"You're about to run a destructive command" for command that isn't destructive.

[fake-name]

webarchive> ALTER TABLE web_pages ADD CONSTRAINT test_unique_url UNIQUE (url);
You're about to run a destructive command.
Do you want to proceed? (y/n):

Adding a constraint isn't destructive. Why am I getting a warning? Is pgcli doing something else when I add a constraint?

Your environment

• [x] Please provide your OS and version information.

  durr@postgres-server ~> uname -a
  Linux postgres-server 4.15.0-45-generic #48-Ubuntu SMP Tue Jan 29 16:28:13 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
  durr@postgres-server ~> cat /etc/lsb-release
  DISTRIB_ID=Ubuntu
  DISTRIB_RELEASE=18.04
  DISTRIB_CODENAME=bionic
  DISTRIB_DESCRIPTION="Ubuntu 18.04.2 LTS"

• [x] Please provide your CLI version.

  durr@postgres-server ~> sudo -H -u postgres pgcli
  """
  Server: PostgreSQL 11.2
  Version: 2.0.2

• [x] What is the output of pip freeze command.

durr@postgres-server ~> pip freeze
asn1crypto==0.24.0
attrs==17.4.0
Automat==0.6.0
bottle==0.12.13
certifi==2018.1.18
chardet==3.0.4
cli-helpers==1.1.0
click==6.7
colorama==0.3.7
configobj==5.0.6
constantly==15.1.0
cryptography==2.1.4
cycler==0.10.0
docker==2.5.1
docker-pycreds==0.2.1
Glances==2.11.1
humanize==0.5.1
hyperlink==17.3.1
idna==2.6
incremental==16.10.1
influxdb==4.1.1
iotop==0.6
matplotlib==2.1.1
netifaces==0.10.4
numpy==1.13.3
olefile==0.45.1
PAM==0.4.2
pgcli==2.0.2
pgspecial==1.11.5
Pillow==5.1.0
ply==3.11
prompt-toolkit==2.0.9
psutil==5.4.2
psycopg2==2.7.7
pyasn1==0.4.2
pyasn1-modules==0.2.1
pycryptodomex==3.4.7
pycurl==7.43.0.1
Pygments==2.3.1
pygobject==3.26.1
pyOpenSSL==17.5.0
pyparsing==2.2.0
pyserial==3.4
pysmi==0.2.2
pysnmp==4.4.3
pystache==0.5.4
python-apt==1.6.3+ubuntu1
python-dateutil==2.6.1
pytz==2018.3
PyYAML==3.12
requests==2.18.4
service-identity==16.0.0
setproctitle==1.1.10
six==1.11.0
sqlparse==0.2.4
tabulate==0.8.3
terminaltables==3.1.0
Twisted==17.9.0
unattended-upgrades==0.1
urllib3==1.22
wcwidth==0.1.7
websocket-client==0.44.0
zope.interface==4.3.2

I assume this is some sort of "double check on ALTER commands" thing, but well, it's sufficently dumb about it that it only serves to be annoying. Why was this even implemented?

If you're going to add warning popups with wording that make it sound like you're going to delete stuff, make sure it only happens when you're actually going to delete stuff!

If you can't fully disambiguate if a command is actually destructive, don't call them destructive commands.

I still think this entire feature is dumb, but maybe say "You're about to run a ALTER/Whatever command. This may irrevocably delete data. Continue?", or some similar verbiage that at least is aware that not all ALTER commands delete stuff.

[amjith]

Hi. You're right it is implemented naively. We simply check if it is an ALTER command display the warning.

I'm open to changing the verbiage, feel free to open a PR. If you want to turn off that warning you can also do that via your config file. Check for the words destructive_warning.