From ab58d24c038e4de51dfb9913b88dbca1fc67d53d Mon Sep 17 00:00:00 2001
From: Egor Kislitsyn <egor@kislitsyn.com>
Date: Thu, 21 Feb 2019 14:30:59 +0700
Subject: [PATCH] do not match hashtags consisting entirely of numbers

---
 lib/auto_linker/parser.ex |  7 +++++--
 test/auto_linker_test.exs | 12 ++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/lib/auto_linker/parser.ex b/lib/auto_linker/parser.ex
index c675bb1..74d50ee 100644
--- a/lib/auto_linker/parser.ex
+++ b/lib/auto_linker/parser.ex
@@ -362,8 +362,11 @@ defmodule AutoLinker.Parser do
 
   def match_hashtag(buffer) do
     case Regex.run(@match_hashtag, buffer, capture: [:tag]) do
-      [hashtag] -> hashtag
-      _ -> nil
+      [hashtag] ->
+        if Regex.match?(~r/#\d+$/, hashtag), do: nil, else: hashtag
+
+      _ ->
+        nil
     end
   end
 
diff --git a/test/auto_linker_test.exs b/test/auto_linker_test.exs
index ad26d81..49a592b 100644
--- a/test/auto_linker_test.exs
+++ b/test/auto_linker_test.exs
@@ -152,6 +152,18 @@ defmodule AutoLinkerTest do
              ) == expected
     end
 
+    test "must have non-numbers" do
+      expected = "<a href=\"/t/1ok\">#1ok</a> #42 #7"
+
+      assert AutoLinker.link("#1ok #42 #7",
+               hashtag: true,
+               hashtag_prefix: "/t/",
+               class: false,
+               rel: false,
+               new_window: false
+             ) == expected
+    end
+
     test "do not turn urls with hashes into hashtags" do
       text = "google.com#test #test google.com/#test #tag"