image_filter.t case failed: tengine feature image_filter_crop_offset

[chobits]

Ⅰ. Issue Description

With macro #(T_NGX_HTTP_IMAGE_FILTER) in image_filter module, the compiled nginx binary failed to run image_filter.t

Ⅳ. How to reproduce it (as minimally and precisely as possible)

When we disable source included in this macro, this case will pass.

TEST_NGINX_LEAVE=yes \
TEST_NGINX_UNSAFE=yes \
TEST_NGINX_BINARY=$nginx_binary \
prove -v -I $nginx_tests_lib_path $proxy_connect_test_cases

ok 36 - rotate after resize                                                 
not ok 37 - resize rotate nested                                                                                                                        
#   Failed test 'resize rotate nested'                                      
#   at tests/nginx-tests/nginx-tests/image_filter.t line 254.               
#          got: '12 10'                                                     
#     expected: '10 12' 

ENV prepared for this case

sudo cpanm --notest GD 

sudo apt install -y libgd-dev

[chobits]

this pr https://github.com/alibaba/tengine/pull/380 broke default value of conf->angle, then made the case failed.

[chobits]

• log format: log_format time "$request_uri:$status:$upstream_response_time"; like(http_get('/time.log'), qr!/t3:.*, [1-9].!, 'upstream response time');

• Normal output of t3 time log is something like this:

/bad:404:-
/t1:204:0.001
/t2:204:0.004
/big:200:-
/slow:200:-                     < ----- from case: http_get('/slow');
/slow:444:-                     <----- from case http_get('/t3');
/slow:444:-                       |
/slow:444:-                       |        same request (multiple upstream tries)
/slow:200:-                       '---------------------
/empty:204:-
/t3:204:0.000, 0.000, 0.001, 0.000, 2.406 : 0.001

• Wrong output of incorrect case like this:

 /bad:404:-
 /t1:204:0.000
 /t2:204:0.000
 /big:200:-
 /slow:200:-               < ----- from case: http_get('/slow');
 /slow:200:-              <----- from case http_get('/t3');   // not upstream retry
 /empty:204:-
 /t3:204:2.408 : 0.000

-> It seems that tengine randomize upstream peers. ( ఠൠఠ )ﾉ

[chobits]

I think I find out the point, this issue is caused by tengine feature random initialization of upstream peers.

This logic is enabled by default, see this C macro in source:

 auto/modules:have=T_NGX_HTTP_UPSTREAM_RANDOM . auto/have