fix: what the batch C review found

- A redirect followed for a custom base URL (quota on) no longer carries
  the user's key or cookies to another origin, as fetch itself does, and
  a private address may redirect to another private one (already counted).
- The admin Test of an Ollama or Vertex AI entry without a URL goes where
  chat sends that entry's key: the environment's own URL variable, for
  Ollama else the local default. The Test of an Ollama Cloud key without
  a URL went to the cloud while chat went to local Ollama.
- Chat saves: each save notes the chat on screen and the order of the
  reads before reading its data. A save read before switching chats no
  longer writes into the chat switched to, and a copy that waited for its
  thumbnail no longer replaces a newer one.
- "Continue without saving" keeps its button when a later auto-save fails,
  and goes away when a new message is sent.
- A screenshot check that was waiting for its image when the user pressed
  Stop stays skipped after the next message.
- MCP History: draw.io's own copy of a diagram (after get_diagram) no
  longer adds an entry without a picture; a change of background is still
  its own version. The tab ignores an edit's answer that arrives after a
  newer AI write loaded.
- Desktop: a deleted preset is not brought back by a failed switch, and a
  request naming no preset does not stop a rollback. An origin keeping
  an access code counts as having settings.
- .env: a quoted value ending in a backslash ("C:\dir\") is read as dotenv
  reads it.
- The tool card no longer crashes on an id that does not turn into text;
  an older Test's success timer no longer ends a newer Test's spinner.
- Tests that passed without their fix now check it.

tests/unit/admin-test-model.test.ts

@@ -11,13 +11,19 @@ vi.mock("@/app/api/validate-model/route", () => ({
     },
 }))
 vi.mock("@/lib/admin/auth", () => ({ checkAdminAuth: () => null }))
-vi.mock("@/lib/admin/settings", () => ({ loadSettings: () => ({}) }))
+// The environment's own values, under the panel's settings
+const envFallback = vi.hoisted(() => ({ values: {} as Record<string, string> }))
+vi.mock("@/lib/admin/settings", () => ({
+    loadSettings: () => ({}),
+    getEnvFallback: (key: string) => envFallback.values[key] ?? null,
+}))
 
 import { POST as testModel } from "@/app/api/admin/test-model/route"
 
 const ENV = ["OPENAI_BASE_URL", "SGLANG_BASE_URL", "AI_GATEWAY_BASE_URL"]
 const saved: Record<string, string | undefined> = {}
 beforeEach(() => {
+    envFallback.values = {}
     for (const k of ENV) {
         saved[k] = process.env[k]
         delete process.env[k]
@@ -74,8 +80,25 @@ describe("admin Test of an entry without a URL", () => {
         try {
             await test({ provider: "vertexai", vertexApiKey: "new-key" })
             expect(sent.body.baseUrl).toBeUndefined()
+            // The environment's own URL, which chat uses once it is saved
+            envFallback.values.GOOGLE_VERTEX_BASE_URL =
+                "https://vertex-proxy.example.com"
+            await test({ provider: "vertexai", vertexApiKey: "new-key" })
+            expect(sent.body.baseUrl).toBe("https://vertex-proxy.example.com")
+            expect(sent.body.serverBaseUrl).toBe(true)
         } finally {
             delete process.env.GOOGLE_VERTEX_BASE_URL
         }
     })
+
+    it("tests Ollama where chat sends the entry's key", async () => {
+        // Chat on the saved entry: OLLAMA_BASE_URL of the environment, else
+        // the SDK's local default (the Test used to go to Ollama Cloud)
+        await test({ provider: "ollama", apiKey: "k" })
+        expect(sent.body.baseUrl).toBe("http://127.0.0.1:11434/api")
+        expect(sent.body.serverBaseUrl).toBe(true)
+        envFallback.values.OLLAMA_BASE_URL = "http://gpu:11434/api"
+        await test({ provider: "ollama", apiKey: "k" })
+        expect(sent.body.baseUrl).toBe("http://gpu:11434/api")
+    })
 })

tests/unit/ai-providers-credentials.test.ts

@@ -11,6 +11,7 @@ const settings = vi.hoisted(() => ({ values: {} as Record<string, string> }))
 
 vi.mock("@/lib/admin/settings", () => ({
     loadSettings: () => settings.values,
+    getEnvFallback: (key: string) => process.env[key] ?? null,
 }))
 
 vi.mock("@ai-sdk/google-vertex", () => {

tests/unit/app-menu.test.ts

@@ -21,6 +21,7 @@ const state = vi.hoisted(() => ({
 }))
 vi.mock("@/electron/main/config-manager", () => ({
     applyPresetToEnv: (id: string) => {
+        if (id === "missing") return null
         state.current = id
         return { AI_PROVIDER: id }
     },
@@ -80,4 +81,24 @@ describe("switchPreset", () => {
         await third
         expect(state.current).toBe("B")
     })
+
+    it("does not bring back the old preset over a deletion", async () => {
+        const toB = switchPreset("B").catch(() => {})
+        // B is deleted while its restart is pending
+        state.current = null
+        state.restarts[0].reject(new Error("timed out"))
+        await toB
+        expect(state.current).toBeNull()
+        expect(state.restarts).toHaveLength(1)
+    })
+
+    it("still rolls back when a later request named no preset", async () => {
+        const toB = switchPreset("B").catch(() => {})
+        await expect(switchPreset("missing")).rejects.toThrow("not found")
+        state.restarts[0].reject(new Error("timed out"))
+        await new Promise((r) => setTimeout(r, 0))
+        state.restarts[1]?.resolve()
+        await toB
+        expect(state.current).toBe("A")
+    })
 })

tests/unit/chat-route-quota.test.ts

@@ -163,11 +163,13 @@ describe("chat quota", () => {
 
     it("does not count a provider that never uses the base URL header", async () => {
         // Bedrock on the user's own AWS keys goes to AWS, whatever the
-        // leftover base URL says
+        // leftover base URL says (with a key header too, so the request gets
+        // past the custom URL check to the quota decision)
         const res = await send({
             "x-ai-provider": "bedrock",
             "x-ai-model": "amazon.nova-lite-v1:0",
             "x-ai-base-url": "http://127.0.0.1:8080",
+            "x-ai-api-key": "leftover",
             "x-aws-access-key-id": "id",
             "x-aws-secret-access-key": "secret",
             "x-aws-region": "us-east-1",

tests/unit/env-loader.test.ts

@@ -28,6 +28,8 @@ const KEYS = [
     "T_ESC_HASH",
     "T_ESC_INNER",
     "T_ESC_COMMENT",
+    "T_DIR",
+    "T_DIR_COMMENT",
 ]
 afterEach(() => {
     for (const k of KEYS) delete process.env[k]
@@ -92,4 +94,18 @@ describe("loadEnvFile", () => {
         expect(process.env.T_ESC_INNER).toBe('a # \\"b\\"')
         expect(process.env.T_ESC_COMMENT).toBe('x\\"y')
     })
+
+    it("keeps a backslash before the closing quote, like dotenv", () => {
+        dir.path = mkdtempSync(join(tmpdir(), "env-loader-"))
+        writeFileSync(
+            join(dir.path, ".env"),
+            ['T_DIR="C:\\dir\\"', 'T_DIR_COMMENT="C:\\data\\" # dir'].join(
+                "\n",
+            ),
+        )
+        loadEnvFile()
+        // Windows folders; dotenv 16.6.1 reads them the same
+        expect(process.env.T_DIR).toBe("C:\\dir\\")
+        expect(process.env.T_DIR_COMMENT).toBe("C:\\data\\")
+    })
 })

tests/unit/mcp-preview-recovery.test.ts

@@ -238,6 +238,27 @@ describe("MCP preview after the server recreated its session", () => {
         expect(t.next("POST").body.xml).toBe("<mxfile>A</mxfile>")
     })
 
+    it("ignores an edit's answer that comes after a newer AI write loaded", async () => {
+        const t = await inStep()
+        t.fromDrawio({ event: "autosave", xml: "<mxfile>B</mxfile>" })
+        t.fromDrawio({ event: "export", data: "<svg/>" })
+        await t.settle()
+        const pushB = t.next("POST")
+        // The AI wrote X after B; the poll's answer comes first
+        const poll = t.page.poll()
+        t.next("GET").answer(state("S1", 4, "<mxfile>X</mxfile>"))
+        await poll
+        pushB.answer({ status: 200, body: { success: true, version: 3 } })
+        await t.settle()
+        await t.settle()
+        expect(t.page.read()).toMatchObject({
+            currentVersion: 4,
+            lastXml: "<mxfile>X</mxfile>",
+        })
+        // No push of the AI's diagram as the user's edit
+        expect(t.calls.filter((c) => c.method === "POST")).toHaveLength(0)
+    })
+
     it("sends nothing more after a sync reply", async () => {
         const t = await inStep()
         const poll = t.page.poll()
@@ -298,13 +319,27 @@ describe("MCP preview thumbnails and downloads", () => {
 
     it("drops the reply to an older thumbnail export", async () => {
         const { t, n } = await loadedB()
+        // The next AI write loads before draw.io answered the first export
+        const poll = t.page.poll()
+        t.next("GET").answer(state("S1", 4, "<mxfile>C</mxfile>"))
+        await poll
+        await new Promise((r) => setTimeout(r, 600))
+        const newer = t.toDrawio.at(-1).thumbExport
+        expect(newer).toBeGreaterThan(n)
         t.fromDrawio({
             event: "export",
-            data: "<svg/>",
-            message: { thumbExport: n - 1 },
+            data: "<svg>B</svg>",
+            message: { thumbExport: n },
         })
         await t.settle()
         expect(thumbnailPosts(t)).toHaveLength(0)
+        t.fromDrawio({
+            event: "export",
+            data: "<svg>C</svg>",
+            message: { thumbExport: newer },
+        })
+        await t.settle()
+        expect(thumbnailPosts(t).map((c) => c.body.version)).toEqual([4])
     })
 
     it("drops the image when the user changed the canvas since the load", async () => {
@@ -312,11 +347,17 @@ describe("MCP preview thumbnails and downloads", () => {
         t.fromDrawio({ event: "autosave", xml: "<mxfile>B edited</mxfile>" })
         t.fromDrawio({
             event: "export",
-            data: "<svg/>",
+            data: "<svg>thumbnail</svg>",
             message: { thumbExport: n },
         })
         await t.settle()
         expect(thumbnailPosts(t)).toHaveLength(0)
+        // The edit is saved with the image of its own export
+        t.fromDrawio({ event: "export", data: "<svg>edit</svg>" })
+        await t.settle()
+        const push = t.next("POST")
+        expect(push.body.xml).toBe("<mxfile>B edited</mxfile>")
+        expect(atob(push.body.svg.split(",")[1])).toBe("<svg>edit</svg>")
     })
 
     it("downloads the canvas with an edit the server did not get", async () => {

tests/unit/ssrf-protection.test.ts

@@ -143,6 +143,58 @@ describe("redirectGuardedFetch with the quota on", () => {
         expect(fetch).toHaveBeenCalledTimes(1)
     })
 
+    it("follows a private address's redirect to another one", async () => {
+        // Counted as the server's from the start
+        vi.stubGlobal(
+            "fetch",
+            answers({
+                "http://10.0.0.5:4000/v1/chat": new Response(null, {
+                    status: 307,
+                    headers: { location: "http://10.0.0.6:4000/v1/chat" },
+                }),
+                "http://10.0.0.6:4000/v1/chat": new Response("ok"),
+            }),
+        )
+        const res = await redirectGuardedFetch()?.(
+            "http://10.0.0.5:4000/v1/chat",
+            { method: "POST", body: "{}" },
+        )
+        expect(await res?.text()).toBe("ok")
+    })
+
+    it("sends no credentials to another origin", async () => {
+        const fetchMock = answers({
+            "https://proxy.example/v1/chat": new Response(null, {
+                status: 307,
+                headers: { location: "https://other.example/v1/chat" },
+            }),
+            "https://other.example/v1/chat": new Response("ok"),
+        })
+        vi.stubGlobal("fetch", fetchMock)
+        await redirectGuardedFetch()?.("https://proxy.example/v1/chat", {
+            method: "POST",
+            body: "{}",
+            headers: {
+                Authorization: "Bearer user-key",
+                Cookie: "eo_token=1",
+                "Content-Type": "application/json",
+            },
+        })
+        const sent = (call: number) =>
+            new Headers(
+                (
+                    fetchMock.mock.calls[call] as unknown as [
+                        string,
+                        RequestInit,
+                    ]
+                )[1].headers,
+            )
+        expect(sent(0).get("authorization")).toBe("Bearer user-key")
+        expect(sent(1).get("authorization")).toBeNull()
+        expect(sent(1).get("cookie")).toBeNull()
+        expect(sent(1).get("content-type")).toBe("application/json")
+    })
+
     it("is not used without the quota", () => {
         delete process.env.DYNAMODB_QUOTA_TABLE
         expect(redirectGuardedFetch()).toBeUndefined()

tests/unit/tool-call-card.test.tsx

@@ -16,6 +16,8 @@ describe("ToolCallCard", () => {
             null,
             { operation: {} },
             { operation: "add", cell_id: {} },
+            // JSON can hold an object that does not turn into text
+            JSON.parse('{"operation":"add","cell_id":{"toString":null}}'),
             { operation: "add", cell_id: "2", new_xml: {} },
             { operation: "update", cell_id: "3", new_xml: '<mxCell id="3"/>' },
         ]

tests/unit/use-diagram-tool-handlers.test.tsx

@@ -47,8 +47,9 @@ function setup(partialXml: string) {
 
 describe("the screenshot check and Stop", () => {
     const draw = async (opts: {
-        isStopped: () => boolean
+        watchStop: () => () => boolean
         validateDiagram: () => Promise<any>
+        captureValidationPng?: () => Promise<string>
     }) => {
         const onValidationStateChange = vi.fn()
         const { result } = renderHook(() =>
@@ -62,9 +63,11 @@ describe("the screenshot check and Stop", () => {
                 onFetchChart: async () => "",
                 onExport: () => {},
                 enableVlmValidation: true,
-                captureValidationPng: async () => "data:image/png;base64,AA",
+                captureValidationPng:
+                    opts.captureValidationPng ??
+                    (async () => "data:image/png;base64,AA"),
                 validateDiagram: opts.validateDiagram,
-                isStopped: opts.isStopped,
+                watchStop: opts.watchStop,
                 onValidationStateChange,
             }),
         )
@@ -89,7 +92,7 @@ describe("the screenshot check and Stop", () => {
             suggestions: [],
         }))
         const { addToolOutput, onValidationStateChange } = await draw({
-            isStopped: () => true,
+            watchStop: () => () => true,
             validateDiagram,
         })
         expect(validateDiagram).not.toHaveBeenCalled()
@@ -103,7 +106,7 @@ describe("the screenshot check and Stop", () => {
 
     it("ends with the diagram's result when Stop cancels a running check", async () => {
         const { addToolOutput, onValidationStateChange } = await draw({
-            isStopped: () => false,
+            watchStop: () => () => false,
             validateDiagram: async () => {
                 throw new DOMException("Validation cancelled", "AbortError")
             },
@@ -114,6 +117,34 @@ describe("the screenshot check and Stop", () => {
         expect(addToolOutput).toHaveBeenCalledTimes(1)
         expect(addToolOutput.mock.lastCall?.[0].state).toBeUndefined()
     })
+
+    it("skips the check when Stop came during the screenshot", async () => {
+        // As the chat panel counts it: the next message already cleared
+        // the stop flag when the screenshot arrives
+        let stops = 0
+        let stoppedNow = false
+        const validateDiagram = vi.fn(async () => ({
+            valid: true,
+            issues: [],
+            suggestions: [],
+        }))
+        const { onValidationStateChange } = await draw({
+            watchStop: () => {
+                const before = stops
+                return () => stoppedNow || stops !== before
+            },
+            captureValidationPng: async () => {
+                stops++ // Stop
+                stoppedNow = false // the next message
+                return "data:image/png;base64,AA"
+            },
+            validateDiagram,
+        })
+        expect(validateDiagram).not.toHaveBeenCalled()
+        expect(onValidationStateChange.mock.lastCall?.[1].status).toBe(
+            "skipped",
+        )
+    })
 })
 
 describe("append_diagram and the stored previews", () => {

tests/unit/use-session-manager.test.tsx

@@ -96,7 +96,7 @@ describe("saving the chat on screen", () => {
 
     it("drops a save scheduled before New Chat", async () => {
         const { result } = await setup()
-        const scheduled = result.current.getChatGeneration()
+        const scheduled = result.current.getSaveTicket()
         act(() => result.current.clearCurrentSession())
         let save!: Promise<boolean>
         act(() => {
@@ -110,7 +110,7 @@ describe("saving the chat on screen", () => {
     it("drops a save of the old chat waiting behind New Chat's save", async () => {
         const { result } = await setup()
         // The auto-save is scheduled, then New Chat saves and clears
-        const scheduled = result.current.getChatGeneration()
+        const scheduled = result.current.getSaveTicket()
         let newChatSave!: Promise<boolean>
         let autoSave!: Promise<boolean>
         act(() => {
@@ -168,3 +168,65 @@ describe("saving the chat on screen", () => {
         expect(hook.result.current.currentSessionId).toBeNull()
     })
 })
+
+describe("save tickets", () => {
+    beforeEach(() => {
+        stored.clear()
+        pendingWrites = []
+    })
+    const textOf = (session: any) => session?.messages[0].parts[0].text
+    const said = (text: string) => ({
+        ...data,
+        messages: [{ ...data.messages[0], parts: [{ type: "text", text }] }],
+    })
+
+    it("never put an older copy of a chat over a newer one", async () => {
+        const { result } = await setup()
+        let first!: Promise<boolean>
+        act(() => {
+            first = result.current.saveCurrentSession(said("first"))
+        })
+        await finishWrites()
+        await first
+        // An auto-save read its data, then waits for its thumbnail; a save
+        // without a thumbnail reads newer data and is done first
+        const older = result.current.getSaveTicket()
+        const newer = result.current.getSaveTicket()
+        let saves!: Promise<boolean[]>
+        act(() => {
+            saves = Promise.all([
+                result.current.saveCurrentSession(said("newer"), newer),
+                result.current.saveCurrentSession(said("older"), older),
+            ])
+        })
+        await finishWrites()
+        await saves
+        expect(textOf([...stored.values()][0])).toBe("newer")
+    })
+
+    it("keep a chat read before a switch out of the chat switched to", async () => {
+        stored.set("other", {
+            ...said("other chat"),
+            id: "other",
+            title: "Other",
+        })
+        const { result } = await setup()
+        // New Chat reads this chat, then waits for its thumbnail
+        const ticket = result.current.getSaveTicket()
+        // Meanwhile the user opens the other chat
+        let open!: Promise<unknown>
+        act(() => {
+            open = result.current.switchSession("other")
+        })
+        await finishWrites()
+        await open
+        let late!: Promise<boolean>
+        act(() => {
+            late = result.current.saveCurrentSession(said("this chat"), ticket)
+        })
+        await finishWrites()
+        await late
+        expect(textOf(stored.get("other"))).toBe("other chat")
+        expect(stored.size).toBe(1)
+    })
+})

tests/unit/validate-model-route.test.ts

@@ -6,7 +6,10 @@ import { POST as validateModel } from "@/app/api/validate-model/route"
 import { getAIModel } from "@/lib/ai-providers"
 
 // No saved admin providers
-vi.mock("@/lib/admin/settings", () => ({ loadSettings: () => ({}) }))
+vi.mock("@/lib/admin/settings", () => ({
+    loadSettings: () => ({}),
+    getEnvFallback: (key: string) => process.env[key] ?? null,
+}))
 
 // Every URL is public (no DNS in tests), unless a test says otherwise
 const privateUrls = vi.hoisted(() => ({ all: false }))