fix: disallow empty hosts on _UriData and fetch-libs on build

.jujuignore

@@ -0,0 +1 @@
+tests/

charmcraft.yaml

@@ -27,6 +27,7 @@ parts:
     charm-requirements: ["requirements.txt"]
     override-build: |
       just requirements
+      charmcraft fetch-libs
       craftctl default
 
 charm-libs:

lib/charms/filesystem_client/v0/filesystem_info.py

@@ -138,7 +138,7 @@ def _on_start(self, event: ops.StartEvent) -> None:
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 1
+LIBPATCH = 2
 
 _logger = logging.getLogger(__name__)
 
@@ -217,12 +217,17 @@ def __init__(
     ) -> None:
         if not scheme:
             raise FilesystemInfoError("scheme cannot be empty")
-        if len(hosts) == 0:
+        str_hosts = []
+        for host in hosts:
+            if not host:
+                raise FilesystemInfoError(f"invalid host `{host}`")
+            str_hosts.append(str(host))
+        if len(str_hosts) == 0:
             raise FilesystemInfoError("list of hosts cannot be empty")
 
         # Strictly convert to the required types to avoid passing through weird data.
         object.__setattr__(self, "scheme", str(scheme))
-        object.__setattr__(self, "hosts", [str(host) for host in hosts])
+        object.__setattr__(self, "hosts", str_hosts)
         object.__setattr__(self, "user", str(user) if user else "")
         object.__setattr__(self, "path", str(path) if path else "/")
         object.__setattr__(
@@ -245,10 +250,14 @@ def from_uri(cls, uri: str) -> "_UriData":
         hosts = hostname[1:-1].split(",")
         path = unquote(result.path or "")
         try:
-            options = {
-                key: ",".join(values)
-                for key, values in parse_qs(result.query, strict_parsing=True).items()
-            }
+            options = (
+                {
+                    key: ",".join(values)
+                    for key, values in parse_qs(result.query, strict_parsing=True).items()
+                }
+                if result.query
+                else {}
+            )
         except ValueError:
             raise ParseUriError(f"invalid options for endpoint `{uri}`")
         try:
@@ -378,7 +387,7 @@ def to_uri(self, _model: Model) -> str:
         except AddressValueError:
             host = self.hostname
 
-        hosts = [host + f":{self.port}" if self.port else ""]
+        hosts = [host + (f":{self.port}" if self.port else "")]
 
         return str(_UriData(scheme=self.filesystem_type(), hosts=hosts, path=self.path))
 

tests/integration/server/lib/charms/filesystem_client/v0/filesystem_info.py

@@ -138,7 +138,7 @@ def _on_start(self, event: ops.StartEvent) -> None:
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 1
+LIBPATCH = 2
 
 _logger = logging.getLogger(__name__)
 
@@ -217,12 +217,17 @@ def __init__(
     ) -> None:
         if not scheme:
             raise FilesystemInfoError("scheme cannot be empty")
-        if len(hosts) == 0:
+        str_hosts = []
+        for host in hosts:
+            if not host:
+                raise FilesystemInfoError(f"invalid host `{host}`")
+            str_hosts.append(str(host))
+        if len(str_hosts) == 0:
             raise FilesystemInfoError("list of hosts cannot be empty")
 
         # Strictly convert to the required types to avoid passing through weird data.
         object.__setattr__(self, "scheme", str(scheme))
-        object.__setattr__(self, "hosts", [str(host) for host in hosts])
+        object.__setattr__(self, "hosts", str_hosts)
         object.__setattr__(self, "user", str(user) if user else "")
         object.__setattr__(self, "path", str(path) if path else "/")
         object.__setattr__(
@@ -245,10 +250,14 @@ def from_uri(cls, uri: str) -> "_UriData":
         hosts = hostname[1:-1].split(",")
         path = unquote(result.path or "")
         try:
-            options = {
-                key: ",".join(values)
-                for key, values in parse_qs(result.query, strict_parsing=True).items()
-            }
+            options = (
+                {
+                    key: ",".join(values)
+                    for key, values in parse_qs(result.query, strict_parsing=True).items()
+                }
+                if result.query
+                else {}
+            )
         except ValueError:
             raise ParseUriError(f"invalid options for endpoint `{uri}`")
         try:
@@ -378,7 +387,7 @@ def to_uri(self, _model: Model) -> str:
         except AddressValueError:
             host = self.hostname
 
-        hosts = [host + f":{self.port}" if self.port else ""]
+        hosts = [host + (f":{self.port}" if self.port else "")]
 
         return str(_UriData(scheme=self.filesystem_type(), hosts=hosts, path=self.path))