fix(opencode-go): fallback to message table on older OpenCode DB schema

docs/providers/opencode-go.md

@@ -20,7 +20,9 @@ If neither signal exists, the plugin stays hidden.
 
 ## Data Source
 
-OpenUsage reads the local OpenCode SQLite database directly:
+OpenUsage reads the local OpenCode SQLite database directly.
+
+For current OpenCode databases it queries the `session` table:
 
 ```sql
 SELECT
@@ -32,7 +34,20 @@ WHERE json_valid(model)
   AND cost > 0
 ```
 
-Only sessions with a positive cost count. `time_updated` is stored in milliseconds (same unit as `Date.now()`), confirmed from OpenCode's [`packages/core/src/session/sql.ts`](https://github.com/anomalyco/opencode/blob/dev/packages/core/src/session/sql.ts) where `time_created` and `time_updated` use `Date.now()` as their default value. Missing remote or other-device usage is not estimated.
+If the `session` table does not yet have the `cost` and `model` columns (older local databases), it falls back to summing assistant messages from the `message` table:
+
+```sql
+SELECT
+  time_created AS createdMs,
+  CAST(coalesce(json_extract(data, '$.cost'), 0) AS TEXT) AS cost
+FROM message
+WHERE json_valid(data)
+  AND json_extract(data, '$.providerID') = 'opencode-go'
+  AND json_extract(data, '$.role') = 'assistant'
+  AND coalesce(json_extract(data, '$.cost'), 0) > 0
+```
+
+Only sessions/messages with a positive cost count. `time_updated`/`time_created` are stored in milliseconds (same unit as `Date.now()`), confirmed from OpenCode's [`packages/core/src/session/sql.ts`](https://github.com/anomalyco/opencode/blob/dev/packages/core/src/session/sql.ts) where `time_created` and `time_updated` use `Date.now()` as their default value. Missing remote or other-device usage is not estimated.
 
 ## Limits
 

plugins/opencode-go/plugin.js

@@ -29,6 +29,27 @@
       AND cost > 0
   `;
 
+  const HISTORY_EXISTS_MESSAGE_SQL = `
+    SELECT 1 AS present
+    FROM message
+    WHERE json_valid(data)
+      AND json_extract(data, '$.providerID') = 'opencode-go'
+      AND json_extract(data, '$.role') = 'assistant'
+      AND coalesce(json_extract(data, '$.cost'), 0) > 0
+    LIMIT 1
+  `;
+
+  const HISTORY_ROWS_MESSAGE_SQL = `
+    SELECT
+      time_created AS createdMs,
+      CAST(coalesce(json_extract(data, '$.cost'), 0) AS TEXT) AS cost
+    FROM message
+    WHERE json_valid(data)
+      AND json_extract(data, '$.providerID') = 'opencode-go'
+      AND json_extract(data, '$.role') = 'assistant'
+      AND coalesce(json_extract(data, '$.cost'), 0) > 0
+  `;
+
   function readNumber(value) {
     const n = Number(value);
     return Number.isFinite(n) ? n : null;
@@ -177,15 +198,41 @@
     }
   }
 
-  function hasHistory(ctx) {
-    const result = queryRows(ctx, HISTORY_EXISTS_SQL);
+  function detectSchema(ctx) {
+    const result = queryRows(
+      ctx,
+      `PRAGMA table_info(session)`
+    );
+    if (!result.ok) return { ok: false, hasSessionCostModel: false };
+    const rows = Array.isArray(result.rows) ? result.rows : [];
+    const names = new Set();
+    for (let i = 0; i < rows.length; i += 1) {
+      const row = rows[i];
+      if (row && typeof row.name === "string") names.add(row.name);
+    }
+    return {
+      ok: true,
+      hasSessionCostModel: names.has("cost") && names.has("model"),
+    };
+  }
+
+  function historyExistsSql(hasSessionCostModel) {
+    return hasSessionCostModel ? HISTORY_EXISTS_SQL : HISTORY_EXISTS_MESSAGE_SQL;
+  }
+
+  function historyRowsSql(hasSessionCostModel) {
+    return hasSessionCostModel ? HISTORY_ROWS_SQL : HISTORY_ROWS_MESSAGE_SQL;
+  }
+
+  function hasHistory(ctx, schema) {
+    const result = queryRows(ctx, historyExistsSql(schema.hasSessionCostModel));
     if (!result.ok) return { ok: false, present: false };
     return { ok: true, present: result.rows.length > 0 };
   }
 
-  function loadHistory(ctx) {
+  function loadHistory(ctx, schema) {
     // time_updated is in milliseconds (same unit as Date.now()), confirmed from OpenCode source
-    const result = queryRows(ctx, HISTORY_ROWS_SQL);
+    const result = queryRows(ctx, historyRowsSql(schema.hasSessionCostModel));
     if (!result.ok) return result;
 
     const rows = [];
@@ -260,7 +307,8 @@
 
   function probe(ctx) {
     const authKey = loadAuthKey(ctx);
-    const history = hasHistory(ctx);
+    const schema = detectSchema(ctx);
+    const history = hasHistory(ctx, schema);
     const detected = !!authKey || (history.ok && history.present);
 
     if (!detected) {
@@ -271,7 +319,7 @@
       return { plan: "Go", lines: buildSoftEmptyLines(ctx) };
     }
 
-    const rowsResult = loadHistory(ctx);
+    const rowsResult = loadHistory(ctx, schema);
     if (!rowsResult.ok) {
       return { plan: "Go", lines: buildSoftEmptyLines(ctx) };
     }

plugins/opencode-go/plugin.test.js

@@ -20,25 +20,54 @@ function setAuth(ctx, value = "go-key") {
 
 function setHistoryQuery(ctx, rows, options = {}) {
   const list = Array.isArray(rows) ? rows : [];
+  const hasSessionCostModel = options.hasSessionCostModel !== false;
   ctx.host.sqlite.query.mockImplementation((dbPath, sql) => {
     expect(dbPath).toBe("~/.local/share/opencode/opencode.db");
 
+    if (String(sql).includes("PRAGMA table_info")) {
+      const columns = [
+        { name: "id" },
+        { name: "project_id" },
+        { name: "time_created" },
+        { name: "time_updated" },
+      ];
+      if (hasSessionCostModel) {
+        columns.push({ name: "cost" }, { name: "model" });
+      }
+      return JSON.stringify(columns);
+    }
+
     if (String(sql).includes("SELECT 1 AS present")) {
       if (options.assertFilters !== false) {
-        expect(String(sql)).toContain(
-          "json_extract(model, '$.providerID') = 'opencode-go'",
-        );
-        expect(String(sql)).toContain("cost > 0");
+        if (hasSessionCostModel) {
+          expect(String(sql)).toContain(
+            "json_extract(model, '$.providerID') = 'opencode-go'",
+          );
+          expect(String(sql)).toContain("cost > 0");
+        } else {
+          expect(String(sql)).toContain(
+            "json_extract(data, '$.providerID') = 'opencode-go'",
+          );
+          expect(String(sql)).toContain("json_extract(data, '$.role') = 'assistant'");
+        }
       }
       return JSON.stringify(list.length > 0 ? [{ present: 1 }] : []);
     }
 
     if (options.assertFilters !== false) {
-      expect(String(sql)).toContain(
-        "json_extract(model, '$.providerID') = 'opencode-go'",
-      );
-      expect(String(sql)).toContain("time_updated");
-      expect(String(sql)).toContain("cost > 0");
+      if (hasSessionCostModel) {
+        expect(String(sql)).toContain(
+          "json_extract(model, '$.providerID') = 'opencode-go'",
+        );
+        expect(String(sql)).toContain("time_updated");
+        expect(String(sql)).toContain("cost > 0");
+      } else {
+        expect(String(sql)).toContain(
+          "json_extract(data, '$.providerID') = 'opencode-go'",
+        );
+        expect(String(sql)).toContain("json_extract(data, '$.role') = 'assistant'");
+        expect(String(sql)).toContain("time_created");
+      }
     }
 
     return JSON.stringify(list);
@@ -251,6 +280,24 @@ describe("opencode-go plugin", () => {
     expect(result.lines[0].used).toBe(5);
   });
 
+  it("falls back to message table when session cost/model columns are missing", async () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-03-06T12:00:00.000Z"));
+
+    const ctx = makeCtx();
+    setHistoryQuery(
+      ctx,
+      [{ createdMs: Date.parse("2026-03-06T11:00:00.000Z"), cost: 3 }],
+      { hasSessionCostModel: false },
+    );
+
+    const plugin = await loadPlugin();
+    const result = plugin.probe(ctx);
+
+    expect(result.plan).toBe("Go");
+    expect(result.lines[0].used).toBe(25);
+  });
+
   it("returns a soft empty state when sqlite returns malformed JSON and auth exists", async () => {
     const ctx = makeCtx();
     setAuth(ctx);