feat(FN-4763): complete Step 1 — capture PR mergeable state

Fusion-Task-Id: FN-4763
Fusion-Task-Lineage: b3628e63-682b-4a39-9a7d-2c96278c5366

packages/dashboard/src/__tests__/github.test.ts

@@ -1105,6 +1105,8 @@ describe("GitHubClient", () => {
           title: "Ready PR",
           state: "OPEN",
           reviewDecision: "APPROVED",
+          mergeable: "MERGEABLE",
+          mergeStateStatus: "CLEAN",
           baseRefName: "main",
           headRefName: "fusion/fn-093",
         })
@@ -1116,6 +1118,8 @@ describe("GitHubClient", () => {
       const result = await client.getPrMergeStatus("owner", "repo", 42);
 
       expect(result.mergeReady).toBe(true);
+      expect(result.mergeable).toBe("clean");
+      expect(result.prInfo.mergeable).toBe("clean");
       expect(result.blockingReasons).toEqual([]);
       expect(result.checks).toEqual([
         {
@@ -1130,6 +1134,44 @@ describe("GitHubClient", () => {
       ]);
     });
 
+    it("maps DIRTY merge-state to conflicting even when mergeable is unknown", async () => {
+      mockRunGhJsonAsync
+        .mockResolvedValueOnce({
+          number: 42,
+          url: "https://github.com/owner/repo/pull/42",
+          title: "Dirty PR",
+          state: "OPEN",
+          reviewDecision: "APPROVED",
+          mergeable: "UNKNOWN",
+          mergeStateStatus: "DIRTY",
+          baseRefName: "main",
+          headRefName: "fusion/fn-093",
+        })
+        .mockResolvedValueOnce([{ name: "ci", state: "SUCCESS" }]);
+
+      const result = await client.getPrMergeStatus("owner", "repo", 42);
+      expect(result.mergeable).toBe("conflicting");
+      expect(result.prInfo.mergeable).toBe("conflicting");
+    });
+
+    it("maps missing mergeability fields to unknown", async () => {
+      mockRunGhJsonAsync
+        .mockResolvedValueOnce({
+          number: 42,
+          url: "https://github.com/owner/repo/pull/42",
+          title: "Unknown PR",
+          state: "OPEN",
+          reviewDecision: "APPROVED",
+          baseRefName: "main",
+          headRefName: "fusion/fn-093",
+        })
+        .mockResolvedValueOnce([{ name: "ci", state: "SUCCESS" }]);
+
+      const result = await client.getPrMergeStatus("owner", "repo", 42);
+      expect(result.mergeable).toBe("unknown");
+      expect(result.prInfo.mergeable).toBe("unknown");
+    });
+
     it("falls back to GraphQL API when gh CLI merge-status lookup fails and token is available", async () => {
       mockRunGhJsonAsync.mockRejectedValue(new Error("gh failed"));
       const clientWithToken = new GitHubClient("ghp_token");
@@ -1144,6 +1186,8 @@ describe("GitHubClient", () => {
                 title: "Fallback PR",
                 state: "OPEN",
                 reviewDecision: null,
+                mergeable: "CONFLICTING",
+                mergeStateStatus: "DIRTY",
                 baseRefName: "main",
                 headRefName: "fusion/fn-093",
                 comments: { totalCount: 0 },
@@ -1196,6 +1240,8 @@ describe("GitHubClient", () => {
       const result = await clientWithToken.getPrMergeStatus("owner", "repo", 42);
 
       expect(result.mergeReady).toBe(true);
+      expect(result.mergeable).toBe("conflicting");
+      expect(result.prInfo.mergeable).toBe("conflicting");
       expect(result.checks).toEqual([
         {
           name: "ci",

packages/dashboard/src/github.ts

@@ -1,4 +1,4 @@
-import type { IssueInfo, PrInfo, TaskReviewData, TaskReviewItem, TaskReviewSummary } from "@fusion/core";
+import type { IssueInfo, PrConflictState, PrInfo, TaskReviewData, TaskReviewItem, TaskReviewSummary } from "@fusion/core";
 import {
   isGhAvailable,
   isGhAuthenticated,
@@ -156,6 +156,7 @@ export interface PrMergeStatus {
   prInfo: PrInfo;
   reviewDecision: ReviewDecision;
   checks: PrCheckStatus[];
+  mergeable: PrConflictState;
   mergeReady: boolean;
   blockingReasons: string[];
 }
@@ -197,6 +198,9 @@ interface GhReviewJson {
   url?: string | null;
 }
 
+type GhPrMergeable = "MERGEABLE" | "CONFLICTING" | "UNKNOWN";
+type GhPrMergeStateStatus = "CLEAN" | "DIRTY" | "BLOCKED" | "BEHIND" | "UNSTABLE" | "UNKNOWN" | "HAS_HOOKS";
+
 interface GhPrViewJson {
   id?: string;
   number: number;
@@ -205,6 +209,8 @@ interface GhPrViewJson {
   state: "OPEN" | "CLOSED" | "MERGED";
   isDraft?: boolean;
   reviewDecision?: ReviewDecision;
+  mergeable?: GhPrMergeable;
+  mergeStateStatus?: GhPrMergeStateStatus;
   baseRefName: string;
   headRefName: string;
   comments: Array<{
@@ -337,6 +343,25 @@ function normalizeCheckState(state: string | null | undefined): PrCheckState {
   }
 }
 
+function mapPrConflictState(
+  mergeable?: GhPrMergeable,
+  mergeStateStatus?: GhPrMergeStateStatus,
+): PrConflictState {
+  if (mergeStateStatus === "DIRTY" || mergeable === "CONFLICTING") {
+    return "conflicting";
+  }
+  if (mergeStateStatus === "BEHIND") {
+    return "behind";
+  }
+  if (mergeStateStatus === "BLOCKED") {
+    return "blocked";
+  }
+  if (mergeStateStatus === "CLEAN" || mergeable === "MERGEABLE") {
+    return "clean";
+  }
+  return "unknown";
+}
+
 function toPrInfo(input: {
   url: string;
   number: number;
@@ -346,6 +371,7 @@ function toPrInfo(input: {
   baseBranch: string;
   isDraft?: boolean;
   commentCount?: number;
+  mergeable?: PrConflictState;
   lastCommentAt?: string;
   lastCheckedAt?: string;
 }): PrInfo {
@@ -359,6 +385,7 @@ function toPrInfo(input: {
     commentCount: input.commentCount ?? 0,
     isDraft: input.isDraft,
     draft: input.isDraft,
+    mergeable: input.mergeable,
     lastCommentAt: input.lastCommentAt,
     lastCheckedAt: input.lastCheckedAt,
   };
@@ -1017,8 +1044,9 @@ export class GitHubClient {
     const pr = await runGhJsonAsync<GhPrViewJson>([
       "pr", "view", String(number),
       "--repo", `${resolved.owner}/${resolved.repo}`,
-      "--json", "number,url,title,state,isDraft,baseRefName,headRefName,reviewDecision",
+      "--json", "number,url,title,state,isDraft,baseRefName,headRefName,reviewDecision,mergeable,mergeStateStatus",
     ]);
+    const mergeable = mapPrConflictState(pr.mergeable, pr.mergeStateStatus);
     const checks = await runGhJsonAsync<GhPrCheckJson[]>([
       "pr", "checks", String(number),
       "--repo", `${resolved.owner}/${resolved.repo}`,
@@ -1035,6 +1063,7 @@ export class GitHubClient {
       baseBranch: pr.baseRefName,
       isDraft: pr.isDraft,
       commentCount: 0,
+      mergeable,
     });
     const normalizedChecks = checks.map((check) => ({
       name: check.name,
@@ -1054,6 +1083,7 @@ export class GitHubClient {
       prInfo,
       reviewDecision: pr.reviewDecision ?? null,
       checks: normalizedChecks,
+      mergeable,
       mergeReady: readiness.ready,
       blockingReasons: readiness.blockingReasons,
     };
@@ -1073,6 +1103,8 @@ export class GitHubClient {
               title
               state
               reviewDecision
+              mergeable
+              mergeStateStatus
               isDraft
               baseRefName
               headRefName
@@ -1121,6 +1153,8 @@ export class GitHubClient {
             title: string;
             state: "OPEN" | "CLOSED" | "MERGED";
             reviewDecision: ReviewDecision;
+            mergeable?: GhPrMergeable;
+            mergeStateStatus?: GhPrMergeStateStatus;
             isDraft?: boolean;
             baseRefName: string;
             headRefName: string;
@@ -1186,6 +1220,7 @@ export class GitHubClient {
       } satisfies PrCheckStatus];
     });
 
+    const mergeable = mapPrConflictState(pr.mergeable, pr.mergeStateStatus);
     const prInfo = toPrInfo({
       url: pr.url,
       number: pr.number,
@@ -1195,6 +1230,7 @@ export class GitHubClient {
       baseBranch: pr.baseRefName,
       isDraft: pr.isDraft,
       commentCount: pr.comments.totalCount,
+      mergeable,
     });
     const readiness = isPrMergeReady({
       status: prInfo.status,
@@ -1206,6 +1242,7 @@ export class GitHubClient {
       prInfo,
       reviewDecision: pr.reviewDecision,
       checks,
+      mergeable,
       mergeReady: readiness.ready,
       blockingReasons: readiness.blockingReasons,
     };