feat(gastown): auto-resolve merge conflicts on PRs (#2427)

apps/web/src/app/(app)/gastown/[townId]/rigs/[rigId]/settings/RigSettingsPageClient.tsx

@@ -112,6 +112,9 @@ export function RigSettingsPageClient({ townId, rigId, organizationId }: Props)
   const [autoResolvePrFeedback, setAutoResolvePrFeedback] = useState<boolean | undefined>(
     undefined
   );
+  const [autoResolveMergeConflicts, setAutoResolveMergeConflicts] = useState<boolean | undefined>(
+    undefined
+  );
   const [autoMergeDelayMinutes, setAutoMergeDelayMinutes] = useState<number | null | undefined>(
     undefined
   );
@@ -136,6 +139,7 @@ export function RigSettingsPageClient({ townId, rigId, organizationId }: Props)
       setRefineryCodeReview(cfg.code_review);
       setReviewMode(cfg.review_mode);
       setAutoResolvePrFeedback(cfg.auto_resolve_pr_feedback);
+      setAutoResolveMergeConflicts(cfg.auto_resolve_merge_conflicts);
       setAutoMergeDelayMinutes(cfg.auto_merge_delay_minutes);
       setMergeStrategy(cfg.merge_strategy);
       setConvoyMergeMode(cfg.convoy_merge_mode);
@@ -183,6 +187,7 @@ export function RigSettingsPageClient({ townId, rigId, organizationId }: Props)
         code_review: refineryCodeReview,
         review_mode: reviewMode,
         auto_resolve_pr_feedback: autoResolvePrFeedback,
+        auto_resolve_merge_conflicts: autoResolveMergeConflicts,
         auto_merge_delay_minutes: autoMergeDelayMinutes,
         merge_strategy: mergeStrategy,
         convoy_merge_mode: convoyMergeMode,
@@ -505,6 +510,46 @@ export function RigSettingsPageClient({ townId, rigId, organizationId }: Props)
                     </div>
                   </div>
 
+                  <div className="rounded-lg border border-white/[0.06] bg-white/[0.02] px-4 py-3">
+                    <div className="flex items-center gap-3">
+                      <div className="flex-1">
+                        <Label className="text-sm text-white/70">
+                          Auto-resolve merge conflicts
+                        </Label>
+                        <p className="text-[11px] text-white/30">
+                          When a PR has merge conflicts, automatically dispatch an agent to rebase
+                          and resolve them.
+                          {townCfg?.refinery?.auto_resolve_merge_conflicts !== undefined && (
+                            <span className="ml-1 text-white/20">
+                              (Town default:{' '}
+                              {townCfg.refinery.auto_resolve_merge_conflicts ? 'on' : 'off'})
+                            </span>
+                          )}
+                        </p>
+                      </div>
+                      <div className="flex items-center gap-2">
+                        {autoResolveMergeConflicts !== undefined && (
+                          <button
+                            onClick={() => setAutoResolveMergeConflicts(undefined)}
+                            className="rounded p-1 text-white/25 transition-colors hover:bg-white/[0.06] hover:text-white/50"
+                            title="Inherit from town"
+                          >
+                            <X className="size-3" />
+                          </button>
+                        )}
+                        <Switch
+                          checked={
+                            autoResolveMergeConflicts ??
+                            townCfg?.refinery?.auto_resolve_merge_conflicts ??
+                            true
+                          }
+                          onCheckedChange={v => setAutoResolveMergeConflicts(v)}
+                          className={autoResolveMergeConflicts === undefined ? 'opacity-40' : ''}
+                        />
+                      </div>
+                    </div>
+                  </div>
+
                   <div className="rounded-lg border border-white/[0.06] bg-white/[0.02] px-4 py-3">
                     <Label className="mb-1.5 block text-sm text-white/70">
                       Auto-merge delay (minutes)

apps/web/src/app/(app)/gastown/[townId]/settings/TownSettingsPageClient.tsx

@@ -279,6 +279,7 @@ export function TownSettingsPageClient({ townId, readOnly = false, organizationI
   const [refineryCodeReview, setRefineryCodeReview] = useState(true);
   const [reviewMode, setReviewMode] = useState<'rework' | 'comments'>('rework');
   const [autoResolvePrFeedback, setAutoResolvePrFeedback] = useState(false);
+  const [autoResolveMergeConflicts, setAutoResolveMergeConflicts] = useState(true);
   const [autoMergeDelayMinutes, setAutoMergeDelayMinutes] = useState<number | null>(null);
   const [mergeStrategy, setMergeStrategy] = useState<'direct' | 'pr'>('direct');
   const [stagedConvoysDefault, setStagedConvoysDefault] = useState(false);
@@ -315,6 +316,7 @@ export function TownSettingsPageClient({ townId, readOnly = false, organizationI
     setRefineryCodeReview(cfg.refinery?.code_review ?? true);
     setReviewMode(cfg.refinery?.review_mode === 'comments' ? 'comments' : 'rework');
     setAutoResolvePrFeedback(cfg.refinery?.auto_resolve_pr_feedback ?? false);
+    setAutoResolveMergeConflicts(cfg.refinery?.auto_resolve_merge_conflicts ?? true);
     setAutoMergeDelayMinutes(cfg.refinery?.auto_merge_delay_minutes ?? null);
     setMergeStrategy(cfg.merge_strategy === 'pr' ? 'pr' : 'direct');
     setStagedConvoysDefault(cfg.staged_convoys_default ?? false);
@@ -380,6 +382,7 @@ export function TownSettingsPageClient({ townId, readOnly = false, organizationI
           review_mode: reviewMode,
           require_clean_merge: true,
           auto_resolve_pr_feedback: autoResolvePrFeedback,
+          auto_resolve_merge_conflicts: autoResolveMergeConflicts,
           auto_merge_delay_minutes: autoMergeDelayMinutes,
         },
         convoy_merge_mode: convoyMergeMode,
@@ -1074,6 +1077,20 @@ export function TownSettingsPageClient({ townId, readOnly = false, organizationI
                   />
                 </div>
 
+                <div className="mt-3 flex items-center gap-3 rounded-lg border border-white/[0.06] bg-white/[0.02] px-4 py-3">
+                  <div className="flex-1">
+                    <Label className="text-sm text-white/70">Auto-resolve merge conflicts</Label>
+                    <p className="text-[11px] text-white/30">
+                      When a PR has merge conflicts, automatically dispatch an agent to rebase and
+                      resolve them.
+                    </p>
+                  </div>
+                  <Switch
+                    checked={autoResolveMergeConflicts}
+                    onCheckedChange={setAutoResolveMergeConflicts}
+                  />
+                </div>
+
                 {autoResolvePrFeedback && (
                   <div className="mt-3 rounded-lg border border-white/[0.06] bg-white/[0.02] px-4 py-3">
                     <Label className="mb-1.5 block text-sm text-white/70">Auto-merge delay</Label>

services/gastown/src/db/tables/town-events.table.ts

@@ -13,6 +13,7 @@ export const TownEventType = z.enum([
   'nudge_timeout',
   'pr_feedback_detected',
   'pr_auto_merge',
+  'pr_conflict_detected',
 ]);
 
 export type TownEventType = z.output<typeof TownEventType>;

services/gastown/src/dos/Town.do.ts

@@ -3673,6 +3673,11 @@ export class TownDO extends DurableObject<Env> {
       pendingEventCount: 0,
     };
 
+    // Fetch town config once and share across Phase 0 and Phase 1 so that
+    // applyEvent can use the full fallback chain (rig → town → default) for
+    // settings like auto_resolve_merge_conflicts.
+    const townConfig = await this.getTownConfig();
+
     // Phase 0: Drain events and apply state transitions
     try {
       const pending = events.drainEvents(this.sql);
@@ -3682,7 +3687,7 @@ export class TownDO extends DurableObject<Env> {
       }
       for (const event of pending) {
         try {
-          reconciler.applyEvent(this.sql, event);
+          reconciler.applyEvent(this.sql, event, { townConfig });
           events.markProcessed(this.sql, event.event_id);
         } catch (err) {
           logger.error('reconciler: applyEvent failed', {
@@ -3723,7 +3728,6 @@ export class TownDO extends DurableObject<Env> {
     // Phase 1: Reconcile — compute desired state vs actual state
     const sideEffects: Array<() => Promise<void>> = [];
     try {
-      const townConfig = await this.getTownConfig();
       const actions = reconciler.reconcile(this.sql, {
         draining: this._draining,
         townConfig,

services/gastown/src/dos/town/actions.ts

@@ -22,6 +22,7 @@ import * as reviewQueue from './review-queue';
 import * as patrol from './patrol';
 import { getRig } from './rigs';
 import { parseGitUrl } from '../../util/platform-pr.util';
+import type { PRStatusResult } from './town-scm';
 
 // ── Bead mutations ──────────────────────────────────────────────────
 
@@ -279,8 +280,8 @@ export type ApplyActionContext = {
   dispatchAgent: (agentId: string, beadId: string, rigId: string) => Promise<boolean>;
   /** Stop an agent's container process. */
   stopAgent: (agentId: string) => Promise<void>;
-  /** Check a PR's status via GitHub/GitLab API. Returns 'open'|'merged'|'closed'|null. */
-  checkPRStatus: (prUrl: string) => Promise<'open' | 'merged' | 'closed' | null>;
+  /** Check a PR's status via GitHub/GitLab API. Returns PRStatusResult or null. */
+  checkPRStatus: (prUrl: string) => Promise<PRStatusResult | null>;
   /** Check PR for unresolved review comments and failing CI checks. */
   checkPRFeedback: (prUrl: string) => Promise<PRFeedbackCheckResult | null>;
   /** Merge a PR via GitHub/GitLab API. */
@@ -724,8 +725,8 @@ export function applyAction(ctx: ApplyActionContext, action: Action): (() => Pro
 
       return async () => {
         try {
-          const status = await ctx.checkPRStatus(action.pr_url);
-          if (status !== null) {
+          const prStatusResult = await ctx.checkPRStatus(action.pr_url);
+          if (prStatusResult !== null) {
             // Any non-null result resets the consecutive null counter
             query(
               sql,
@@ -739,6 +740,7 @@ export function applyAction(ctx: ApplyActionContext, action: Action): (() => Pro
               `,
               [action.bead_id]
             );
+            const { status, mergeable_state } = prStatusResult;
             if (status !== 'open') {
               ctx.insertEvent('pr_status_changed', {
                 bead_id: action.bead_id,
@@ -752,6 +754,124 @@ export function applyAction(ctx: ApplyActionContext, action: Action): (() => Pro
             const refineryConfig = townConfig.refinery;
             if (!refineryConfig) return;
 
+            if (mergeable_state === 'unknown') {
+              // GitHub is still computing mergeability — skip this poll and
+              // check again on the next tick. Do NOT treat 'unknown' as clean
+              // or dirty to avoid prematurely clearing has_conflicts or
+              // emitting pr_conflict_detected before GitHub has a definitive answer.
+              return;
+            }
+
+            if (mergeable_state === 'dirty') {
+              // PR has merge conflicts — emit event ONCE per conflict episode.
+              // The reconciler decides whether to create a conflict bead or an escalation
+              // based on the rig's auto_resolve_merge_conflicts config.
+              const conflictMetaRows = z
+                .object({ has_conflicts: z.unknown() })
+                .array()
+                .parse([
+                  ...query(
+                    sql,
+                    /* sql */ `
+                      SELECT json_extract(${beads.columns.metadata}, '$.has_conflicts') AS has_conflicts
+                      FROM ${beads}
+                      WHERE ${beads.bead_id} = ?
+                    `,
+                    [action.bead_id]
+                  ),
+                ]);
+              const alreadyMarked = conflictMetaRows[0]?.has_conflicts === 1 ||
+                conflictMetaRows[0]?.has_conflicts === true;
+
+              if (!alreadyMarked) {
+                // Mark conflict on MR bead metadata
+                query(
+                  sql,
+                  /* sql */ `
+                    UPDATE ${beads}
+                    SET ${beads.columns.metadata} = json_set(
+                      COALESCE(${beads.columns.metadata}, '{}'),
+                      '$.has_conflicts', 1,
+                      '$.conflicts_detected_at', ?
+                    ),
+                    ${beads.columns.updated_at} = ?
+                    WHERE ${beads.bead_id} = ?
+                  `,
+                  [now(), now(), action.bead_id]
+                );
+
+                // Get MR bead source bead ID and branch for the event payload
+                const mrMetaRows = z
+                  .object({ source_bead_id: z.string().nullable(), branch: z.string().nullable() })
+                  .array()
+                  .parse([
+                    ...query(
+                      sql,
+                      /* sql */ `
+                        SELECT
+                          json_extract(${beads.columns.metadata}, '$.source_bead_id') AS source_bead_id,
+                          ${review_metadata.columns.branch} AS branch
+                        FROM ${beads}
+                        INNER JOIN ${review_metadata} ON ${review_metadata.bead_id} = ${beads.bead_id}
+                        WHERE ${beads.bead_id} = ?
+                      `,
+                      [action.bead_id]
+                    ),
+                  ]);
+                const sourceBead = mrMetaRows[0]?.source_bead_id ?? null;
+                const conflictBranch = mrMetaRows[0]?.branch ?? '';
+
+                ctx.insertEvent('pr_conflict_detected', {
+                  bead_id: action.bead_id,
+                  payload: {
+                    mr_bead_id: action.bead_id,
+                    source_bead_id: sourceBead,
+                    pr_url: action.pr_url,
+                    branch: conflictBranch,
+                  },
+                });
+              }
+
+              // A dirty PR must not proceed to the auto-merge timer — reset the
+              // grace-period clock so the timer starts fresh once conflicts are resolved.
+              query(
+                sql,
+                /* sql */ `
+                  UPDATE ${review_metadata}
+                  SET ${review_metadata.columns.auto_merge_ready_since} = NULL
+                  WHERE ${review_metadata.bead_id} = ?
+                    AND ${review_metadata.columns.auto_merge_ready_since} IS NOT NULL
+                `,
+                [action.bead_id]
+              );
+              return;
+            } else if (
+              mergeable_state === 'clean' ||
+              mergeable_state === 'blocked' ||
+              mergeable_state === 'has_hooks'
+            ) {
+              // Conflict definitively resolved — clear the has_conflicts flag.
+              // 'clean': no conflicts, all checks pass.
+              // 'blocked': no conflicts but checks are failing (e.g. required reviews).
+              // 'has_hooks': no conflicts but pre-receive hooks are pending.
+              // 'unknown' is handled above (GitHub still computing — retry next poll).
+              query(
+                sql,
+                /* sql */ `
+                  UPDATE ${beads}
+                  SET ${beads.columns.metadata} = json_remove(
+                    COALESCE(${beads.columns.metadata}, '{}'),
+                    '$.has_conflicts',
+                    '$.conflicts_detected_at'
+                  ),
+                  ${beads.columns.updated_at} = ?
+                  WHERE ${beads.bead_id} = ?
+                    AND json_extract(${beads.columns.metadata}, '$.has_conflicts') IS NOT NULL
+                `,
+                [now(), action.bead_id]
+              );
+            }
+
             const wantsAutoResolve = refineryConfig.auto_resolve_pr_feedback === true;
             const wantsAutoMerge =
               refineryConfig.auto_merge !== false &&
@@ -777,10 +897,10 @@ export function applyAction(ctx: ApplyActionContext, action: Action): (() => Pro
               // If the PR was merged externally during that window, inserting
               // pr_feedback_detected would create a feedback bead for a merged
               // PR — leading to a duplicate PR on an already-merged branch.
-              const freshStatus = await ctx.checkPRStatus(action.pr_url);
-              if (freshStatus !== 'open') {
+              const freshStatusResult = await ctx.checkPRStatus(action.pr_url);
+              if (freshStatusResult?.status !== 'open') {
                 console.log(
-                  `${LOG} poll_pr: PR status changed to '${freshStatus}' during feedback check, skipping feedback for bead=${action.bead_id}`
+                  `${LOG} poll_pr: PR status changed to '${freshStatusResult?.status ?? 'null'}' during feedback check, skipping feedback for bead=${action.bead_id}`
                 );
               } else {
                 const existingFeedback = hasExistingFeedbackBead(sql, action.bead_id);

services/gastown/src/dos/town/agents.ts

@@ -519,13 +519,41 @@ export function prime(sql: SqlStorage, agentId: string): PrimeContext {
     };
   }
 
+  // Build PR conflict context if the hooked bead is a PR conflict resolution request,
+  // or if it is a PR feedback bead that has also accumulated merge conflicts.
+  let pr_conflict_context: PrimeContext['pr_conflict_context'] = null;
+  if (hookedBead?.labels.includes('gt:pr-conflict') && hookedBead.metadata) {
+    const meta = hookedBead.metadata as Record<string, unknown>;
+    pr_conflict_context = {
+      pr_url: typeof meta.pr_url === 'string' ? meta.pr_url : null,
+      branch: typeof meta.branch === 'string' ? meta.branch : null,
+      target_branch: typeof meta.target_branch === 'string' ? meta.target_branch : null,
+      has_feedback: meta.has_feedback === true || meta.has_feedback === 1,
+    };
+  } else if (hookedBead?.labels.includes('gt:pr-feedback') && hookedBead.metadata) {
+    // A feedback bead can also have has_conflicts: true when a conflict was detected
+    // after the feedback bead was already created. Surface the conflict context so the
+    // agent resolves conflicts first, then addresses review feedback.
+    const meta = hookedBead.metadata as Record<string, unknown>;
+    if (meta.has_conflicts === true || meta.has_conflicts === 1) {
+      pr_conflict_context = {
+        pr_url: typeof meta.pr_url === 'string' ? meta.pr_url : null,
+        branch: typeof meta.branch === 'string' ? meta.branch : null,
+        target_branch:
+          typeof meta.conflict_target_branch === 'string' ? meta.conflict_target_branch : null,
+        has_feedback: true,
+      };
+    }
+  }
+
   return {
     agent,
     hooked_bead: hookedBead,
     undelivered_mail: undeliveredMail,
     open_beads: openBeads,
     rework_context,
     pr_fixup_context,
+    pr_conflict_context,
   };
 }