Taken from `Perl::Critic`:
A common idiom in perl for dealing with possible errors is to use `eval`
followed by a check of `$@`/`$EVAL_ERROR`:
eval {
...
};
if ($EVAL_ERROR) {
...
}
There's a problem with this: the value of `$EVAL_ERROR` (`$@`) can change
between the end of the `eval` and the `if` statement. The issue are object
destructors:
package Foo;
...
sub DESTROY {
...
eval { ... };
...
}
package main;
eval {
my $foo = Foo->new();
...
};
if ($EVAL_ERROR) {
...
}
Assuming there are no other references to `$foo` created, when the
`eval` block in `main` is exited, `Foo::DESTROY()` will be invoked,
regardless of whether the `eval` finished normally or not. If the `eval`
in `main` fails, but the `eval` in `Foo::DESTROY()` succeeds, then
`$EVAL_ERROR` will be empty by the time that the `if` is executed.
Additional issues arise if you depend upon the exact contents of
`$EVAL_ERROR` and both `eval`s fail, because the messages from both will
be concatenated.
Even if there isn't an `eval` directly in the `DESTROY()` method code,
it may invoke code that does use `eval` or otherwise affects
`$EVAL_ERROR`.
The solution is to ensure that, upon normal exit, an `eval` returns a
true value and to test that value:
# Constructors are no problem.
my $object = eval { Class->new() };
# To cover the possiblity that an operation may correctly return a
# false value, end the block with "1":
if ( eval { something(); 1 } ) {
...
}
eval {
...
1;
}
or do {
# Error handling here
};
Unfortunately, you can't use the `defined` function to test the result;
`eval` returns an empty string on failure.
Various modules have been written to take some of the pain out of
properly localizing and checking `$@`/`$EVAL_ERROR`. For example:
use Try::Tiny;
try {
...
} catch {
# Error handling here;
# The exception is in $_/$ARG, not $@/$EVAL_ERROR.
}; # Note semicolon.
"But we don't use DESTROY() anywhere in our code!" you say. That may be
the case, but do any of the third-party modules you use have them? What
about any you may use in the future or updated versions of the ones you
already use?
I came across https://github.com/NixOS/hydra/issues/751 and realized
that hydra-notify is responsible for creating the additional jobsets in
a declarative file. My declarative testing works in dev now.
The original code would return standard "Please come back later" page when there
are only fetch errors on a newly setup declarative project. The problem is that
there are two types of errors: standard errors and fetch errors. Each is
acompanied by a corresponding field for time of occurence. Standard errors use
'errortime', while fetch errors have 'lastchecktime' set to the time of the
error. Unfortunately, jobset.tt file was only using 'errortime' for displaying
the time. This would result in the following errors in logs:
Couldn't render template "date error - bad time/date string: expects 'hⓂ️s dⓂ️y' got: ''
This change includes using 'lastchecktime' when rendering the error times.
The current implementation will pass all values to `create_or_update` method. The
missing values will end up as `undef` (or `NULL`) when assigned to `%update`.
Thus, for columns that are NOT NULL, when, for example, flakes are not used,
will result in a horrible:
DBIx::Class::Storage::DBI::_dbh_execute(): DBI Exception: DBD::Pg::st execute failed:
ERROR: null value in column "type" violates not-null constraint
DETAIL: Failing row contains (.jobsets, 118, hydra, hydra jobsets, src, hydra/jobsets.nix, null,
null, null, 1589536378, 1, 0, 0, , 3, 30, 100, null, null, 1589536379, null, null). [for Statement
"UPDATE jobsets SET checkinterval = ?, description = ?, enableemail = ?, nixexprinput = ?,
nixexprpath = ?, type = ? WHERE ( ( name = ? AND project = ? ) )" with ParamValues: 1='30',
2='hydra jobsets', 3='0', 4='src', 5='hydra/jobsets.nix', 6=undef, 7='.jobsets', 8='hydra'] at
/nix/store/lsf81ip9ybxihk5praf2n0nh14a6i9j0-hydra-0.1.19700101.DIRTY/libexec/hydra/lib/Hydra/Helper/AddBuilds.pm line 50
This change just omits adding such values to `%update`, which results in
PostgreSQL assigning the default values.
This adds a `devShell` which unlike `runHydra` doesn't start hydra
automatically and doesn't receive hydra as build input. It is better
suited for interactive development cycles:
```
$ nix-shell -A devShell
$ ./bootstrap
$ configurePhase
$ make
$ # hack hack hack
$ foreman start
# test test test
<C-c>
$ # hack hack hack
```
runHyda automatically starts hydra and postgres:
```
$ nix-shell -A runHydra
```
The shell receives hydra from the working copy as buildInput.
Running hydra, queue-runner, evaluator and postgres is managed
by foreman (https://github.com/ddollar/foreman) and configured
in `Procfile`.
The previous code converted option values to ints when the value
contained a digit somewhere. This is too eager since it also converts
strings like `release-0.2` to an int which should not happen.
We now only convert to int when the value is an integer.
