Fix(Core): prevent twice 'date_mod' updates

[stonebuzz]

Checklist before requesting a review

Please delete options that are not relevant.

• I have read the CONTRIBUTING document.
• I have performed a self-review of my code.
• I have added tests that prove my fix is effective or that my feature works.
• This change requires a documentation update.

Description

Bug found with fields plugin (but all plugins could be impacted when)

The fields plugin (after managing additional fields) adds a date_mod in the mainitem's input to update only last modification date.

when the update occurs glpi checks if date_mod exists in $this->fields, and if so, adds it to $this->updates (which already contains date_mode -> because of fields plugin)

if (array_key_exists('date_mod', $this->fields)) {
    // is a non blacklist field exists
    if (count(array_diff($this->updates, $this->history_blacklist)) > 0) {
        $this->fields['date_mod'] = $_SESSION["glpi_currenttime"];
        $this->updates[$x++]      = 'date_mod';
    }
}

When glpihandle locked fields, this

$idx = array_search('date_mod', $fields);
if ($idx !== false) {
    unset($fields[$idx]);
}

doesn't work perfectly because the date_mod value exists twice and array_search returns only the first occurrence found.

So we need to check if date_mod alrady exist in $this->updates

To sum up, it is currently impossible to update only date_mod without causing a lock on this field (for dynamic item).

Set is_dynamic to false is not a good solution either, as it removes the link between the mainitem and related agent.

• It fixes date_mod (core) field locked when asset is updated  pluginsGLPI/fields#849

Screenshots (if appropriate):

[stonebuzz]

I close i favor of -> https://github.com/glpi-project/glpi/pull/18120/files (I hadn't seen)

[ladenree76000]

it looks fine, date_mod is no longer locked 👍

[stonebuzz]

@ladenree76000

preferred #18120