Thanks so much for this report.
I have been struggling for days to diagnose a problem with my local test site running under WAMP which does not occur (thankfully) on my live website. I have a button in one of my modules which downloads a dynamically constructed XLSX file, and this suddenly started to hang the server. In addition, the Preview buttons on my DHTML Text Area fields started to report "Server Not Responding ... Please Try later".
After completely reconstructing all my self-signed certificates (the live server has a real certificate), and updating my local Apache logging, I realized that almost all requests to the local test site were returning a 404 status, but the pages themselves were still rendering normally. I got some minimal success by changing the code to force a 200 status when returning the preview text and my XLSX file. But still the Software Engineer in me needed to understand why this functionality suddenly stopped working.
My local test server is a development platform and as such it has several Xoops modules installed which are not on the live server.
I had installed xSitemap (1.56 Final) intending to use it to build a list of all my pages as I transition the site to Xoops 2.5.11 and Bootswatch 5.3. This report encouraged me to look more closely at what was installed on the local test site. When I discovered that both xmnews and xSitemap had the new index.php files mentioned in this post, I uninstalled them as a test. And suddenly things were back to normal.
After some additional tracing and testing, I offer the annotated segment from my Apache access log which clearly demonstrates that there is something about xSitemap when installed in Xoops 2.5.10 that causes the erroneous 404 status in the Http Response.
================================ start with clean Xoops 2510 ==================================
local-test-site [04/Apr/2022:17:25:45 -0400] "GET / HTTP/1.1" 200 15168
================================ install xsitemap, go to home page ==============================
local-test-site [04/Apr/2022:17:26:30 -0400] "GET /admin.php HTTP/1.1" 200 37858
local-test-site [04/Apr/2022:17:26:35 -0400] "GET /modules/system/admin.php?fct=modulesadmin HTTP/1.1" 200 48318
local-test-site [04/Apr/2022:17:26:38 -0400] "GET /modules/system/admin.php?fct=modulesadmin&op=installlist HTTP/1.1" 200 33177
local-test-site [04/Apr/2022:17:26:44 -0400] "GET /modules/system/admin.php?fct=modulesadmin&op=install&module=xsitemap HTTP/1.1" 200 23461
local-test-site [04/Apr/2022:17:26:48 -0400] "POST /modules/system/admin.php HTTP/1.1" 200 33186
local-test-site [04/Apr/2022:17:26:52 -0400] "GET / HTTP/1.1" 200 15324
================================ close browser/reopen website, refresh page =====================
local-test-site [04/Apr/2022:17:28:12 -0400] "GET / HTTP/1.1" 302 310
local-test-site [04/Apr/2022:17:28:12 -0400] "GET / HTTP/1.1" 404 15439
local-test-site [04/Apr/2022:17:29:33 -0400] "GET /themes/xswatch4/js/bootstrap.bundle.min.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:29:33 -0400] "GET /themes/xswatch4/js/cookieconsent.min.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:29:33 -0400] "GET /themes/xswatch4/js/js.cookie.min.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:29:33 -0400] "GET /include/xoops.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:29:33 -0400] "GET / HTTP/1.1" 404 15439
local-test-site [04/Apr/2022:17:29:33 -0400] "GET /browse.php?Frameworks/jquery/jquery.js HTTP/1.1" 200 86927
local-test-site [04/Apr/2022:17:29:34 -0400] "GET /themes/xswatch4/images/logo.png HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:29:34 -0400] "GET /themes/xswatch4/images/favicon.png HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:29:34 -0400] "GET /themes/xswatch4/images/toolsicon.png HTTP/1.1" 304 -
================================ close browser/reopen website ===================================
local-test-site [04/Apr/2022:17:39:28 -0400] "GET / HTTP/1.1" 302 310
local-test-site [04/Apr/2022:17:39:28 -0400] "GET / HTTP/1.1" 404 15439
================================ uninstall xsitemap, go to home page ============================
local-test-site [04/Apr/2022:17:40:34 -0400] "GET /admin.php HTTP/1.1" 404 39613
local-test-site [04/Apr/2022:17:40:38 -0400] "GET /modules/system/admin.php?fct=modulesadmin HTTP/1.1" 404 54733
local-test-site [04/Apr/2022:17:40:44 -0400] "GET /modules/system/admin.php?fct=modulesadmin&op=uninstall&module=xsitemap HTTP/1.1" 404 24801
local-test-site [04/Apr/2022:17:40:47 -0400] "POST /modules/system/admin.php HTTP/1.1" 404 2858
local-test-site [04/Apr/2022:17:40:50 -0400] "GET / HTTP/1.1" 200 15053
================================= close browser/reopen website, refresh page ====================
local-test-site [04/Apr/2022:17:42:38 -0400] "GET / HTTP/1.1" 302 310
local-test-site [04/Apr/2022:17:42:38 -0400] "GET / HTTP/1.1" 200 15168
local-test-site [04/Apr/2022:17:42:41 -0400] "GET /themes/xswatch4/js/cookieconsent.min.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:42:41 -0400] "GET /themes/xswatch4/js/bootstrap.bundle.min.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:42:41 -0400] "GET /include/xoops.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:42:41 -0400] "GET /themes/xswatch4/js/js.cookie.min.js HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:42:41 -0400] "GET / HTTP/1.1" 200 15168
local-test-site [04/Apr/2022:17:42:41 -0400] "GET /browse.php?Frameworks/jquery/jquery.js HTTP/1.1" 200 86927
local-test-site [04/Apr/2022:17:42:42 -0400] "GET /themes/xswatch4/images/logo.png HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:42:42 -0400] "GET /themes/xswatch4/images/toolsicon.png HTTP/1.1" 304 -
local-test-site [04/Apr/2022:17:42:42 -0400] "GET /themes/xswatch4/images/favicon.png HTTP/1.1" 304 -
==================================================================================================
The scenario is as follows:
1. Start with a clean install of Xoops 2510
2. Install xSitemap and press the button to go to the website Home Page
At this point accessing the website still returns a 200 status.
3. Close the browser and reopen the website
At this point almost all requests return the 404 status.
Installing xSitemap in Xoops 2.5.11 does not have the same result.
The xmnews module does not seem to have the same effect, so I do not think the index.php files could be causing the problem. I have done exhaustive debugging through the site startup with xSitemap installed and I can't see anything that might shed any light on the cause. But something in xSitemap is not playing well with Xoops 2510.