From 3d44b392b314baa4cb5e02cd143ae0cd9ae7a9bb Mon Sep 17 00:00:00 2001
From: Seongmin Lee <git@boltless.me>
Date: Thu, 20 Aug 2026 01:53:46 +0900
Subject: [PATCH] web: render PR with no submissions

Signed-off-by: Seongmin Lee <git@boltless.me>
---
 web/src/lib/api/pullRoute.test.ts             |   9 ++
 web/src/lib/api/pullRoute.ts                  |  10 +-
 .../[handle]/[repo]/pulls/[aturi]/+layout.ts  |   2 -
 .../[repo]/pulls/[aturi]/[version]/+layout.ts |   3 +-
 .../[aturi]/[version]/[[range]]/+page.svelte  | 105 ++++++++++++------
 .../[aturi]/[version]/[[range]]/+page.ts      |   6 +-
 6 files changed, 90 insertions(+), 45 deletions(-)

diff --git a/web/src/lib/api/pullRoute.test.ts b/web/src/lib/api/pullRoute.test.ts
index e10850ffe..656ffde45 100644
--- a/web/src/lib/api/pullRoute.test.ts
+++ b/web/src/lib/api/pullRoute.test.ts
@@ -51,6 +51,15 @@ describe("parseDiffRoute", () => {
 		expect(view("1", "base..head")).toMatchObject({ base: "b1", head: "h1" });
 	});
 
+	it("resolves an empty version list instead of bouncing latest back to itself", () => {
+		expect(parseDiffRoute([], "latest")).toEqual({
+			mode: "diff",
+			version: 0,
+			base: "",
+			head: ""
+		});
+	});
+
 	it("redirects a bad version to latest and a bad range to the version", () => {
 		expect(parseDiffRoute(versions, "9")).toEqual({ redirect: "latest" });
 		expect(parseDiffRoute(versions, "foo")).toEqual({ redirect: "latest" });
diff --git a/web/src/lib/api/pullRoute.ts b/web/src/lib/api/pullRoute.ts
index 3d5770414..a2b8e14c3 100644
--- a/web/src/lib/api/pullRoute.ts
+++ b/web/src/lib/api/pullRoute.ts
@@ -86,8 +86,10 @@ export const parseDiffRoute = (
 	rangeParam?: string
 ): PullDiffView | PullRouteRedirect => {
 	const version =
-		versionParam === "latest" ? versions.length - 1 : index(versionParam, versions.length);
-	if (version === null || version < 0) return { redirect: "latest" };
+		versionParam === "latest"
+			? Math.max(versions.length - 1, 0)
+			: index(versionParam, versions.length);
+	if (version === null) return { redirect: "latest" };
 
 	const spec = parseRange(rangeParam ?? "");
 	if (!spec) return { redirect: "version" };
@@ -97,7 +99,7 @@ export const parseDiffRoute = (
 	return {
 		mode: "diff",
 		version,
-		base: isDiffBase ? versions[version].base : spec.base,
-		head: isDiffHead ? versions[version].head : spec.head
+		base: isDiffBase ? (versions[version]?.base ?? "") : spec.base,
+		head: isDiffHead ? (versions[version]?.head ?? "") : spec.head
 	};
 };
diff --git a/web/src/routes/[handle]/[repo]/pulls/[aturi]/+layout.ts b/web/src/routes/[handle]/[repo]/pulls/[aturi]/+layout.ts
index 449803bf3..f19e8e38f 100644
--- a/web/src/routes/[handle]/[repo]/pulls/[aturi]/+layout.ts
+++ b/web/src/routes/[handle]/[repo]/pulls/[aturi]/+layout.ts
@@ -42,8 +42,6 @@ export const load: LayoutLoad = async (event) => {
 	// const pullVersions = listPullVersions(aturi)
 
 	if (!pullView) error(404, "Pull request not found");
-	if (!pullView.versions.length)
-		error(404, "This pull request has no ref-based versions to show");
 
 	const body = pullView.body?.text ?? "";
 	const bodyHtml = body ? await renderMarkup(body, markup).catch(() => null) : null;
diff --git a/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/+layout.ts b/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/+layout.ts
index 4fc545d75..c48bc02f9 100644
--- a/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/+layout.ts
+++ b/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/+layout.ts
@@ -24,7 +24,8 @@ export const load: LayoutLoad = async (event) => {
 	});
 
 	// TODO: bobbin should hydrate the commit list with backlinked comment counts
-	const commits = await listLog(ctx, sourceRepoDid as Did, pull.versions[route.version]);
+	const version = pull.versions[route.version];
+	const commits = version ? await listLog(ctx, sourceRepoDid as Did, version) : [];
 	const commentCounts = countCommentsByCommit(parent.comments);
 
 	return {
diff --git a/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.svelte b/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.svelte
index c0c83aaf8..b9d2f1e1f 100644
--- a/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.svelte
+++ b/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.svelte
@@ -383,47 +383,80 @@
 			</Ticket>
 			<!-- TODO: labels -->
 		</TabPanel>
-		<!-- PR Commits -->
-		<div class="space-y-2 rounded border border-border-default bg-background-default p-4">
-			<PullCommitListHeader
-				versions={pull.versions}
-				{commits}
-				{versionRange}
-				oncommitVersions={confirmVersions}
-			>
-				{#snippet actions()}
-					{#if isAuthor && pullState === "open" && sourceBranch}
+		{#if pull.versions.length}
+			<!-- PR Commits -->
+			<div class="space-y-2 rounded border border-border-default bg-background-default p-4">
+				<PullCommitListHeader
+					versions={pull.versions}
+					{commits}
+					{versionRange}
+					oncommitVersions={confirmVersions}
+				>
+					{#snippet actions()}
+						{#if isAuthor && pullState === "open" && sourceBranch}
+							<Button
+								icon={IterationCcw}
+								title={canResubmit
+									? "Resubmit pull request"
+									: "Update the source branch to resubmit this pull request"}
+								disabled={!canResubmit || resubmit.loading}
+								loading={resubmit.loading}
+								onclick={() => resubmit.run()}
+							>
+								Resubmit
+							</Button>
+						{/if}
 						<Button
-							icon={IterationCcw}
-							title={canResubmit
-								? "Resubmit pull request"
-								: "Update the source branch to resubmit this pull request"}
-							disabled={!canResubmit || resubmit.loading}
-							loading={resubmit.loading}
-							onclick={() => resubmit.run()}
+							icon={Workflow}
+							title="Approve CI run from this pull request"
+							disabled
 						>
-							Resubmit
+							Approve CI
 						</Button>
-					{/if}
-					<Button icon={Workflow} title="Approve CI run from this pull request" disabled>
-						Approve CI
+					{/snippet}
+				</PullCommitListHeader>
+				<ErrorAlert label={resubmit.error} />
+				{#if isInterdiff}
+					<PullCommitListInterdiff
+						{commits}
+						changeId={view.mode === "interdiff" ? view.changeId : ""}
+						onselect={confirmChangeId}
+					/>
+				{:else}
+					<PullCommitListDiff {commits} {commitRange} oncommitCommits={confirmCommits} />
+				{/if}
+			</div>
+		{:else}
+			<div
+				class="space-y-2 rounded-sm border border-border-default bg-background-default p-4"
+			>
+				<p class="text-foreground-subtle">
+					This pull request has no versions submitted yet.
+				</p>
+				{#if isAuthor && pullState === "open" && sourceBranch}
+					<p class="text-foreground-subtle">
+						Submit from
+						<span class="typography-monospace-regular">{sourceBranch}</span>
+						to attach one.
+					</p>
+					<Button
+						icon={IterationCcw}
+						title="Submit a pull request"
+						disabled={!canResubmit || resubmit.loading}
+						loading={resubmit.loading}
+						onclick={() => resubmit.run()}
+					>
+						Submit
 					</Button>
-				{/snippet}
-			</PullCommitListHeader>
-			<ErrorAlert label={resubmit.error} />
-			{#if isInterdiff}
-				<PullCommitListInterdiff
-					{commits}
-					changeId={view.mode === "interdiff" ? view.changeId : ""}
-					onselect={confirmChangeId}
-				/>
-			{:else}
-				<PullCommitListDiff {commits} {commitRange} oncommitCommits={confirmCommits} />
-			{/if}
-		</div>
+				{/if}
+				<ErrorAlert label={resubmit.error} />
+			</div>
+		{/if}
 		<div use:stickyTrigger class="h-0"></div>
 		<!-- PR Diff -->
-		<PullDiff deps={diffDeps} diff={diff.data} error={diff.error} loading={diff.loading} />
+		{#if pull.versions.length}
+			<PullDiff deps={diffDeps} diff={diff.data} error={diff.error} loading={diff.loading} />
+		{/if}
 	</div>
 	{#if discussionOpen}
 		<div
@@ -494,7 +527,7 @@
 					pullState={pull.state}
 					conflicted={check.data?.isConflicted ?? false}
 					canChangeState={isAuthor}
-					canMerge={isAuthor}
+					canMerge={isAuthor && !!head}
 					onChangeState={setStatus.run}
 					onMerge={runMerge}
 					loading={setStatus.loading || doMerge.loading}
diff --git a/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.ts b/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.ts
index 586bee29f..75b27ab45 100644
--- a/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.ts
+++ b/web/src/routes/[handle]/[repo]/pulls/[aturi]/[version]/[[range]]/+page.ts
@@ -23,10 +23,12 @@ export const load: PageLoad = async (event) => {
 	if (route.mode === "diff") {
 		route.base =
 			commits.find((commit) => commit.hash.startsWith(route.base))?.hash ??
-			currentVersion.base;
+			currentVersion?.base ??
+			"";
 		route.head =
 			commits.find((commit) => commit.hash.startsWith(route.head))?.hash ??
-			currentVersion.head;
+			currentVersion?.head ??
+			"";
 	} else if (route.mode === "interdiff" && route.changeId) {
 		route.changeId =
 			commits.find((commit) => commit.changeId?.startsWith(route.changeId))?.changeId ?? "";
-- 
2.51.2