em 03: extract-first scan + full suggestion report

- ExtractFirstScanner: reads-only scan of non-local/param read expressions (member/field/property access, element access, invocation, cast), deduped by symbol+text with occurrence counts; invocations flagged (hoisting changes eval count); own-class field/property reads marked optional. Assignment LHS skipped whole (decision 5) — surfaced as a report note. - SignatureBuilder: promotes bucket overlaps into one coherent signature (declared-inside vars drop from params; declared-inside return candidates become the return; outside candidates already covered by their ref write-back stay ref params). Trailing composite returns stay void with a note suggesting an extract-variable first. - ExtractionReporter + ReportFormatter: single composition shared by CLI and tests; report = header, params (ref), returns, locals, extract-first (count + flags), notes, suggested-signature line last. - DataFlowClassifier: Returns now carry types (ReturnSuggestion) — the signature line needs them. - Displays: compact symbol/type formatting for the report. - Fixture: RepeatReads (dedupe ×2 + skipped field write), Casts (cast candidate) appended at the end so all pinned line numbers stay put.
2026-09-12 18:26:20 +01:00
parent 5d02c1aabf
commit 49a5633a7d
11 changed files with 985 additions and 68 deletions
@@ -0,0 +1,80 @@
+using System.Text;
+
+namespace ExtractMethod.Tooling;
+
+/// <summary>
+/// Renders an <see cref="ExtractionReport"/> as the human-readable extract-
+/// method suggestion report (parent spec): params (with ref), return
+/// candidates, locals, extract-first candidates (deduped, with occurrence
+/// counts and flags), the limitation notes, and the suggested signature line
+/// LAST. Pure string shaping — no Roslyn — so tests can pin the exact output
+/// the CLI prints.
+/// </summary>
+public static class ReportFormatter
+{
+    public static string Format(ExtractionReport report)
+    {
+        var sb = new StringBuilder();
+        var selection = report.Selection;
+        var suggestion = report.Suggestion;
+
+        // Header (same wording the CLI printed since em 01).
+        sb.AppendLine(
+            $"{selection.Count} statement(s) selected, lines {selection.StartLine}..{selection.EndLine} " +
+            $"in {selection.Method?.Identifier.ValueText}(): " +
+            string.Join(", ", selection.Kinds));
+
+        AppendBucket(sb, "params", suggestion.Params.Select(p =>
+            $"{p.Name} ({p.Type}){(p.ByRef ? " [ref]" : " [in]")}"));
+        AppendBucket(sb, "returns", suggestion.Returns.Select(r => $"{r.Name} ({r.Type})"));
+        AppendBucket(sb, "locals", suggestion.Locals);
+
+        if (report.ExtractFirst.Count == 0)
+        {
+            sb.AppendLine("extract-first: (none)");
+        }
+        else
+        {
+            sb.AppendLine("extract-first:");
+            foreach (var entry in report.ExtractFirst)
+            {
+                // Flags accumulate; occurrence count is always shown because
+                // "count occurrences" is the point of the dedupe.
+                var flags = new List<string>();
+                if (entry.IsInvocation)
+                {
+                    flags.Add("hoisting changes eval count");
+                }
+
+                if (entry.Optional)
+                {
+                    flags.Add($"optional: own-class {entry.OwnMemberKind}");
+                }
+
+                var flagText = flags.Count > 0 ? $" [{string.Join("; ", flags)}]" : string.Empty;
+                sb.AppendLine($"  - {entry.Text} — {entry.SymbolDisplay} ×{entry.Occurrences}{flagText}");
+            }
+        }
+
+        foreach (var note in report.Notes)
+        {
+            sb.AppendLine($"note: {note}");
+        }
+
+        var signature = report.Signature;
+        var parameterList = string.Join(", ", signature.Params.Select(p => $"{(p.ByRef ? "ref " : "")}{p.Type} {p.Name}"));
+        sb.AppendLine($"suggested signature: {signature.ReturnType} {signature.MethodName}({parameterList})");
+
+        return sb.ToString();
+    }
+
+    private static void AppendBucket(StringBuilder sb, string name, IEnumerable<string> items)
+    {
+        var enumerated = items.ToList();
+        sb.AppendLine(enumerated.Count == 0 ? $"{name}: (none)" : $"{name}: {enumerated[0]}");
+        for (var i = 1; i < enumerated.Count; i++)
+        {
+            sb.AppendLine($"{name}: {enumerated[i]}");
+        }
+    }
+}