find alternative download feature

[ArTourter]

The find alternative download option is only offered after a checksum mismatch. If the source file isn't found (error 404) the option is not offered.

This is currently the case with makemkv where upstream removes old packages:

===
Processing makemkv

makemkv:
makemkv not found in /var/cache/sbopkg.
--2018-05-22 10:00:21-- http://www.makemkv.com/download/makemkv-oss-1.12.0.tar.gz
Resolving www.makemkv.com (www.makemkv.com)... 104.18.62.176, 104.18.63.176, 2400:cb00:2048:1::6812:3eb0, ...
Connecting to www.makemkv.com (www.makemkv.com)|104.18.62.176|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2018-05-22 10:00:21 ERROR 404: Not Found.

makemkv:
Would you like to continue processing the rest of the
queue or would you like to abort? If this failed
package is a dependency of another package in the queue
then it may not make sense to continue.

(Y)es to continue, (N)o to abort, (R)etry the build?:

===
whereas if I modify the slackbuild with 1.12.2 but not change the checksum, I get:

Processing makemkv

makemkv:
makemkv not found in /var/cache/sbopkg.
--2018-05-22 10:02:12-- http://www.makemkv.com/download/makemkv-oss-1.12.2.tar.gz
Resolving www.makemkv.com (www.makemkv.com)... 104.18.62.176, 104.18.63.176, 2400:cb00:2048:1::6812:3fb0, ...
Connecting to www.makemkv.com (www.makemkv.com)|104.18.62.176|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4379033 (4.2M) [application/x-gzip]
Saving to: ‘makemkv-oss-1.12.2.tar.gz’

makemkv-oss-1.12.2. 100%[===================>] 4.18M 12.1MB/s in 0.3s

2018-05-22 10:02:12 (12.1 MB/s) - ‘makemkv-oss-1.12.2.tar.gz’ saved [4379033/4379033]

Found makemkv-oss-1.12.2.tar.gz in /var/cache/sbopkg.
Checking MD5SUM:
MD5SUM check for makemkv-oss-1.12.2.tar.gz ... FAILED!
Expected: ffa31b99b6654db142bcc42a77cef489
Found: 2f9b765106aea740ddd51a69939d98a6

Do you want to use the downloaded makemkv source:
makemkv-oss-1.12.2.tar.gz in /var/cache/sbopkg?

You can choose among the following options:

• (Y)es, keep the source and continue the build process;
• (N)o, delete the source and abort the build process;
• (R)etry download and continue the build process; or
• (A)ttempt to download from third party source repository.
  (Y)es, (N)o, (R)etry, (A)lternative ?:

[willysr]

@swmarc can you take a look on this one?

[swmarc]

@willysr Well, I did not study the sbopkg source yet, but just made changes to sqg in the past.
Maybe someone that is more familiar with code base could step in for now?

[willysr]

Oh yeah, it was orbea.
Sorry for that.

@orbea, can you look at this issue?

Thanks

[orbea]

@willysr I'm not sure why you are asking me? I'm fairly certain my one commit to sbopkg which I forgot to apply locally would not cause this.

But I did take a look at this, it appears when there is no downloaded source sbopkg's only choices are Y, N and R.

https://github.com/sbopkg/sbopkg/blob/master/src/usr/sbin/sbopkg#L2939

Removing this line exposes the option, but the A option did not successfully download an alternative source tarball?

[orbea]

I suppose its not supposed to download anything? The make_archive_url function doesn't seem to do anything besides echo an url.

https://github.com/sbopkg/sbopkg/blob/master/src/usr/sbin/sbopkg#L3022

Edit: Nvm, I see why it doesn't download, it grabs an index.html.

ORIG DOWNLOAD = http://www.makemkv.com/download/makemkv-oss-1.12.0.tar.gz
DOWNLOAD = http://slackware.uk/sbosrcarch/by-md5/f/f/ffa31b99b6654db142bcc42a77cef489/.

[willysr]

@orbea no, it wasn't caused by your commit (yours are great), but i think that since you had the original idea, you have the answer why the alternatives are only working when there's a mismatch in the checksum and not in the missing source in the first time, hence the op was asking.
Sorry if it confused you.....