From c578e5f243c6955dbdc4ba8a3318a39403e5b5e2 Mon Sep 17 00:00:00 2001
From: Andrew Klychkov <aklychko@redhat.com>
Date: Wed, 27 Aug 2025 21:13:36 +0200
Subject: [PATCH] postgresql_db: fix conn_limit 0 bug (#880)

(cherry picked from commit 64aaa3dd20b9d8e38916e15c06fec6810ab75499)
---
 .../fragments/879-fix-conn-limit-zero.yml     |   2 +
 plugins/modules/postgresql_db.py              |   4 +-
 .../targets/postgresql_db/tasks/main.yml      |   3 +
 .../tasks/postgresql_db_conn_limit_zero.yml   | 104 ++++++++++++++++++
 4 files changed, 111 insertions(+), 2 deletions(-)
 create mode 100644 changelogs/fragments/879-fix-conn-limit-zero.yml
 create mode 100644 tests/integration/targets/postgresql_db/tasks/postgresql_db_conn_limit_zero.yml

diff --git a/changelogs/fragments/879-fix-conn-limit-zero.yml b/changelogs/fragments/879-fix-conn-limit-zero.yml
new file mode 100644
index 00000000..59332031
--- /dev/null
+++ b/changelogs/fragments/879-fix-conn-limit-zero.yml
@@ -0,0 +1,2 @@
+bugfixes:
+  - postgresql_db - Fix connection limit not being set when value is "0" (https://github.com/ansible-collections/community.postgresql/issues/879). 
diff --git a/plugins/modules/postgresql_db.py b/plugins/modules/postgresql_db.py
index 671e561d..6b3eaa7b 100644
--- a/plugins/modules/postgresql_db.py
+++ b/plugins/modules/postgresql_db.py
@@ -479,7 +479,7 @@ def db_update(cursor, db, owner, encoding, lc_collate, lc_ctype, icu_locale, loc
     if owner and owner != db_info['owner']:
         changed = set_owner(cursor, db, owner)
 
-    if conn_limit and conn_limit != str(db_info['conn_limit']):
+    if conn_limit != '' and conn_limit != str(db_info['conn_limit']):
         changed = set_conn_limit(cursor, db, conn_limit)
 
     if tablespace and tablespace != db_info['tablespace']:
@@ -513,7 +513,7 @@ def db_matches(cursor, db, owner, template, encoding, lc_collate, lc_ctype, icu_
             return False
         elif owner and owner != db_info['owner']:
             return False
-        elif conn_limit and conn_limit != str(db_info['conn_limit']):
+        elif conn_limit != '' and conn_limit != str(db_info['conn_limit']):
             return False
         elif tablespace and tablespace != db_info['tablespace']:
             return False
diff --git a/tests/integration/targets/postgresql_db/tasks/main.yml b/tests/integration/targets/postgresql_db/tasks/main.yml
index 2c5fc7c9..6db4c577 100644
--- a/tests/integration/targets/postgresql_db/tasks/main.yml
+++ b/tests/integration/targets/postgresql_db/tasks/main.yml
@@ -48,3 +48,6 @@
 
 # Test the comment feature
 - import_tasks: postgresql_db_comment.yml
+
+# Test connection limit zero fix (issue #879)
+- import_tasks: postgresql_db_conn_limit_zero.yml
diff --git a/tests/integration/targets/postgresql_db/tasks/postgresql_db_conn_limit_zero.yml b/tests/integration/targets/postgresql_db/tasks/postgresql_db_conn_limit_zero.yml
new file mode 100644
index 00000000..23b42c1e
--- /dev/null
+++ b/tests/integration/targets/postgresql_db/tasks/postgresql_db_conn_limit_zero.yml
@@ -0,0 +1,104 @@
+---
+# Test for connection limit zero fix (issue #879)
+- name: Test connection limit zero - Create DB with conn_limit 0
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_db:
+    name: test_conn_limit_zero
+    state: present
+    conn_limit: "0"
+    login_user: "{{ pg_user }}"
+  register: result
+
+- assert:
+    that:
+      - result is changed
+      - result.executed_commands == ['CREATE DATABASE "test_conn_limit_zero" CONNECTION LIMIT 0']
+
+- name: Test connection limit zero - Verify conn_limit is actually set to 0
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_query:
+    query: "SELECT datconnlimit AS conn_limit FROM pg_database WHERE datname = 'test_conn_limit_zero'"
+  register: result
+
+- assert:
+    that:
+      - result.rowcount == 1
+      - result.query_result[0]['conn_limit'] == 0
+
+- name: Test connection limit zero - Run the same task again (should not change)
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_db:
+    name: test_conn_limit_zero
+    state: present
+    conn_limit: "0"
+    login_user: "{{ pg_user }}"
+  register: result
+
+- assert:
+    that:
+      - result is not changed
+
+- name: Test connection limit zero - Change conn_limit to 100
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_db:
+    name: test_conn_limit_zero
+    state: present
+    conn_limit: "100"
+    login_user: "{{ pg_user }}"
+  register: result
+
+- assert:
+    that:
+      - result is changed
+      - result.executed_commands == ['ALTER DATABASE "test_conn_limit_zero" CONNECTION LIMIT 100']
+
+- name: Test connection limit zero - Verify conn_limit is changed to 100
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_query:
+    query: "SELECT datconnlimit AS conn_limit FROM pg_database WHERE datname = 'test_conn_limit_zero'"
+  register: result
+
+- assert:
+    that:
+      - result.rowcount == 1
+      - result.query_result[0]['conn_limit'] == 100
+
+- name: Test connection limit zero - Change conn_limit back to 0
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_db:
+    name: test_conn_limit_zero
+    state: present
+    conn_limit: "0"
+    login_user: "{{ pg_user }}"
+  register: result
+
+- assert:
+    that:
+      - result is changed
+      - result.executed_commands == ['ALTER DATABASE "test_conn_limit_zero" CONNECTION LIMIT 0']
+
+- name: Test connection limit zero - Verify conn_limit is back to 0
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_query:
+    query: "SELECT datconnlimit AS conn_limit FROM pg_database WHERE datname = 'test_conn_limit_zero'"
+  register: result
+
+- assert:
+    that:
+      - result.rowcount == 1
+      - result.query_result[0]['conn_limit'] == 0
+
+- name: Test connection limit zero - Cleanup test DB
+  become_user: "{{ pg_user }}"
+  become: true
+  postgresql_db:
+    name: test_conn_limit_zero
+    state: absent
+    login_user: "{{ pg_user }}"