.sqlite> --library-db <library.sqlite> --rule opaque-to-analysis

What it reports

One finding per routine, at its implementation line, for example:

uContainerConfig.RegisterDependencies: 137 of 137 calls that do not provably leave the project could not be resolved (AsSingleton, AsSingletonPerThread, Build) -- impact analysis, call trees and dead-code detection are blind inside this routine

It fires at 3 or more opaque calls that make up 60 percent or more of (opaque calls + calls with a call_edges row). An ambiguous edge counts as resolved.

What counts as opaque

  • A procedural value: a parameter, local or field called like a routine.
  • A member of a receiver the index could not type, such as a chain through a cast, or var X := Foo.Create (X.Bar has no type text today).
  • A project routine or member the resolver declined to pick, for example an overload tie.

What is left out of both figures

  • Compiler intrinsics and type casts (Exit, Length, Writeln, Integer(x), TFoo(x)).
  • A stored refs.external_target.
  • A receiver typed by a name the project does not declare (FMemTable.Post): the type is known, and it is not ours.
  • A project-typed receiver whose chain does not declare the member: it is inherited from outside.
  • A call the library oracle binds live (Application.ProcessMessages, CodeSite.Send, an inherited Close, Format).

Dispatch into project code through a library virtual or an event is NOT counted as opaque. The rule measures what the index cannot place, not every path it cannot follow.

Without a library index the rule stays SILENT: every RTL and VCL call would read as opaque.

How the thresholds were picked

Measured 2026-11-04 on 1.42.0-alpha indexes, before the thresholds were fixed:

Project Routines with 2+ opaque calls 3+ and 50% 3+ and 60% (shipped) 3+ and 80% 5+ and 60%
ORM3 CLIENT 33 17 15 14 9
ORM3 SERVER 24 10 10 6 5
YADF 33 13 12 6 5

These rows predate a last addition to the intrinsic list (file I/O: Writeln, Rewrite, CloseFile). With it, and the shipped thresholds, the final counts are:

Project Findings Opaque calls in them
ORM3 CLIENT 14 91
ORM3 SERVER 9 582
YADF 12 54
drag-lint engine 244 1879

The engine's count is mostly var X := ... locals, which have no type text in the index.

The measurement also changed the premise. The charts team's SendDeltaOperation (32 calls, 2 edges) read as 30 unresolvable interface dispatches. With the library judged properly, the rest are TFDMemTable and TMemoryStream calls, RTL routines and bindable heads, and the routine does not fire.

To suppress a finding: // dl:ok opaque-to-analysis -- <reason> on the routine's line.

Guard: tests\autotest\run_opaque_to_analysis.ps1 (fixture tests\lint-project\opaque-to-analysis).

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