? operator eagerly suppresses break errors

[nicowilliams]

These two should have the same output:

$ jq -n 'label $out | ((1, break $out, 2), "here", halt)'
1
$ 

$ jq -n 'label $out | ((1, break $out, 2)?, "here", halt)'
1
"here"

Whereas try gets it better, but still not entirely right:

$ jq -n 'label $out | ((try (1, break $out, 2) catch error), "here", halt)'
1
$ 

$ jq -cn 'label $out | ((try (1, break $out, 2) catch .), "here", halt)'
1
{"__jq":0}
"here"
$ 

[nicowilliams]

See also #1859.

[nicowilliams]

Actually, this is a dup of #1859.

Consider a simpler example:

$ jq -n '{a:1}|.a?|error'
jq: error (at <unknown>) (not a string): 1
$ jq -n '{a:1}|(.a)?|error'
$

In the first example the ? modifies the index operation and the compiler uses INDEX_OPT, which only suppresses generation of errors from the index operation.

In the second example the compiler fails to see the optimization opportunity and uses FORK_OPT instead, which has all the problems described in #1859.