fix(poteto-mode): observe current base branch targets

plugins/pstack/skills/poteto-mode/scripts/watch-pr/fakes.test-helper.ts

@@ -1,3 +1,3 @@
 import type {
   Check,
   ChecksFastPath,
@@ -98,11 +98,15 @@
     async pullRequest(requested) {
       calls.push("pullRequest");
       reads += 1;
+      const facts = {
+        ...defaults,
+        ...options.facts,
+        ...(reads > 1 ? options.factsOnReread : {}),
+      };
       return parsePullRequest(
         {
-          ...defaults,
-          ...options.facts,
-          ...(reads > 1 ? options.factsOnReread : {}),
+          ...facts,
+          baseRef: { target: { oid: facts.baseRefOid } },
         },
         requested
       );

plugins/pstack/skills/poteto-mode/scripts/watch-pr/github.test.ts

@@ -1,3 +1,3 @@
 import { describe, expect, it } from "bun:test";
 import { WatchDeadline } from "./deadline.ts";
 import {
@@ -9,6 +9,7 @@
   parseFastCheck,
   parsePullRequest,
   parseReviewThreads,
+  PR_FACTS_QUERY,
   resolveChecks,
   resolveContext,
   runJson,
@@ -299,7 +300,7 @@
     mergeStateStatus: "CLEAN",
     reviewDecision: "APPROVED",
     headRefOid: "head",
-    baseRefOid: "base",
+    baseRef: { target: { oid: "base" } },
     headRefName: "feature",
     baseRefName: "main",
     state: "OPEN",
@@ -316,11 +317,10 @@
     ).toBe("CONFLICTING");
   });
 
-  it("reads gh's empty reviewDecision as no decision rather than a parse failure", () => {
-    expect(
+  it("rejects an empty reviewDecision like any other unknown enum value", () => {
+    expect(() =>
       parsePullRequest({ ...rawPullRequest, reviewDecision: "" }, context)
-        .reviewDecision
-    ).toBeNull();
+    ).toThrow(WatcherQueryError);
   });
 
   it("still rejects an unknown reviewDecision", () => {
@@ -329,6 +329,32 @@
     ).toThrow(WatcherQueryError);
   });
 
+  it("uses the current base target when the scalar base OID is stale", () => {
+    expect(
+      parsePullRequest(
+        {
+          ...rawPullRequest,
+          baseRefOid: "stale-base",
+          baseRef: { target: { oid: "current-base" } },
+        },
+        context
+      ).baseRefOid
+    ).toBe("current-base");
+  });
+
+  it("queries the current base target with the other PR facts", () => {
+    expect(PR_FACTS_QUERY).toContain("baseRef { target { oid } }");
+    expect(PR_FACTS_QUERY).not.toContain("baseRefOid");
+  });
+
+  it("fails closed when the current base ref is null or missing", () => {
+    const missingBaseRef = Object.fromEntries(
+      Object.entries(rawPullRequest).filter(([key]) => key !== "baseRef")
+    );
+    for (const value of [{ ...rawPullRequest, baseRef: null }, missingBaseRef])
+      expect(() => parsePullRequest(value, context)).toThrow(WatcherQueryError);
+  });
+
   it("rejects unknown enum values as retryable errors carrying the raw value", () => {
     try {
       parsePullRequest(
@@ -406,7 +432,9 @@
       },
     },
   };
-  const threads = parseReviewThreads(response);
+  const threads = parseReviewThreads(
+    response.data.repository.pullRequest.reviewThreads.nodes
+  );
   expect(threads).toHaveLength(2);
   expect(threads.map((thread) => thread.isBugbot)).toEqual([true, true]);
   expect(threads.map((thread) => thread.bugbotReviewPasses)).toEqual([3, 3]);

plugins/pstack/skills/poteto-mode/scripts/watch-pr/github.ts

@@ -1,4 +1,4 @@
-import { parseLandingRevision } from "./landing.ts";
+import { baseRefTargetOid, text } from "./landing.ts";
 import { spawn } from "node:child_process";
 import { DeadlineExceeded, type WatchDeadline } from "./deadline.ts";
 import type * as T from "./types.ts";
@@ -21,6 +21,22 @@
 }`;
 export const PR_COMMIT_STATUS_QUERY =
   "\nquery PrCommitStatuses($owner: String!, $repo: String!, $pr: Int!) {\n  repository(owner: $owner, name: $repo) {\n    pullRequest(number: $pr) {\n      commits(last: 50) {\n        nodes {\n          commit {\n            oid\n            statusCheckRollup {\n              state\n            }\n          }\n        }\n      }\n    }\n  }\n}\n";
+export const PR_FACTS_QUERY = `query PullRequestFacts($owner: String!, $repo: String!, $pr: Int!) {
+  repository(owner: $owner, name: $repo) {
+    pullRequest(number: $pr) {
+      mergeable
+      mergeStateStatus
+      reviewDecision
+      headRefOid
+      headRefName
+      baseRefName
+      baseRef { target { oid } }
+      state
+      mergedAt
+      isDraft
+    }
+  }
+}`;
 export const PR_CHECK_ROLLUP_QUERY =
   "\nquery PrCheckRollup($owner: String!, $repo: String!, $pr: Int!, $after: String) {\n  repository(owner: $owner, name: $repo) {\n    pullRequest(number: $pr) {\n      commits(last: 1) {\n        nodes {\n          commit {\n            statusCheckRollup {\n              contexts(first: 100, after: $after) {\n                pageInfo {\n                  hasNextPage\n                  endCursor\n                }\n                nodes {\n                  __typename\n                  ... on CheckRun {\n                    name\n                    status\n                    conclusion\n                    detailsUrl\n                  }\n                  ... on StatusContext {\n                    context\n                    state\n                    targetUrl\n                  }\n                }\n              }\n            }\n          }\n        }\n      }\n    }\n  }\n}\n";
 
@@ -205,15 +221,8 @@
   "CHANGES_REQUESTED",
   "REVIEW_REQUIRED",
 ] as const;
-// `gh pr view` reports no review decision as "", not null. Only this field does
-// it, so the normalization stays here rather than in nullableEnum, where it
-// would stop a genuinely unexpected rollup state from failing closed.
 const reviewDecision = (value: unknown): T.ReviewDecision =>
-  nullableEnum(
-    value === "" ? null : value,
-    REVIEW_DECISIONS,
-    "pull request.reviewDecision"
-  );
+  nullableEnum(value, REVIEW_DECISIONS, "pull request.reviewDecision");
 function parseRemote(value: string): T.Repository | null {
   let normalized = value.trim();
   if (normalized.startsWith("git@github.com:"))
@@ -422,11 +431,9 @@
   }
   return null;
 }
-export function parseReviewThreads(value: unknown): readonly T.ReviewThread[] {
-  const nodes = list(
-    at(value, ["data", "repository", "pullRequest", "reviewThreads", "nodes"]),
-    "reviewThreads.nodes"
-  );
+export function parseReviewThreads(
+  nodes: readonly unknown[]
+): readonly T.ReviewThread[] {
   const threads: {
     readonly id: string;
     readonly firstComment: T.ReviewComment | null;
@@ -485,7 +492,7 @@
     ),
     reviewDecision: reviewDecision(object.reviewDecision),
     headRefOid: optionalString(object.headRefOid, "pull request.headRefOid"),
-    baseRefOid: optionalString(object.baseRefOid, "pull request.baseRefOid"),
+    baseRefOid: baseRefTargetOid(object.baseRef),
     headRefName: string(object.headRefName, "pull request.headRefName"),
     baseRefName: string(object.baseRefName, "pull request.baseRefName"),
     state: enumValue(
@@ -497,7 +504,13 @@
     isDraft: object.isDraft,
   };
   return facts.state === "OPEN"
-    ? { ...facts, ...parseLandingRevision(object, context), state: facts.state }
+    ? {
+        ...facts,
+        state: facts.state,
+        headRefOid: text(facts.headRefOid, "headRefOid"),
+        baseRefName: text(facts.baseRefName, "baseRefName"),
+        baseRefOid: text(facts.baseRefOid, "baseRefOid"),
+      }
     : { ...facts, state: facts.state };
 }
 function graphqlArgs(
@@ -542,18 +555,24 @@
       number: pr ?? parsePrNumber(object.number, "current PR.number"),
     };
   }
+  private async graphql(
+    query: string,
+    context: T.PrContext,
+    after: string | null = null
+  ): Promise<Record<string, unknown>> {
+    const argv = graphqlArgs(query, context);
+    if (after !== null) argv.push("-f", `after=${after}`);
+    const response = record(await this.runJson(argv), "GraphQL response");
+    if (response.errors !== undefined)
+      missing("GraphQL errors", response.errors);
+    return record(
+      at(response, ["data", "repository", "pullRequest"]),
+      "data.repository.pullRequest"
+    );
+  }
   async pullRequest(context: T.PrContext): Promise<T.PullRequestFacts> {
     return parsePullRequest(
-      await this.runJson([
-        "gh",
-        "pr",
-        "view",
-        String(context.number),
-        "--repo",
-        `${context.owner}/${context.repo}`,
-        "--json",
-        "mergeable,mergeStateStatus,reviewDecision,headRefOid,headRefName,baseRefName,baseRefOid,state,mergedAt,isDraft",
-      ]),
+      await this.graphql(PR_FACTS_QUERY, context),
       context
     );
   }
@@ -650,11 +669,13 @@
     context: T.PrContext,
     after: string | null
   ): Promise<T.RollupPage> {
-    const argv = graphqlArgs(PR_CHECK_ROLLUP_QUERY, context);
-    if (after !== null) argv.push("-f", `after=${after}`);
-    const value = await this.runJson(argv);
+    const pullRequest = await this.graphql(
+      PR_CHECK_ROLLUP_QUERY,
+      context,
+      after
+    );
     const commits = list(
-      at(value, ["data", "repository", "pullRequest", "commits", "nodes"]),
+      at(pullRequest, ["commits", "nodes"]),
       "commits.nodes"
     );
     if (commits.length === 0)
@@ -691,13 +712,12 @@
     const cursors = new Set<string>();
     let after: string | null = null;
     do {
-      const argv = graphqlArgs(REVIEW_THREADS_QUERY, context);
-      if (after !== null) argv.push("-f", `after=${after}`);
-      const value = await this.runJson(argv);
-      const connection = record(
-        at(value, ["data", "repository", "pullRequest", "reviewThreads"]),
-        "reviewThreads"
+      const pullRequest = await this.graphql(
+        REVIEW_THREADS_QUERY,
+        context,
+        after
       );
+      const connection = record(pullRequest.reviewThreads, "reviewThreads");
       nodes.push(...list(connection.nodes, "reviewThreads.nodes"));
       const page = record(connection.pageInfo, "reviewThreads.pageInfo");
       if (typeof page.hasNextPage !== "boolean")
@@ -711,18 +731,14 @@
         cursors.add(after);
       }
     } while (after !== null);
-    return parseReviewThreads({
-      data: { repository: { pullRequest: { reviewThreads: { nodes } } } },
-    });
+    return parseReviewThreads(nodes);
   }
   async commitRollups(
     context: T.PrContext
   ): Promise<readonly T.CommitRollup[]> {
-    const value = await this.runJson(
-      graphqlArgs(PR_COMMIT_STATUS_QUERY, context)
-    );
+    const pullRequest = await this.graphql(PR_COMMIT_STATUS_QUERY, context);
     const commits = list(
-      at(value, ["data", "repository", "pullRequest", "commits", "nodes"]),
+      at(pullRequest, ["commits", "nodes"]),
       "commits.nodes"
     );
     return commits.map((item, index) => {

plugins/pstack/skills/poteto-mode/scripts/watch-pr/integrity.test.ts

@@ -47,7 +47,7 @@ describe("commit identity", () => {
     mergeStateStatus: "CLEAN",
     reviewDecision: "APPROVED",
     headRefOid: "head",
-    baseRefOid: "base",
+    baseRef: { target: { oid: "base" } },
     headRefName: "feature",
     baseRefName: "main",
     state: "OPEN",
@@ -56,7 +56,10 @@ describe("commit identity", () => {
   };
 
   it("rejects an open PR without a head or base commit where it is parsed", () => {
-    for (const missing of [{ headRefOid: null }, { baseRefOid: "" }])
+    for (const missing of [
+      { headRefOid: null },
+      { baseRef: { target: { oid: "" } } },
+    ])
       expect(() =>
         parsePullRequest({ ...rawPullRequest, ...missing }, context)
       ).toThrow(WatcherQueryError);
@@ -70,7 +73,7 @@ describe("commit identity", () => {
           state: "MERGED",
           mergedAt: "2026-07-26T00:00:00Z",
           headRefOid: null,
-          baseRefOid: null,
+          baseRef: null,
         },
         context
       )
@@ -135,6 +138,28 @@ describe("commit identity", () => {
     );
   });
 
+  it("detects current base movement when the PR's scalar base OID stays stale", async () => {
+    const base = fakeReader();
+    let reads = 0;
+    const reader = {
+      ...base,
+      async pullRequest(requested: typeof context) {
+        const baseRefOid = reads++ === 0 ? "base" : "advanced";
+        return parsePullRequest(
+          {
+            ...rawPullRequest,
+            baseRefOid: "stale-base",
+            baseRef: { target: { oid: baseRefOid } },
+          },
+          requested
+        );
+      },
+    };
+    await expect(readSnapshot({ ...snapshotArgs, reader })).rejects.toThrow(
+      "PR changed while collecting"
+    );
+  });
+
   it("cannot report ready when the destination query is unavailable", async () => {
     const base = fakeReader();
     let reads = 0;
@@ -809,10 +834,11 @@ describe("landing validators", () => {
     [
       "parseLandingRevision",
       () =>
-        parseLandingRevision(
-          { headRefOid: "head", baseRefName: "main" },
-          context
-        ),
+        parseLandingRevision({
+          context,
+          headRefOid: "head",
+          baseRefName: "main",
+        }),
       "baseRefOid must be a non-empty string",
     ],
   ] as const)
@@ -842,7 +868,7 @@ describe("landing validators", () => {
             mergeStateStatus: "CLEAN",
             reviewDecision: "APPROVED",
             headRefOid: null,
-            baseRefOid: "base",
+            baseRef: { target: { oid: "base" } },
             headRefName: "feature",
             baseRefName: "main",
             state: "OPEN",

plugins/pstack/skills/poteto-mode/scripts/watch-pr/landing.ts

@@ -27,6 +27,14 @@ export function text(value: unknown, label: string): string {
 export const nullableText = (value: unknown, label: string): string | null =>
   value === null ? null : text(value, label);
 
+export function baseRefTargetOid(value: unknown): string | null {
+  if (value === null) return null;
+  const baseRef = object(value, "baseRef");
+  if (baseRef.target === null) return null;
+  const target = object(baseRef.target, "baseRef.target");
+  return nullableText(target.oid, "baseRef.target.oid");
+}
+
 export function oneOf<const V extends readonly string[]>(
   value: unknown,
   values: V,
@@ -50,13 +58,10 @@ export function parseContext(value: unknown): PrContext {
   return { owner, repo, number: parsePrNumber(fields.number) };
 }
 
-export function parseLandingRevision(
-  value: unknown,
-  context?: PrContext
-): LandingRevision {
+export function parseLandingRevision(value: unknown): LandingRevision {
   const fields = object(value, "landing revision");
   return {
-    context: context ?? parseContext(fields.context),
+    context: parseContext(fields.context),
     headRefOid: text(fields.headRefOid, "headRefOid"),
     baseRefName: text(fields.baseRefName, "baseRefName"),
     baseRefOid: text(fields.baseRefOid, "baseRefOid"),