Command make add-snippet can fail in some cases

[krysgor]

Adding a new binary catalog using the make add-snippet command fails in some cases.

The reason for this problem is here: capture-snippet.sh:119. In cases where the input variable SELECTED_RESULT contains leading blanks, the OFFSET calculation will lead to an empty result.

Steps to reproduce the issue:

cd syft/pkg/cataloger/binary/test-fixtures
make
make add-snippet

Then select: classifiers/bin/curl/8.9.1/linux-amd64/curl and choose one of the found maches:

1) 167585 curl/8.9.1
2) 174376 curl 8.9.1 (x86_64-pc-linux-musl) %s

Then the process fails with:

Pattern not found.
Error: command execution failed: exit status 1
Usage:
  manager add-snippet [flags]

Flags:
  -h, --help                help for add-snippet
      --length int          the length of the snippet to capture (default 100)
      --prefix-length int   number of bytes before the search hit to capture (default 20)
      --search-for string   the pattern to search for in the binary (defaults to the version)

command execution failed: exit status 1
exit status 1
make: *** [Makefile:23: add-snippet] Error 1

What you expected to happen:
The process contiues wihout error, like this:

1) 167585 curl/8.9.1
2) 174376 curl 8.9.1 (x86_64-pc-linux-musl) %s

Please select a match: 2

0002a914: 616c 206f 7220 222d 2d68 656c 7020 616c  al or "--help al
0002a924: 6c22 2e00 6375 726c 2038 2e39 2e31 2028  l"..curl 8.9.1 (
0002a934: 7838 365f 3634 2d70 632d 6c69 6e75 782d  x86_64-pc-linux-
0002a944: 6d75 736c 2920 2573 0a00 0000 5741 524e  musl) %s....WARN
0002a954: 494e 473a 2063 7572 6c20 616e 6420 6c69  ING: curl and li
0002a964: 6263 7572 6c20 7665 7273 696f 6e73 2064  bcurl versions d
0002a974: 6f20 6e6f 7420 6d61 7463 682e 2046 756e  o not match. Fun
0002a984: 6374 696f 6e61 6c69                      ctionali

Does this snippet capture what you need? (Y/n/q) y
wrote snippet to "classifiers/snippets/curl/8.9.1/linux-amd64/curl"

Environment:

• syft main branch latest

[krysgor]

Thanks for fast merge!