Issue 2: Reference Coupling

[birdflyi]

This is an issue.
#1 //项目内引用-相对
#2 //自引用-相对
@w4qed32 //空引-相对
https://github.com/birdflyi/test //项目url
https://github.com/birdflyi/test/issues/new //项目内issue
#1 //项目内引用
#2 //自引用
#1 //项目内引用-完整url
#2 //自引用-完整url
birdflyi/test@w4qed32 //空引
X-lab2017/open-research#2 或者 X-lab2017/open-research@06f8ad9 //他引
^(.)/(.)#[0-9]? //正则：event
^(.)/(.*)@[0-9a-z]{7} //正则：commit

[birdflyi]

对照源码：

This is an issue.
#1  //项目内引用-相对
#2  //自引用-相对
@w4qed32  //空引-相对
https://github.com/birdflyi/test  //项目url
https://github.com/birdflyi/test/issues/new  //项目内issue
birdflyi/test#1  //项目内引用
birdflyi/test#2  //自引用
https://github.com/birdflyi/test/issues/1  //项目内引用-完整url
https://github.com/birdflyi/test/issues/2  //自引用-完整url
birdflyi/test@w4qed32  //空引
 X-lab2017/OpenResearch#2 或者 X-lab2017/OpenResearch@06f8ad9  //他引
^(.*)/(.*)#[0-9]*?  //正则：event
^(.*)/(.*)@[0-9a-z]{7}  //正则：commit

[birdflyi]

对比：
#1
birdflyi/test#1
sensu/sensu#449
sensu/sensu#449
sensu/sensu#449 //混乱的引用
源码：

https://github.com/birdflyi/test/issues/1
[birdflyi/test#1](https://github.com/birdflyi/test/issues/1)
https://github.com/sensu/sensu/issues/449
[sensu/sensu#449](https://github.com/sensu/sensu/issues/449)
[sensu/sensu#449](https://github.com/birdflyi/test/issues/1)  //混乱的引用

示例：
sensu/sensu#449 (comment) （此处源码https://github.com/sensu/sensu/issues/449#issuecomment-12612084）

结论

推荐使用完整url引用（即https://github.com/OWNER/PROJECT/issues/1），避免[OWNER/PROJECT#1](https://github.com/ABC/XYZ/issues/1)混乱引用的问题，避免相对引用#1在级联提交PR后指向更改的问题。

完整url引用：url指向项目内会自动显示为#1的相对引用，url指向项目外会自动显示为OWNER/PROJECT#1；格式详见[1]中Table 1 。

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[1] Blincoe, K., Harrison, F., Kaur, N., & Damian, D. (2019). Reference coupling: An exploration of inter-project technical dependencies and their characteristics within large software ecosystems. Information and Software Technology, 110, 174-189.

[birdflyi]

分析comment body的时候，#2或者@06f8ad9 (共7位sha码)都是可能的形式，较容易和@人名混。按引用格式正则匹配的字符串需要清洗。