simonhamp · Nov 7, 2026 · Nov 6, 2026
diff --git a/app/Devnull/Data/BodyRun.php b/app/Devnull/Data/BodyRun.php
@@ -5,13 +5,14 @@
 /**
  * A run of a paragraph: plain prose, a mention, inline code, a link, or a
  * standalone `/dev/null`, which draws as the wordmark, or a hex color, which
- * draws with a swatch of it. A link's text is the URL as written, and a
- * color's is the color as written, `#` included. A mention of a GitHub
- * organization has its handle in $username too, and $isOrganization set.
+ * draws with a swatch of it, or a hashtag, which searches commits for it. A
+ * link's text is the URL as written, and a color's or a hashtag's is as
+ * written, `#` included. A mention of a GitHub organization has its handle in
+ * $username too, and $isOrganization set.
  */
 final readonly class BodyRun
 {
-    public function __construct(public string $text, public ?string $username = null, public bool $isCode = false, public bool $isWordmark = false, public ?BodyLink $link = null, public ?string $color = null, public bool $isOrganization = false) {}
+    public function __construct(public string $text, public ?string $username = null, public bool $isCode = false, public bool $isWordmark = false, public ?BodyLink $link = null, public ?string $color = null, public bool $isOrganization = false, public bool $isHashtag = false) {}
 
     public function isMention(): bool
     {

diff --git a/app/Devnull/Data/CommitBody.php b/app/Devnull/Data/CommitBody.php
@@ -4,12 +4,12 @@
 
 /**
  * Turns a commit's `body_segments` into blocks to draw, the way the web's
- * CommitBody does: prose (with URLs and mentions linked, hex colors beside a
- * swatch, and `/dev/null` as the wordmark) and inline code flow together in
- * paragraphs, lines that start with `>` group into quotes, and fenced code
- * blocks stand on their own.
+ * CommitBody does: prose (with URLs, mentions and hashtags linked, hex colors
+ * beside a swatch, and `/dev/null` as the wordmark) and inline code flow
+ * together in paragraphs, lines that start with `>` group into quotes, and
+ * fenced code blocks stand on their own.
  *
- * Mention and color offsets count code points into the whole body, but segments aren't
+ * Mention, color and hashtag offsets count code points into the whole body, but segments aren't
  * exact slices of it: inline code loses its backticks, a block its fences, and
  * prose the line break next to a block. So each segment is found in the body,
  * moving forward, and mentions are placed by where their segment starts.
@@ -41,6 +41,14 @@ final class CommitBody
      */
     private const string Color = '/(?:(?<!\S)|(?<=\n>))[#\x{FF03}]([0-9a-f]{8}|[0-9a-f]{6}|(?=[0-9]*[a-f]|0)[0-9a-f]{3,4})(?=\p{P}*(?:[\s\x{00AD}\x{2060}\x{200A}-\x{200D}\x{20E2}]|\z))/iu';
 
+    /**
+     * A hashtag: a `#` and a letter, then letters, marks, digits and
+     * underscores, not straight after a word character, `&`, `/`, `#`, `>` or
+     * `-`, so `a#b`, `&#123;` and a URL's fragment aren't one. The web's rule,
+     * from linkified-text.tsx.
+     */
+    private const string Hashtag = '/(?<![\p{L}\p{M}\p{N}_&\/#>-])#\p{L}[\p{L}\p{M}\p{N}_]*/u';
+
     /**
      * A `/dev/null` that stands on its own, not part of a longer path, a word
      * or a name. The web's rule, from withWordmarks() in linkified-text.tsx.
@@ -116,6 +124,7 @@ public static function blocks(string $body, ?array $segments, array $mentions =
         $runs = [];
         $cursor = 0;
         $colors = self::colors($body);
+        $hashtags = self::hashtags($body);
 
         foreach ($segments as $segment) {
             switch ($segment['type'] ?? null) {
@@ -132,12 +141,12 @@ public static function blocks(string $body, ?array $segments, array $mentions =
                     $start = $text === '' ? false : mb_strpos($body, $text, $cursor);
 
                     if ($start === false) {
-                        array_push($runs, ...self::withLinks($text.($cut ? self::Ellipsis : ''), null, [], []));
+                        array_push($runs, ...self::withLinks($text.($cut ? self::Ellipsis : ''), null, [], [], []));
 
                         break;
                     }
 
-                    array_push($runs, ...self::withLinks($text, $start, $mentions, $colors));
+                    array_push($runs, ...self::withLinks($text, $start, $mentions, $colors, $hashtags));
                     $cursor = $start + mb_strlen($text);
 
                     if ($cut) {
@@ -193,7 +202,7 @@ private static function paragraphs(array $runs): array
         $quoted = false;
 
         foreach ($runs as $run) {
-            $prose = ! $run->isMention() && ! $run->isCode && ! $run->isWordmark && $run->link === null && ! $run->isColor();
+            $prose = ! $run->isMention() && ! $run->isCode && ! $run->isWordmark && $run->link === null && ! $run->isColor() && ! $run->isHashtag;
 
             $lines = $prose
                 ? array_map(fn (string $text): BodyRun => new BodyRun($text), preg_split('/(?<=\n)/', $run->text, flags: PREG_SPLIT_NO_EMPTY) ?: [])
@@ -266,15 +275,16 @@ private static function withoutTrailingBreak(array $runs): array
      *
      * @param  list<Mention>  $mentions
      * @param  list<array{0: int, 1: int, 2: string}>  $colors
+     * @param  list<array{0: int, 1: int}>  $hashtags
      * @return list<BodyRun>
      */
-    private static function withLinks(string $text, ?int $start, array $mentions, array $colors): array
+    private static function withLinks(string $text, ?int $start, array $mentions, array $colors, array $hashtags): array
     {
         $runs = [];
         $position = 0;
         $prose = fn (string $part, int $at): array => $start === null
             ? self::withWordmarks($part)
-            : self::withMentions($part, $start + $at, $mentions, $colors);
+            : self::withMentions($part, $start + $at, $mentions, $colors, $hashtags);
 
         foreach (BodyLink::in($text) as [$offset, $length, $link]) {
             if ($offset > $position) {
@@ -297,9 +307,10 @@ private static function withLinks(string $text, ?int $start, array $mentions, ar
      *
      * @param  list<Mention>  $mentions
      * @param  list<array{0: int, 1: int, 2: string}>  $colors
+     * @param  list<array{0: int, 1: int}>  $hashtags
      * @return list<BodyRun>
      */
-    private static function withMentions(string $text, int $start, array $mentions, array $colors): array
+    private static function withMentions(string $text, int $start, array $mentions, array $colors, array $hashtags): array
     {
         $runs = [];
         $position = 0;
@@ -321,15 +332,15 @@ private static function withMentions(string $text, int $start, array $mentions,
             }
 
             if ($offset > $position) {
-                array_push($runs, ...self::withColors(mb_substr($text, $position, $offset - $position), $start + $position, $colors));
+                array_push($runs, ...self::withColors(mb_substr($text, $position, $offset - $position), $start + $position, $colors, $hashtags));
             }
 
             $runs[] = new BodyRun($handle, username: $mention->username, isOrganization: $mention->isOrganization);
             $position = $offset + $mention->length;
         }
 
         if ($position < $length) {
-            array_push($runs, ...self::withColors(mb_substr($text, $position), $start + $position, $colors));
+            array_push($runs, ...self::withColors(mb_substr($text, $position), $start + $position, $colors, $hashtags));
         }
 
         return $runs;
@@ -340,9 +351,10 @@ private static function withMentions(string $text, int $start, array $mentions,
      * in the whole body that fall inside it, as the web's withColors() does.
      *
      * @param  list<array{0: int, 1: int, 2: string}>  $colors
+     * @param  list<array{0: int, 1: int}>  $hashtags
      * @return list<BodyRun>
      */
-    private static function withColors(string $text, int $start, array $colors): array
+    private static function withColors(string $text, int $start, array $colors, array $hashtags): array
     {
         $runs = [];
         $position = 0;
@@ -355,11 +367,42 @@ private static function withColors(string $text, int $start, array $colors): arr
                 continue;
             }
 
-            array_push($runs, ...self::withWordmarks(mb_substr($text, $position, $offset - $position)));
+            array_push($runs, ...self::withHashtags(mb_substr($text, $position, $offset - $position), $start + $position, $hashtags));
             $runs[] = new BodyRun(mb_substr($text, $offset, $colorLength), color: $value);
             $position = $offset + $colorLength;
         }
 
+        array_push($runs, ...self::withHashtags(mb_substr($text, $position), $start + $position, $hashtags));
+
+        return $runs;
+    }
+
+    /**
+     * Splits prose that starts at $start in the body around the hashtags
+     * found in the whole body that fall inside it, as the web's withHashtags()
+     * does. One a color already took, like `#fff`, never falls inside.
+     *
+     * @param  list<array{0: int, 1: int}>  $hashtags
+     * @return list<BodyRun>
+     */
+    private static function withHashtags(string $text, int $start, array $hashtags): array
+    {
+        $runs = [];
+        $position = 0;
+        $length = mb_strlen($text);
+
+        foreach ($hashtags as [$offset, $hashtagLength]) {
+            $offset -= $start;
+
+            if ($offset < $position || $offset + $hashtagLength > $length) {
+                continue;
+            }
+
+            array_push($runs, ...self::withWordmarks(mb_substr($text, $position, $offset - $position)));
+            $runs[] = new BodyRun(mb_substr($text, $offset, $hashtagLength), isHashtag: true);
+            $position = $offset + $hashtagLength;
+        }
+
         array_push($runs, ...self::withWordmarks(mb_substr($text, $position)));
 
         return $runs;
@@ -375,11 +418,7 @@ private static function withColors(string $text, int $start, array $colors): arr
      */
     private static function colors(string $body): array
     {
-        $prose = '';
-
-        foreach (self::parts($body) as $index => $part) {
-            $prose .= $index % 2 === 0 ? $part : str_repeat(' ', mb_strlen($part));
-        }
+        $prose = self::prose($body);
 
         preg_match_all(self::Color, "\n".$prose, $matches, PREG_SET_ORDER | PREG_OFFSET_CAPTURE);
 
@@ -390,6 +429,40 @@ private static function colors(string $body): array
         ], $matches);
     }
 
+    /**
+     * The hashtags in the body's prose, in order, as where each starts and how
+     * long it is in code points, `#` included. Code is blanked out first, so
+     * nothing in it counts.
+     *
+     * @return list<array{0: int, 1: int}>
+     */
+    private static function hashtags(string $body): array
+    {
+        $prose = self::prose($body);
+
+        preg_match_all(self::Hashtag, $prose, $matches, PREG_OFFSET_CAPTURE);
+
+        return array_map(fn (array $match): array => [
+            mb_strlen(substr($prose, 0, $match[1])),
+            mb_strlen($match[0]),
+        ], $matches[0]);
+    }
+
+    /**
+     * The body with its code blanked out to spaces of the same length, so
+     * what is found in the prose keeps its place in the body.
+     */
+    private static function prose(string $body): string
+    {
+        $prose = '';
+
+        foreach (self::parts($body) as $index => $part) {
+            $prose .= $index % 2 === 0 ? $part : str_repeat(' ', mb_strlen($part));
+        }
+
+        return $prose;
+    }
+
     /**
      * Splits prose around each standalone `/dev/null`, which becomes a
      * wordmark run. Like the web, the prose between two mentions is looked at

diff --git a/app/NativeComponents/Concerns/OpensHashtags.php b/app/NativeComponents/Concerns/OpensHashtags.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace App\NativeComponents\Concerns;
+
+/**
+ * A tapped hashtag searches commits for it, as the web's links to its search
+ * page with the hashtag, `#` included, as the term. Search opens in the tab it
+ * was tapped in (see OpensInTab, which the screen uses too) with the hashtag
+ * in its field and the commits for it loading.
+ */
+trait OpensHashtags
+{
+    public function openHashtag(string $hashtag): void
+    {
+        $this->openInTab('/search', ['query' => $hashtag]);
+    }
+}
diff --git a/app/NativeComponents/Concerns/ShowsCommits.php b/app/NativeComponents/Concerns/ShowsCommits.php
@@ -43,6 +43,7 @@
 trait ShowsCommits
 {
     use OpensCommitSheet;
+    use OpensHashtags;
     use OpensStargazers;
     use VotesOnPolls;
     use WritesInBackground;

diff --git a/app/NativeComponents/Conversation.php b/app/NativeComponents/Conversation.php
@@ -24,6 +24,7 @@
 use App\Icons\Lucide;
 use App\Models\PendingWrite;
 use App\NativeComponents\Concerns\AttachesPhotos;
+use App\NativeComponents\Concerns\OpensHashtags;
 use App\NativeComponents\Concerns\OpensInTab;
 use App\NativeComponents\Concerns\PlaysVoiceNotes;
 use App\NativeComponents\Concerns\RecordsVoiceNotes;
@@ -103,6 +104,7 @@
 class Conversation extends NativeComponent
 {
     use AttachesPhotos;
+    use OpensHashtags;
     use OpensInTab;
     use PlaysVoiceNotes;
     use RecordsVoiceNotes;

diff --git a/app/NativeComponents/ScheduledCommits.php b/app/NativeComponents/ScheduledCommits.php
@@ -9,6 +9,7 @@
 use App\Devnull\SiteLink;
 use App\Devnull\Timezone;
 use App\Devnull\Toasts;
+use App\NativeComponents\Concerns\OpensHashtags;
 use App\NativeComponents\Concerns\OpensInTab;
 use App\NativeComponents\Concerns\RefreshesInBackground;
 use App\NativeComponents\Concerns\TalksToDevnull;
@@ -36,6 +37,7 @@
  */
 class ScheduledCommits extends NativeComponent
 {
+    use OpensHashtags;
     use OpensInTab;
     use RefreshesInBackground;
     use TalksToDevnull;

diff --git a/app/NativeComponents/Search.php b/app/NativeComponents/Search.php
@@ -31,6 +31,10 @@
  * devnull won't search commits for fewer than three characters, so a shorter
  * term only finds developers.
  *
+ * A hashtag tapped in a commit or a message opens it with the hashtag as the
+ * term ($data['query']), searched straight away, as the web's hashtag links
+ * do, and the field isn't focused, so the keyboard leaves the results in view.
+ *
  * Neither answer is kept (see ResponseCache): a search is about the moment.
  */
 class Search extends NativeComponent
@@ -66,6 +70,11 @@ class Search extends NativeComponent
 
     public string $query = '';
 
+    /**
+     * Whether the field takes focus when the screen opens: only for an empty one, as on the web.
+     */
+    public bool $autofocus = true;
+
     /** @var list<Connection> */
     public array $people = [];
 
@@ -87,6 +96,16 @@ class Search extends NativeComponent
      */
     private ?RowCache $rowCache = null;
 
+    public function mount(): void
+    {
+        $query = $this->data('query');
+
+        if (is_string($query) && trim($query) !== '') {
+            $this->autofocus = false;
+            $this->pick($query);
+        }
+    }
+
     public function navTitle(): string
     {
         return 'Search';
@@ -106,6 +125,14 @@ public function pick(string $term): void
         $this->search();
     }
 
+    /**
+     * A hashtag in one of the results searches for it here, in place of what's in the field.
+     */
+    public function openHashtag(string $hashtag): void
+    {
+        $this->pick($hashtag);
+    }
+
     public function open(string $username): void
     {
         $person = $this->person($username);

diff --git a/resources/views/native/partials/commit-body.blade.php b/resources/views/native/partials/commit-body.blade.php
@@ -13,6 +13,9 @@
     A hex color has a square of that color before it, as the web's swatch, held to it by a narrow no-break space so
     they wrap together.
 
+    A hashtag is medium weight in Commit Blue and searches commits for it on a tap, as the web's. In the composer's
+    preview ($static), as in the web's static preview, it stays plain text.
+
     A quote, lines that start with ">", sits behind an amber rule on the left like the web's blockquote, its
     runs drawn as a paragraph's.
 
@@ -52,6 +55,8 @@
 <native:text :text="$run->link->shown" class="text-theme-primary" @press="openLink('{{ $commit->id }}', {{ $linkIndex++ }})" />
 @elseif ($run->isColor())
 <native:text><native:text text="■" class="text-[#{{ $run->color }}] dark:text-[#{{ $run->color }}]" />&#x202F;<native:text :text="$run->text" /></native:text>
+@elseif ($run->isHashtag && ! ($static ?? false))
+<native:text :text="$run->text" font="medium" class="font-medium text-theme-primary" @press="openHashtag('{{ $run->text }}')" />
 @elseif ($run->isWordmark)
 @php($afterSpace = $loop->index > 0 && ctype_space(substr($block->runs[$loop->index - 1]->text, -1)))
 <native:text font="semibold" class="font-semibold tracking-tight">@if ($afterSpace)&#x200B;@endif/&#x2060;dev<native:text text="/" class="text-outline text-theme-lane-0" />&#x2060;null</native:text>

diff --git a/resources/views/native/partials/composer-preview.blade.php b/resources/views/native/partials/composer-preview.blade.php
@@ -8,7 +8,7 @@
     @if (trim($sheetBody) === '' && $sheetImages === [] && $sheetPoll === null)
         <native:text class="w-full text-[15px] leading-relaxed text-theme-ink-muted">Nothing to preview yet.</native:text>
     @else
-        @include('native.partials.commit-body', ['commit' => $draftCommit, 'focused' => true])
+        @include('native.partials.commit-body', ['commit' => $draftCommit, 'focused' => true, 'static' => true])
         @include('native.partials.commit-media', ['commit' => $draftCommit, 'withEmbeds' => false, 'scoreAction' => false])
         @if ($draftCommit->poll)
             <native:column ref="sheet-draft-poll" class="w-full mt-3 gap-2" a11y-label="Poll options">