nicer errors

appview/pages/templates/repo/pulls/new.html

···
         <ul class="list-decimal pl-10 space-y-2 text-gray-700 dark:text-gray-300">
             <li class="leading-relaxed">Clone this repository.</li>
             <li class="leading-relaxed">Make your changes in your local repository.</li>
-            <li class="leading-relaxed">Grab the diff using <code class="bg-gray-100 dark:bg-gray-700 px-1 py-0.5 rounded text-gray-800 dark:text-gray-200 font-mono text-sm">git diff</code>.</li>
+            <li class="leading-relaxed">Grab the diff using <code>git diff</code>.</li>
             <li class="leading-relaxed">Paste the diff output in the form below.</li>
         </ul>
     </p>
···
             <label for="targetBranch" class="dark:text-white">configure branches</label>
             <div class="flex flex-wrap gap-2 items-center">
               <select
+                  required
                   name="targetBranch"
                   class="p-1 border border-gray-200 bg-white dark:bg-gray-700 dark:text-white dark:border-gray-600"
                   >
···
           </div>
 
           <div class="mt-4">
-              <label for="patch" class="dark:text-white">paste your patch here</label>
-              <textarea
-                  name="patch"
-                  id="patch"
-                  rows="10"
-                  class="w-full resize-y font-mono dark:bg-gray-700 dark:text-white dark:border-gray-600"
-                  placeholder="Paste your git diff output here."
-              ></textarea>
+            {{ $label := "paste your patch here" }}
+            {{ $rows := 10 }}
+            {{ if .RepoInfo.Roles.IsPushAllowed }}
+              {{ $label = "or paste your patch here" }}
+              {{ $rows = 4 }}
+            {{ end }}
+
+            <label for="patch" class="dark:text-white">{{ $label }}</label>
+            <textarea
+                name="patch"
+                id="patch"
+                rows="{{$rows}}"
+                class="w-full resize-y font-mono dark:bg-gray-700 dark:text-white dark:border-gray-600"
+                placeholder="Paste your git diff output here."
+            ></textarea>
           </div>
 
-          <div class="flex items-center gap-2">
-              <button type="submit" class="btn">create</button>
-              <button class="btn">TODO preview</button>
+          <div class="flex justify-end items-center gap-2">
+            <button type="submit" class="btn">create</button>
           </div>
 
         </div>
         <div id="pull" class="error dark:text-red-300"></div>
     </form>
 {{ end }}
+
+{{ define "repoAfter" }}
+<div id="patch-preview" class="error dark:text-red-300"></div>
+{{ end }}

appview/pages/templates/repo/pulls/pull.html

···
                 <span class="select-none before:content-['\00B7']"></span>
                 <time>{{ .Pull.Created | timeFmt }}</time>
                 <span class="select-none before:content-['\00B7']"></span>
-                <span>targeting
+                <span>
+                  patch targeting
                   <span class="text-xs rounded bg-gray-100 dark:bg-gray-700 text-black dark:text-white font-mono px-2 mx-1/2 inline-flex items-center">
                     {{ .Pull.TargetBranch }}
                   </span>

appview/pages/templates/repo/pulls/pulls.html

···
                     </span>
 
                     <span class="before:content-['·']">
-                        targeting
+                        patch targeting
                         <span class="text-xs rounded bg-gray-100 dark:bg-gray-600 text-black dark:text-white font-mono px-2 mx-1/2 inline-flex items-center">
                           {{ .TargetBranch }}
                         </span>

appview/state/pull.go

···
 			Branches:     result.Branches,
 		})
 	case http.MethodPost:
+		isPushAllowed := f.RepoInfo(s, user).Roles.IsPushAllowed()
 		title := r.FormValue("title")
 		body := r.FormValue("body")
 		targetBranch := r.FormValue("targetBranch")
 		sourceBranch := r.FormValue("sourceBranch")
 		patch := r.FormValue("patch")
 
-		if sourceBranch == "" && patch == "" {
-			s.pages.Notice(w, "pull", "neither sourceBranch nor patch supplied")
+		if patch == "" {
+			if isPushAllowed && sourceBranch == "" {
+				s.pages.Notice(w, "pull", "Neither source branch nor patch supplied.")
+				return
+			}
+			s.pages.Notice(w, "pull", "Patch is empty.")
+			return
+		}
+
+		if patch != "" && sourceBranch != "" {
+			s.pages.Notice(w, "pull", "Cannot select both patch and source branch.")
 			return
 		}
 
 		if title == "" || body == "" || targetBranch == "" {
-			s.pages.Notice(w, "pull", "Title, body and patch diff are required.")
+			s.pages.Notice(w, "pull", "Title, body and target branch are required.")
 			return
 		}
-
-		isPushAllowed := f.RepoInfo(s, user).Roles.IsPushAllowed()
 
 		// TODO: check if knot has this capability
 		var pullSource *db.PullSource
···
 		s.pages.HxLocation(w, fmt.Sprintf("/%s/pulls/%d", f.OwnerSlashRepo(), pullId))
 		return
 	}
-}
-
-func (s *State) RenderDiffFragment(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *State) ResubmitPull(w http.ResponseWriter, r *http.Request) {