From e1f33e0f6b62657e3dd2a7294612460eb521e656 Mon Sep 17 00:00:00 2001
From: Sumanth V Rao <sumanthvrao@gmail.com>
Date: Wed, 5 Dec 2018 10:12:46 +0530
Subject: [PATCH] test-documentation: Add --skip-external-links option.

This option causes test-documentation to only verify internal links
that we control and are important to be correct.  This prevents
test-documentation from flaking in CI due to issues with the dozens of
third-party blocks that we link to from various parts of our
documentation.

Tweaked by tabbott for comment clarity, and to also include
github.com/zulip links.

Fixes #10942.
---
 .../spiders/common/spiders.py                 | 16 ++++++++++++++
 tools/test-documentation                      | 21 +++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/tools/documentation_crawler/documentation_crawler/spiders/common/spiders.py b/tools/documentation_crawler/documentation_crawler/spiders/common/spiders.py
index 2d0394cfac..eed40ffcc9 100644
--- a/tools/documentation_crawler/documentation_crawler/spiders/common/spiders.py
+++ b/tools/documentation_crawler/documentation_crawler/spiders/common/spiders.py
@@ -34,6 +34,7 @@ class BaseDocumentationSpider(scrapy.Spider):
     def __init__(self, *args: Any, **kwargs: Any) -> None:
         super().__init__(*args, **kwargs)
         self.has_error = False
+        self.skip_external = kwargs.get('skip_external', None)
 
     def _set_error_state(self) -> None:
         self.has_error = True
@@ -47,6 +48,18 @@ class BaseDocumentationSpider(scrapy.Spider):
     def check_existing(self, response: Any) -> None:
         self.log(response)
 
+    def _is_external_link(self, url: str) -> bool:
+        if "zulip.readthedocs" in url or "zulipchat.com" in url or "zulip.org" in url:
+            # We want CI to check any links to Zulip sites.
+            return False
+        if (len(url) > 4 and url[:4] == "file") or ("localhost" in url):
+            # We also want CI to check any links to built documentation.
+            return False
+        if 'github.com/zulip' in url:
+            # Finally, links to our own GitHub organization should always work.
+            return False
+        return True
+
     def check_permalink(self, response: Any) -> None:
         self.log(response)
         xpath_template = "//*[@id='{permalink}' or @name='{permalink}']"
@@ -74,6 +87,9 @@ class BaseDocumentationSpider(scrapy.Spider):
             elif '#' in link.url:
                 dont_filter = True
                 callback = self.check_permalink
+            if (self.skip_external is not None):   # checks if flag is set to skip external link check.
+                if (self._is_external_link(link.url)):
+                    continue
             yield Request(link.url, method=method, callback=callback, dont_filter=dont_filter,
                           errback=self.error_callback)
 
diff --git a/tools/test-documentation b/tools/test-documentation
index 900ee7b493..a8e9c3fdd2 100755
--- a/tools/test-documentation
+++ b/tools/test-documentation
@@ -12,6 +12,8 @@ case $1 in
     -h|--help)
         echo "--help, -h                   show this help message and exit"
         echo "--loglevel=LEVEL, -L LEVEL   log level (default: ERROR)"
+        echo "--skip-check-links           skip checking of links"
+        echo "--skip-external-links        skip checking of external links"
         exit 0
         ;;
     -L|--loglevel)
@@ -20,6 +22,9 @@ case $1 in
     --skip-check-links)
         skip_check_links=1
         ;;
+    --skip-external-links)
+        skip_external_links=1
+        ;;
 esac
 
 cd "$(dirname "$0")"/../docs
@@ -36,6 +41,22 @@ if [ -n "$skip_check_links" ]; then
     exit 0
 fi
 
+if [ -n "$skip_external_links" ]; then
+    color_message 94 "Testing only internal links in documentation..."
+    cd ../tools/documentation_crawler
+    set +e
+    scrapy crawl documentation_crawler -a skip_external=set "${loglevel[@]}"
+    # calling crawl directly as parameter needs to be passed
+    result=$?
+    if [ "$result" = 1 ]; then
+        color_message 91 "Failed!"
+        exit 1
+    else
+        color_message 92 "Passed!"
+        exit 0
+    fi
+fi
+
 color_message 94 "Testing links in documentation..."
 
 cd ../tools/documentation_crawler