SyntaxError: Unexpected end of JSON input when creating a merge request

[T-baby]

Description

When trying to create a merge request in a self-hosted Gitea instance, a toast notification pops up with the message: "SyntaxError: Unexpected end of JSON input". After checking the server logs, no errors were found.

Gitea Version

1.22.0

Can you reproduce the bug on the Gitea demo site?

No

Log Gist

No response

Screenshots

No response

Git Version

No response

Operating System

No response

How are you running Gitea?

Docker, version 20.10.17, running on Ubuntu 22.04.

Database

PostgreSQL

[techknowlogick]

Thanks for your report, are you able to share details of the developer console in your browser, or network tab showing what the http response shows?

[T-baby]

[matrixcloud]

same issue, any solution?

[wxiaoguang]

There were many similar reports: check your reverse-proxy (eg: nginx) & firewall & WAF, do not "deny" some requests for Gitea's backend.

If there is still a problem, please show your full configuration (including Gitea's app.ini and your reverse-proxy config), and provide a reproducible setup with detailed steps.

[T-baby]

No WAF and CDN was used, only Nginx was used for reverse proxy. The Nginx configuration is as follows:

server {
    listen       80;
    server_name  xx;
    client_max_body_size 10G;
    location / {
        proxy_pass http://gitea:3000;
        index  index.html index.htm;
    }
}

server {
    listen       443 ssl;
    server_name  xx;
    client_max_body_size 10G;
    client_header_timeout 1800s;
    client_body_timeout 1800s;
    send_timeout 1800s;
    proxy_connect_timeout 1800s;
    proxy_read_timeout 1800s;
    proxy_send_timeout 1800s;
    ssl_certificate crt;
        ssl_certificate_keykey;

    location / {
        proxy_pass http://gitea:3000;
        index  index.html index.htm;
    }
}

[wxiaoguang]

1. Please check your browser's console, to see the request URL and response header / response body. There must be some clues.
2. Please provide a reproducible setup with detailed steps. Only if it could be reproduced by others, it could have a chance to be resolved.

[wxiaoguang]

ps: Nginx could have various plugins. , so "please show your full configuration", eg: nginx -T

The config you shown is not the real one you are using, because I can see you manually prettified / changed it.

[T-baby]

This request url is: https://xx/xx/project/compare/develop...feat/dev_test

This request headers is:

This response headers is:

This response body is null.

The full configuration of nginx:

``` nginx: the configuration file /etc/nginx/nginx.conf syntax is ok nginx: configuration file /etc/nginx/nginx.conf test is successful # configuration file /etc/nginx/nginx.conf: #user nobody; worker_processes 1; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; #pid logs/nginx.pid; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; client_max_body_size 45M; #log_format main '$remote_addr - $remote_user [$time_local] "$request" ' # '$status $body_bytes_sent "$http_referer" ' # '"$http_user_agent" "$http_x_forwarded_for"'; #access_log logs/access.log main; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; #gzip on; server { listen 80; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / { root html; index index.html index.htm; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } # proxy the PHP scripts to Apache listening on 127.0.0.1:80 # #location ~ \.php$ { # proxy_pass http://127.0.0.1; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # #location ~ \.php$ { # root html; # fastcgi_pass 127.0.0.1:9000; # fastcgi_index index.php; # fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name; # include fastcgi_params; #} # deny access to .htaccess files, if Apache's document root # concurs with nginx's one # #location ~ /\.ht { # deny all; #} } # another virtual host using mix of IP-, name-, and port-based configuration # #server { # listen 8000; # listen somename:8080; # server_name somename alias another.alias; # location / { # root html; # index index.html index.htm; # } #} # HTTPS server # #server { # listen 443 ssl; # server_name localhost; # ssl_certificate cert.pem; # ssl_certificate_key cert.key; # ssl_session_cache shared:SSL:1m; # ssl_session_timeout 5m; # ssl_ciphers HIGH:!aNULL:!MD5; # ssl_prefer_server_ciphers on; # location / { # root html; # index index.html index.htm; # } #} include /etc/nginx/conf.d/*.conf; } # configuration file /etc/nginx/mime.types: types { text/html html htm shtml; text/css css; text/xml xml; image/gif gif; image/jpeg jpeg jpg; application/javascript js; application/atom+xml atom; application/rss+xml rss; text/mathml mml; text/plain txt; text/vnd.sun.j2me.app-descriptor jad; text/vnd.wap.wml wml; text/x-component htc; image/avif avif; image/png png; image/svg+xml svg svgz; image/tiff tif tiff; image/vnd.wap.wbmp wbmp; image/webp webp; image/x-icon ico; image/x-jng jng; image/x-ms-bmp bmp; font/woff woff; font/woff2 woff2; application/java-archive jar war ear; application/json json; application/mac-binhex40 hqx; application/msword doc; application/pdf pdf; application/postscript ps eps ai; application/rtf rtf; application/vnd.apple.mpegurl m3u8; application/vnd.google-earth.kml+xml kml; application/vnd.google-earth.kmz kmz; application/vnd.ms-excel xls; application/vnd.ms-fontobject eot; application/vnd.ms-powerpoint ppt; application/vnd.oasis.opendocument.graphics odg; application/vnd.oasis.opendocument.presentation odp; application/vnd.oasis.opendocument.spreadsheet ods; application/vnd.oasis.opendocument.text odt; application/vnd.openxmlformats-officedocument.presentationml.presentation pptx; application/vnd.openxmlformats-officedocument.spreadsheetml.sheet xlsx; application/vnd.openxmlformats-officedocument.wordprocessingml.document docx; application/vnd.wap.wmlc wmlc; application/wasm wasm; application/x-7z-compressed 7z; application/x-cocoa cco; application/x-java-archive-diff jardiff; application/x-java-jnlp-file jnlp; application/x-makeself run; application/x-perl pl pm; application/x-pilot prc pdb; application/x-rar-compressed rar; application/x-redhat-package-manager rpm; application/x-sea sea; application/x-shockwave-flash swf; application/x-stuffit sit; application/x-tcl tcl tk; application/x-x509-ca-cert der pem crt; application/x-xpinstall xpi; application/xhtml+xml xhtml; application/xspf+xml xspf; application/zip zip; application/octet-stream bin exe dll; application/octet-stream deb; application/octet-stream dmg; application/octet-stream iso img; application/octet-stream msi msp msm; audio/midi mid midi kar; audio/mpeg mp3; audio/ogg ogg; audio/x-m4a m4a; audio/x-realaudio ra; video/3gpp 3gpp 3gp; video/mp2t ts; video/mp4 mp4; video/mpeg mpeg mpg; video/quicktime mov; video/webm webm; video/x-flv flv; video/x-m4v m4v; video/x-mng mng; video/x-ms-asf asx asf; video/x-ms-wmv wmv; video/x-msvideo avi; } # configuration file /etc/nginx/conf.d/gitea.conf: server { listen 80; server_name xx; client_max_body_size 10G; location / { proxy_pass http://gitea:3000; index index.html index.htm; } } server { listen 443 ssl; server_name xx; client_max_body_size 10G; client_header_timeout 1800s; client_body_timeout 1800s; send_timeout 1800s; proxy_connect_timeout 1800s; proxy_read_timeout 1800s; proxy_send_timeout 1800s; ssl_certificate crt; ssl_certificate_key key; location / { proxy_pass http://gitea:3000; index index.html index.htm; } } ```

[wxiaoguang]

I think it is still related to your network or config.

1. There are a lot of unrelated cookies in your request header, it seems that there might be some middle device (or app) between you and your server.
2. I didn't not see the response code, but it is still likely the problem occurs before Gitea server (not related to Gitea), so I guess you also have never seen the "merge" request reaches Gitea server.
3. So still the same suggestion as above:
   • Check you network & environment
   • Reproduce it on a clear server then others could help to debug
   • Otherwise I don't think we could make new progress here

[wxiaoguang]

Maybe your request is rejected by Tencent Cloud.

[T-baby]

I tried using it in the browser's incognito mode, but I still couldn't merge. The complete headers of requests and response are as follows:

POST /xx/xx/compare/develop...feat/dev_test HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate, br, zstd
Accept-Language: zh-CN,zh;q=0.9
Cache-Control: no-cache
Connection: keep-alive
Content-Length: 890
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryS8dz1rWTyhWCS8rN
Cookie: i_like_gitea=f033aa68145ed416; lang=zh-CN; _csrf=Hb7iUYpQYTXXr0aq9pt4RtfBA-Y6MTcyMTg3NzQxNTIyMjg2NTk5MA
DNT: 1
Host: xx
Origin: https://xx
Pragma: no-cache
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36
sec-ch-ua: "Not/A)Brand";v="8", "Chromium";v="126", "Google Chrome";v="126"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "macOS"
x-csrf-token: Hb7iUYpQYTXXr0aq9pt4RtfBA-Y6MTcyMTg3NzQxNTIyMjg2NTk5MA

HTTP/1.1 200 OK
Server: nginx/1.23.0
Date: Thu, 25 Jul 2024 03:17:45 GMT
Content-Length: 0
Connection: keep-alive
Cache-Control: max-age=0, private, must-revalidate, no-transform
X-Frame-Options: SAMEORIGIN

We are unable to create a merge request only for this repository. It works fine for all others.

[wxiaoguang]

Try go use other servers than Tencent Cloud.

[T-baby]

Try go use other servers than Tencent Cloud.

We are not using Tencent Cloud servers.

[wxiaoguang]

Try go use other servers than Tencent Cloud.尝试使用除腾讯云之外的其他服务器。

We are not using Tencent Cloud servers.

Then: "please provide a reproducible setup with detailed steps."

[wxiaoguang]

You could provide the reproducible setup by a docker-compose file and some related commands, to make others could also reproduce the problem on their side.

[wolfogre]

I received another report similar to this issue. And this time it can indeed be found in Gitea's logs that it received the request and returned a response with zero status code.

2024/08/15 03:32:59 ...eb/routing/logger.go:102:func1() [I] router: completed POST /[hidden]/compare/[hidden]...[hidden] for [hidden], 0 in 1563.2ms @ repo/pull.go:1223(repo.CompareAndPullRequestPost)

IIRC, the framework will return 200 with an empty body if WriteHeader hasn't been called.

No idea how it could happen, but maybe there is something going wrong with Gitea.

[wxiaoguang]

More context and a new clue:

https://github.com/go-gitea/gitea/issues/31893#issuecomment-2300630715

That PR alone didn't fix it but looking at the response in the network section of the browser we were now with the nightly getting a proper error 500 back that indicated somehow there was a .lock file on that repo left over that was blocking this. i removed it and it worked!