fix(ui): read every footer of a search answer

The server writes next_offset and truncation_reason under a full page,
candidate_window_saturated for very many candidates, and the lines of a
too small output budget. The search parser knew none of them, so every
search with more than one page fell back to "Index search unavailable".

Signed-off-by: Bernhard Jackiewicz <bj@techport.io>

graph-ui/src/provider/compact-rows.search-footers.test.ts

@@ -0,0 +1,92 @@
+import { describe, expect, it } from 'vitest';
+
+import { parseSearchResults } from './compact-rows';
+
+/*
+ * Handtest 04.10.: In cbm meldete die Galaxy-Suche bei vielen Begriffen
+ * "Index search unavailable". Der Server schreibt unter eine Suchantwort mehr
+ * Fusszeilen, als der Parser kannte (bm25_emit_metadata_tree in src/mcp/mcp.c):
+ * next_offset und truncation_reason schon bei einer vollen Seite,
+ * candidate_window_saturated bei sehr vielen Kandidaten, und bei einem zu
+ * kleinen Ausgabebudget max_output_bytes, continuation_requires_higher_budget,
+ * output_budget_floor_exceeded und hint. Jede davon liess die Suche scheitern.
+ */
+
+/** Wie der Server auf search_graph {project: cbm, query: working, limit: 3} antwortet. */
+const PAGED = [
+    'results: 3  (cols: qn label file lines rank)',
+    '  cbm.graph-ui.tools.freshclone-check.workingTreeChanges Function graph-ui/tools/freshclone-check.mjs 112-138 -15.29',
+    '  cbm.__branch__.working-tree Branch {} - -14.24',
+    '  cbm.tests.test_cypher.cypher_with_alias_stays_in_scope_issue1919 Function tests/test_cypher.c 2151-2164 -12.2',
+    'total: 14',
+    'total_relation: eq',
+    'search_mode: bm25',
+    'returned: 3',
+    'has_more: true',
+    'next_offset: 3',
+    'truncated: true',
+    'truncation_reason: page_limit',
+    '',
+].join('\n');
+
+describe('parseSearchResults reads every footer the server writes', () => {
+    it('reads a full page with next_offset and truncation_reason', () => {
+        const parsed = parseSearchResults(PAGED);
+        expect(parsed.rows).toHaveLength(3);
+        expect(parsed.total).toBe(14);
+        expect(parsed.hasMore).toBe(true);
+        expect(parsed.nextOffset).toBe(3);
+        expect(parsed.truncated).toBe(true);
+        expect(parsed.truncationReason).toBe('page_limit');
+    });
+
+    it('reads a saturated candidate window', () => {
+        const saturated = [
+            'results: 1  (cols: qn label)',
+            '  a.b.c Function',
+            'total: 1',
+            'total_relation: gte',
+            'candidate_window_saturated: true',
+            'search_mode: bm25',
+            'returned: 1',
+            'has_more: false',
+            'truncated: true',
+            'truncation_reason: candidate_window',
+            '',
+        ].join('\n');
+        const parsed = parseSearchResults(saturated);
+        expect(parsed.totalRelation).toBe('gte');
+        expect(parsed.candidateWindowSaturated).toBe(true);
+        expect(parsed.truncationReason).toBe('candidate_window');
+        expect(parsed.rows).toHaveLength(1);
+    });
+
+    it('reads the lines of a too small output budget', () => {
+        const budget = [
+            'results: 0  (cols: qn label)',
+            'total: 5',
+            'total_relation: eq',
+            'search_mode: bm25',
+            'returned: 0',
+            'has_more: true',
+            'continuation_requires_higher_budget: true',
+            'truncated: true',
+            'truncation_reason: output_budget',
+            'max_output_bytes: 200',
+            'output_budget_floor_exceeded: true',
+            'hint: "first identity row exceeds max_output_bytes; raise max_output_bytes"',
+            '',
+        ].join('\n');
+        const parsed = parseSearchResults(budget);
+        expect(parsed.rows).toHaveLength(0);
+        expect(parsed.truncationReason).toBe('output_budget');
+        expect(parsed.maxOutputBytes).toBe(200);
+        expect(parsed.continuationRequiresHigherBudget).toBe(true);
+        expect(parsed.outputBudgetFloorExceeded).toBe(true);
+        expect(parsed.hint).toContain('max_output_bytes');
+    });
+
+    it('still rejects a line it does not know', () => {
+        expect(() => parseSearchResults(PAGED.replace('truncation_reason: page_limit', 'surprise: 1'))).toThrow(/unbekannte Zeile/);
+    });
+});

graph-ui/src/provider/compact-rows.ts

@@ -63,8 +63,23 @@ export interface SearchResults {
     returned?: number;
     totalRelation?: string;
     truncated?: boolean;
+    /** Was bm25_emit_metadata_tree (src/mcp/mcp.c) ausserdem schreibt: die naechste Seite,
+     * warum gekappt wurde, ein gesaettigtes Kandidatenfenster und ein zu kleines Budget. */
+    nextOffset?: number;
+    truncationReason?: string;
+    candidateWindowSaturated?: boolean;
+    continuationRequiresHigherBudget?: boolean;
+    maxOutputBytes?: number;
+    outputBudgetFloorExceeded?: boolean;
+    hint?: string;
 }
 
+/** Fusszeilen der Suchantwort mit Zahl, Wahrheitswert oder Text (Handtest 04.10.: jede
+ * unbekannte liess die Suche mit "Index search unavailable" scheitern). */
+const SEARCH_NUMBER_LINE = /^(next_offset|max_output_bytes):\s*(\d+)\s*$/;
+const SEARCH_FLAG_LINE = /^(candidate_window_saturated|continuation_requires_higher_budget|output_budget_floor_exceeded):\s*(true|false)\s*$/;
+const SEARCH_TEXT_LINE = /^(truncation_reason|hint):\s*(.*)$/;
+
 const ROWS_HEAD = /^rows:\s*(\d+)\s*\(cols:\s*([^)]*)\)\s*$/;
 const RESULTS_HEAD = /^results:\s*(\d+)\s*\(cols:\s*([^)]*)\)\s*$/;
 const TOTAL_LINE = /^total:\s*(\d+)\s*$/;
@@ -341,6 +356,7 @@ export function parseSearchResults(text: string): SearchResults {
     let totalRelation: string | undefined;
     let truncated: boolean | undefined;
     let refs: ReadonlyMap<number, string> | undefined;
+    const footers: Pick<SearchResults, 'nextOffset' | 'truncationReason' | 'candidateWindowSaturated' | 'continuationRequiresHigherBudget' | 'maxOutputBytes' | 'outputBudgetFloorExceeded' | 'hint'> = {};
 
     let i = 0;
     while (i < lines.length) {
@@ -394,6 +410,26 @@ export function parseSearchResults(text: string): SearchResults {
             i += 1;
             continue;
         }
+        const numberMatch = SEARCH_NUMBER_LINE.exec(line);
+        if (numberMatch !== null) {
+            footers[numberMatch[1] === 'next_offset' ? 'nextOffset' : 'maxOutputBytes'] = Number.parseInt(numberMatch[2], 10);
+            i += 1;
+            continue;
+        }
+        const flagMatch = SEARCH_FLAG_LINE.exec(line);
+        if (flagMatch !== null) {
+            const key = flagMatch[1] === 'candidate_window_saturated' ? 'candidateWindowSaturated'
+                : flagMatch[1] === 'continuation_requires_higher_budget' ? 'continuationRequiresHigherBudget' : 'outputBudgetFloorExceeded';
+            footers[key] = flagMatch[2] === 'true';
+            i += 1;
+            continue;
+        }
+        const textMatch = SEARCH_TEXT_LINE.exec(line);
+        if (textMatch !== null) {
+            footers[textMatch[1] === 'truncation_reason' ? 'truncationReason' : 'hint'] = unquote(textMatch[2].trim());
+            i += 1;
+            continue;
+        }
         const head = RESULTS_HEAD.exec(line);
         if (head !== null) {
             declared = Number.parseInt(head[1], 10);
@@ -426,7 +462,7 @@ export function parseSearchResults(text: string): SearchResults {
         throw new Error('Suchantwort ohne has_more-Zeile');
     }
 
-    const out: SearchResults = { total, mode, columns, rows, hasMore };
+    const out: SearchResults = { total, mode, columns, rows, hasMore, ...footers };
     if (returned !== undefined) {
         out.returned = returned;
     }