From cfc5f4a095064bbeea14825b890fd3c9b18904e8 Mon Sep 17 00:00:00 2001
From: Alexis Sellier <self@cloudhead.io>
Date: Wed, 2 Mar 2022 11:41:49 +0100
Subject: [PATCH] Improve project error handling

Fail gracefully if we can't load a peer.

Signed-off-by: Alexis Sellier <self@cloudhead.io>
---
 src/Placeholder.svelte                | 29 +++++++++++++
 src/base/projects/Browser.svelte      | 40 ++++++------------
 src/base/projects/Project.svelte      | 61 +++++++++++++++++----------
 src/base/projects/ProjectRoute.svelte |  2 +-
 src/project.ts                        |  6 ++-
 5 files changed, 86 insertions(+), 52 deletions(-)
 create mode 100644 src/Placeholder.svelte

diff --git a/src/Placeholder.svelte b/src/Placeholder.svelte
new file mode 100644
index 000000000..4d48bb2f4
--- /dev/null
+++ b/src/Placeholder.svelte
@@ -0,0 +1,29 @@
+<script lang="ts">
+  export let icon: string;
+</script>
+
+<style>
+  .placeholder {
+    text-align: center;
+    border-radius: 0.25rem;
+    padding-bottom: 2rem;
+    color: var(--color-foreground-faded) !important;
+    background-color: var(--color-foreground-background);
+  }
+  .placeholder header {
+    padding: 1rem 0;
+    font-weight: bold;
+  }
+  .placeholder .icon {
+    font-size: 1.5rem;
+    margin-bottom: 1rem;
+  }
+</style>
+
+<div class="error error-message placeholder">
+  <header>
+    <div class="icon">{icon}</div>
+    <slot name="title"></slot>
+  </header>
+  <slot name="body"></slot>
+</div>
diff --git a/src/base/projects/Browser.svelte b/src/base/projects/Browser.svelte
index c69673519..d6afc1908 100644
--- a/src/base/projects/Browser.svelte
+++ b/src/base/projects/Browser.svelte
@@ -2,6 +2,7 @@
   import type { Readable } from 'svelte/store';
   import * as proj from '@app/project';
   import Loading from '@app/Loading.svelte';
+  import Placeholder from '@app/Placeholder.svelte';
   import * as utils from '@app/utils';
 
   import Tree from './Tree.svelte';
@@ -100,27 +101,9 @@
     width: 100%;
   }
 
-  .error-grey {
-    color: var(--color-foreground-faded) !important;
-    background-color: var(--color-foreground-background);
-  }
-
   .source-tree {
     overflow-x: hidden;
   }
-  .file-not-found {
-    text-align: center;
-    border-radius: 0.25rem;
-    padding-bottom: 2rem;
-  }
-  .file-not-found header {
-    padding: 1rem 0;
-    font-weight: bold;
-  }
-  .file-not-found .icon {
-    font-size: 1.5rem;
-    margin-bottom: 1rem;
-  }
   nav {
     padding: 0 2rem;
   }
@@ -181,19 +164,20 @@
             <Blob line={browser.line} {blob} />
           {/if}
         {:catch}
-          <div class="error error-grey error-message file-not-found">
-            <header>
-              <div class="icon">🍂</div>
+          <Placeholder icon="🍂">
+            <span slot="title">
               {#if path != "/"}
                 <div><code>{path}</code></div>
               {/if}
-            </header>
-            {#if path == "/"}
-              The README could not be loaded.
-            {:else}
-              This path could not be loaded.
-            {/if}
-          </div>
+            </span>
+            <span slot="body">
+              {#if path == "/"}
+                The README could not be loaded.
+              {:else}
+                This path could not be loaded.
+              {/if}
+            </span>
+          </Placeholder>
         {/await}
       </div>
     {/if}
diff --git a/src/base/projects/Project.svelte b/src/base/projects/Project.svelte
index 04156ca4a..9e6adea3b 100644
--- a/src/base/projects/Project.svelte
+++ b/src/base/projects/Project.svelte
@@ -3,6 +3,7 @@
   import type { Config } from '@app/config';
   import * as proj from '@app/project';
   import Avatar from '@app/Avatar.svelte';
+  import Placeholder from '@app/Placeholder.svelte';
   import Clipboard from '@app/Clipboard.svelte';
   import { formatProfile, formatSeedId, setOpenGraphMetaTag } from '@app/utils';
   import { browserStore } from '@app/project';
@@ -17,7 +18,7 @@
   export let config: Config;
   export let project: proj.Project;
   export let content: proj.ProjectContent;
-  export let revision: string;
+  export let revision: string | null;
 
   let parentName = project.profile ? formatProfile(project.profile.nameOrAddress, config) : null;
   let pageTitle = parentName ? `${parentName}/${project.name}` : project.name;
@@ -49,9 +50,6 @@
 </script>
 
 <style>
-  header {
-    padding: 0 2rem 0 8rem;
-  }
   .title {
     display: flex;
     align-items: center;
@@ -87,8 +85,12 @@
     margin: 1rem 0 1.5rem 0;
   }
 
+  .content {
+    padding: 0 2rem 0 8rem;
+  }
+
   @media (max-width: 960px) {
-    header {
+    .content {
       padding-left: 2rem;
     }
 
@@ -112,7 +114,7 @@
   <title>{pageTitle}</title>
 </svelte:head>
 
-<header>
+<header class="content">
   <div class="title bold">
     {#if project.profile}
       <a class="org-avatar" title={project.profile.nameOrAddress} href="/{project.profile.nameOrAddress}">
@@ -134,22 +136,37 @@
   <div class="description">{project.description}</div>
 </header>
 
-{#await project.getRoot(revision) then { tree, commit }}
-  <Header {tree} {commit} {browserStore} {project} peerSelector={! project.profile} />
+{#if revision}
+  {#await project.getRoot(revision) then { tree, commit }}
+    <Header {tree} {commit} {browserStore} {project} peerSelector={! project.profile} />
 
-  {#if content == proj.ProjectContent.Tree}
-    <Browser {project} {tree} {browserStore} />
-  {:else if content == proj.ProjectContent.History}
-    <History {project} {commit} />
-  {:else if content == proj.ProjectContent.Commit}
-    <Commit {project} {commit} />
-  {/if}
-{:catch err}
-  <div class="container center-content">
-    <div class="error error-message text-xsmall">
-      <!-- TODO: Differentiate between (1) commit doesn't exist and (2) failed
-           to fetch - this needs a change to the backend. -->
-      API request to <code class="text-xsmall">{err.url}</code> failed
+    {#if content == proj.ProjectContent.Tree}
+      <Browser {project} {tree} {browserStore} />
+    {:else if content == proj.ProjectContent.History}
+      <History {project} {commit} />
+    {:else if content == proj.ProjectContent.Commit}
+      <Commit {project} {commit} />
+    {/if}
+  {:catch err}
+    <div class="container center-content">
+      <div class="error error-message text-xsmall">
+        <!-- TODO: Differentiate between (1) commit doesn't exist and (2) failed
+             to fetch - this needs a change to the backend. -->
+        API request to <code class="text-xsmall">{err.url}</code> failed
+      </div>
     </div>
+  {/await}
+{:else}
+  <div class="content">
+    {#if peer}
+      <Placeholder icon="🍂">
+        <span slot="title"><code>{formatSeedId(peer)}</code></span>
+        <span slot="body">Couldn't load remote source tree.</span>
+      </Placeholder>
+    {:else}
+      <Placeholder icon="🍂">
+        <span slot="body">Couldn't load source tree.</span>
+      </Placeholder>
+    {/if}
   </div>
-{/await}
+{/if}
diff --git a/src/base/projects/ProjectRoute.svelte b/src/base/projects/ProjectRoute.svelte
index c5ee4b2ba..65a13875b 100644
--- a/src/base/projects/ProjectRoute.svelte
+++ b/src/base/projects/ProjectRoute.svelte
@@ -16,7 +16,7 @@
   export let hash: string | null = null;
 
   const browse: proj.BrowseTo = { content, peer, path: "/" };
-  const head = project.branches[project.defaultBranch];
+  const head = project.branches[project.defaultBranch] || null;
 
   // If line-number hash changes, we update the browser.
   $: browse.line = formatLocationHash(hash);
diff --git a/src/project.ts b/src/project.ts
index 56d1a001b..6689c3bc7 100644
--- a/src/project.ts
+++ b/src/project.ts
@@ -349,7 +349,11 @@ export class Project implements ProjectInfo {
     };
 
     if (peer) {
-      remote = await Project.getRemote(urn, peer, seed.api);
+      try {
+        remote = await Project.getRemote(urn, peer, seed.api);
+      } catch {
+        remote.heads = {};
+      }
     }
 
     return new Project(urn, info, seed, peers, remote.heads, profile, anchors);