Fix alias_dsn detection for --list-dsn and -D

AUTHORS

@@ -152,6 +152,7 @@ Contributors:
     * Shayan Golshani (shgol)
     * Tommi Kyntölä (kynde)
     * Diego
+    * Chris (ChrisJr404)
 
 Creator:
 --------

changelog.rst

@@ -3,6 +3,13 @@ Upcoming (TBD)
 
 Bug fixes:
 ----------
+* Fix ``--list-dsn`` and ``-D``/``--dsn`` not finding ``[alias_dsn]`` entries.
+  Both read the config with a bare ``load_config`` that skips the packaged
+  default, so on a fresh install (no config written yet) ``--list-dsn`` printed
+  a misleading "Invalid DSNs found" error and ``-D`` could crash on the missing
+  ``[main]`` section. They now load config the same way as the rest of pgcli
+  (``get_config``), which writes the default template if needed and always has
+  the expected sections ([issue 1489](https://github.com/dbcli/pgcli/issues/1489)).
 * Restore cursor shape behaviour for Emacs mode
 * Fix ``TypeError: cannot use a string pattern on a bytes-like object`` when
   completion metadata comes back as bytes (e.g. ``SQL_ASCII`` client encoding).

pgcli/main.py

@@ -1575,7 +1575,7 @@ def cli(
             )
     if list_dsn:
         try:
-            cfg = load_config(pgclirc, config_full_path)
+            cfg = get_config(pgclirc)
             for alias in cfg["alias_dsn"]:
                 click.secho(alias + " : " + cfg["alias_dsn"][alias])
             sys.exit(0)
@@ -1627,7 +1627,7 @@ def cli(
     if list_databases or ping_database:
         database = "postgres"
 
-    cfg = load_config(pgclirc, config_full_path)
+    cfg = get_config(pgclirc)
     if dsn != "":
         try:
             dsn_config = cfg["alias_dsn"][dsn]

tests/test_alias_dsn.py

@@ -0,0 +1,90 @@
+import pytest
+from click.testing import CliRunner
+
+from pgcli.main import cli, PGCli
+
+
+def write_config(tmp_path, body):
+    cfg = tmp_path / "config"
+    cfg.write_text(body)
+    return cfg
+
+
+@pytest.fixture
+def isolate_config(monkeypatch, tmp_path):
+    # Keep the real config dir out of the picture. get_config() writes its
+    # default template under here when a config file does not exist yet.
+    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path))
+    return tmp_path
+
+
+def test_list_dsn_fresh_config(isolate_config):
+    # No config file exists yet. --list-dsn used to read the not-yet-written
+    # config before PGCli() created it, hit a KeyError on the missing
+    # [alias_dsn] section, and print "Invalid DSNs found" with exit code 1.
+    # It should just report no aliases and exit cleanly.
+    cfg = isolate_config / "config"
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--pgclirc", str(cfg), "--list-dsn"])
+    assert result.exit_code == 0
+    assert "Invalid DSNs" not in result.output
+    assert result.output.strip() == ""
+
+
+def test_list_dsn_lists_aliases(isolate_config):
+    cfg = write_config(
+        isolate_config,
+        "[alias_dsn]\n"
+        "foo = postgres://u:p@localhost:5432/foo\n"
+        "bar = postgres://u:p@localhost:5432/bar\n",
+    )
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--pgclirc", str(cfg), "--list-dsn"])
+    assert result.exit_code == 0
+    assert "foo : postgres://u:p@localhost:5432/foo" in result.output
+    assert "bar : postgres://u:p@localhost:5432/bar" in result.output
+
+
+def test_dsn_alias_resolves(isolate_config, monkeypatch):
+    cfg = write_config(
+        isolate_config,
+        "[alias_dsn]\nfoo = postgres://u:p@localhost:5432/foo\n",
+    )
+    captured = {}
+
+    def fake_connect(self, *args, **kwargs):
+        # connect_uri() parses the alias URI and calls connect() with the
+        # resolved parts, so recording them proves the alias was found.
+        captured.update(kwargs)
+
+        class DummyExec:
+            def run(self, cmd):
+                return []
+
+            def get_timezone(self):
+                return "UTC"
+
+            def set_timezone(self, *a, **k):
+                pass
+
+        self.pgexecute = DummyExec()
+
+    monkeypatch.setattr(PGCli, "connect", fake_connect)
+
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--pgclirc", str(cfg), "-D", "foo", "--ping"])
+    assert result.exit_code == 0
+    assert "Could not find a DSN" not in result.output
+    assert captured.get("database") == "foo"
+    assert captured.get("host") == "localhost"
+
+
+def test_dsn_alias_missing(isolate_config):
+    cfg = write_config(
+        isolate_config,
+        "[alias_dsn]\nfoo = postgres://u:p@localhost:5432/foo\n",
+    )
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--pgclirc", str(cfg), "-D", "does-not-exist"])
+    assert result.exit_code == 1
+    assert "Could not find a DSN with alias does-not-exist" in result.output