feat(json_analyze): implement noEmptyObjectKeys

.changeset/wild-dolls-talk.md

@@ -0,0 +1,13 @@
+---
+"@biomejs/biome": patch
+---
+
+Added the nursery rule [`noEmptyObjectKeys`](https://biomejs.dev/linter/rules/no-empty-object-keys/), which disallows the use of empty keys in JSON objects.
+
+**Invalid:**
+
+```json
+{
+  "": "value"
+}
+```

crates/biome_json_analyze/Cargo.toml

@@ -21,6 +21,7 @@ name    = "json_analyzer"
 biome_analyze        = { workspace = true }
 biome_analyze_macros = { workspace = true }
 biome_console        = { workspace = true }
+biome_deserialize    = { workspace = true }
 biome_diagnostics    = { workspace = true }
 biome_json_factory   = { workspace = true }
 biome_json_syntax    = { workspace = true }

crates/biome_json_analyze/src/lint/nursery/no_empty_object_keys.rs

@@ -0,0 +1,101 @@
+use biome_analyze::{
+    Ast, Rule, RuleDiagnostic, RuleSource, context::RuleContext, declare_lint_rule,
+};
+use biome_console::markup;
+use biome_deserialize::json::unescape_json_string;
+use biome_json_syntax::JsonMemberName;
+use biome_rowan::AstNode;
+use biome_rule_options::no_empty_object_keys::NoEmptyObjectKeysOptions;
+
+declare_lint_rule! {
+    /// Disallow empty keys in JSON objects.
+    ///
+    /// In JSON, using empty keys (keys that are empty strings or contain only whitespace) can lead to accessibility and maintenance issues.
+    /// While technically valid in JSON, empty keys make objects harder to read, can cause confusion when debugging, and may create problems with some JSON parsers or processors.
+    /// Additionally, empty keys often indicate mistakes or oversights in the processes.
+    ///
+    /// ## Examples
+    ///
+    /// ### Invalid
+    ///
+    /// ```json,expect_diagnostic
+    /// {
+    ///   "": "value"
+    /// }
+    /// ```
+    ///
+    /// ```json,expect_diagnostic
+    /// {
+    ///   "validKey": "value",
+    ///   "": "another value"
+    /// }
+    /// ```
+    ///
+    /// ```json,expect_diagnostic
+    /// {
+    ///   " ": "space as key"
+    /// }
+    /// ```
+    ///
+    /// ```json,expect_diagnostic
+    /// {
+    ///   "\t": "tab as key"
+    /// }
+    /// ```
+    ///
+    /// ```json,expect_diagnostic
+    /// {
+    ///   "\n": "newline as key"
+    /// }
+    /// ```
+    ///
+    /// ### Valid
+    ///
+    /// ```json
+    /// {
+    ///   "key": "value"
+    /// }
+    /// ```
+    ///
+    pub NoEmptyObjectKeys {
+        version: "next",
+        name: "noEmptyObjectKeys",
+        language: "json",
+        recommended: false,
+        sources: &[RuleSource::EslintJson("no-empty-keys").same()],
+    }
+}
+
+impl Rule for NoEmptyObjectKeys {
+    type Query = Ast<JsonMemberName>;
+    type State = ();
+    type Signals = Option<Self::State>;
+    type Options = NoEmptyObjectKeysOptions;
+
+    fn run(ctx: &RuleContext<Self>) -> Self::Signals {
+        let node = ctx.query();
+        let value = node.inner_string_text().ok()?;
+        let binding = unescape_json_string(value);
+        if binding.trim().is_empty() {
+            return Some(());
+        }
+
+        None
+    }
+
+    fn diagnostic(ctx: &RuleContext<Self>, _state: &Self::State) -> Option<RuleDiagnostic> {
+        let span = ctx.query().range();
+        Some(
+            RuleDiagnostic::new(
+                rule_category!(),
+                span,
+                markup! {
+                    "Unexpected empty object key."
+                },
+            )
+            .note(markup! {
+                "Empty keys often cause confusion and may cause issues with parsers or processors. Either remove this property or provide a meaningful key name."
+            }),
+        )
+    }
+}

crates/biome_json_analyze/tests/specs/nursery/noEmptyObjectKeys/invalid.json

@@ -0,0 +1,7 @@
+{
+  "": "another value",
+  " ": "space as key",
+  "\t": "tab as key",
+  "\n": "newline as key",
+  "\n\n\n": "multi newline as key"
+}

crates/biome_json_analyze/tests/specs/nursery/noEmptyObjectKeys/invalid.json.snap

@@ -0,0 +1,110 @@
+---
+source: crates/biome_json_analyze/tests/spec_tests.rs
+expression: invalid.json
+---
+# Input
+```json
+{
+  "": "another value",
+  " ": "space as key",
+  "\t": "tab as key",
+  "\n": "newline as key",
+  "\n\n\n": "multi newline as key"
+}
+
+```
+
+# Diagnostics
+```
+invalid.json:2:3 lint/nursery/noEmptyObjectKeys ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Unexpected empty object key.
+
+    1 │ {
+  > 2 │   "": "another value",
+      │   ^^
+    3 │   " ": "space as key",
+    4 │   "\t": "tab as key",
+
+  i Empty keys often cause confusion and may cause issues with parsers or processors. Either remove this property or provide a meaningful key name.
+
+  i This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
+
+
+```
+
+```
+invalid.json:3:3 lint/nursery/noEmptyObjectKeys ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Unexpected empty object key.
+
+    1 │ {
+    2 │   "": "another value",
+  > 3 │   " ": "space as key",
+      │   ^^^
+    4 │   "\t": "tab as key",
+    5 │   "\n": "newline as key",
+
+  i Empty keys often cause confusion and may cause issues with parsers or processors. Either remove this property or provide a meaningful key name.
+
+  i This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
+
+
+```
+
+```
+invalid.json:4:3 lint/nursery/noEmptyObjectKeys ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Unexpected empty object key.
+
+    2 │   "": "another value",
+    3 │   " ": "space as key",
+  > 4 │   "\t": "tab as key",
+      │   ^^^^
+    5 │   "\n": "newline as key",
+    6 │   "\n\n\n": "multi newline as key"
+
+  i Empty keys often cause confusion and may cause issues with parsers or processors. Either remove this property or provide a meaningful key name.
+
+  i This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
+
+
+```
+
+```
+invalid.json:5:3 lint/nursery/noEmptyObjectKeys ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Unexpected empty object key.
+
+    3 │   " ": "space as key",
+    4 │   "\t": "tab as key",
+  > 5 │   "\n": "newline as key",
+      │   ^^^^
+    6 │   "\n\n\n": "multi newline as key"
+    7 │ }
+
+  i Empty keys often cause confusion and may cause issues with parsers or processors. Either remove this property or provide a meaningful key name.
+
+  i This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
+
+
+```
+
+```
+invalid.json:6:3 lint/nursery/noEmptyObjectKeys ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i Unexpected empty object key.
+
+    4 │   "\t": "tab as key",
+    5 │   "\n": "newline as key",
+  > 6 │   "\n\n\n": "multi newline as key"
+      │   ^^^^^^^^
+    7 │ }
+    8 │ 
+
+  i Empty keys often cause confusion and may cause issues with parsers or processors. Either remove this property or provide a meaningful key name.
+
+  i This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
+
+
+```

crates/biome_json_analyze/tests/specs/nursery/noEmptyObjectKeys/valid.json

@@ -0,0 +1,7 @@
+{
+  "key1": "value1",
+  "key2": {
+    "nestedKey": "nested value",
+    "   nestedKey \n\t  ": "nested value"
+  }
+}

crates/biome_json_analyze/tests/specs/nursery/noEmptyObjectKeys/valid.json.snap

@@ -0,0 +1,15 @@
+---
+source: crates/biome_json_analyze/tests/spec_tests.rs
+expression: valid.json
+---
+# Input
+```json
+{
+  "key1": "value1",
+  "key2": {
+    "nestedKey": "nested value",
+    "   nestedKey \n\t  ": "nested value"
+  }
+}
+
+```

crates/biome_rule_options/src/lib.rs

@@ -84,6 +84,7 @@ pub mod no_empty_block;
 pub mod no_empty_block_statements;
 pub mod no_empty_character_class_in_regex;
 pub mod no_empty_interface;
+pub mod no_empty_object_keys;
 pub mod no_empty_pattern;
 pub mod no_empty_source;
 pub mod no_empty_type_parameters;

crates/biome_rule_options/src/no_empty_object_keys.rs

@@ -0,0 +1,6 @@
+use biome_deserialize_macros::{Deserializable, Merge};
+use serde::{Deserialize, Serialize};
+#[derive(Default, Clone, Debug, Deserialize, Deserializable, Merge, Eq, PartialEq, Serialize)]
+#[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
+#[serde(rename_all = "camelCase", deny_unknown_fields, default)]
+pub struct NoEmptyObjectKeysOptions {}