Add allow-invalid configuration option for disallowed_* to the documentation (rust-lang#14845)

Close rust-lang/rust-clippy#14836

changelog: none

Author: samueltardieu

book/src/lint_configuration.md

@@ -488,6 +488,13 @@ The maximum cognitive complexity a function can have
 ## `disallowed-macros`
 The list of disallowed macros, written as fully qualified paths.
 
+**Fields:**
+- `path` (required): the fully qualified path to the macro that should be disallowed
+- `reason` (optional): explanation why this macro is disallowed
+- `replacement` (optional): suggested alternative macro
+- `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
+  if the path doesn't exist, instead of emitting an error
+
 **Default Value:** `[]`
 
 ---
@@ -498,6 +505,13 @@ The list of disallowed macros, written as fully qualified paths.
 ## `disallowed-methods`
 The list of disallowed methods, written as fully qualified paths.
 
+**Fields:**
+- `path` (required): the fully qualified path to the method that should be disallowed
+- `reason` (optional): explanation why this method is disallowed
+- `replacement` (optional): suggested alternative method
+- `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
+  if the path doesn't exist, instead of emitting an error
+
 **Default Value:** `[]`
 
 ---
@@ -520,6 +534,13 @@ default configuration of Clippy. By default, any configuration will replace the
 ## `disallowed-types`
 The list of disallowed types, written as fully qualified paths.
 
+**Fields:**
+- `path` (required): the fully qualified path to the type that should be disallowed
+- `reason` (optional): explanation why this type is disallowed
+- `replacement` (optional): suggested alternative type
+- `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
+  if the path doesn't exist, instead of emitting an error
+
 **Default Value:** `[]`
 
 ---

clippy_config/src/conf.rs

@@ -575,10 +575,24 @@ define_Conf! {
     #[conf_deprecated("Please use `cognitive-complexity-threshold` instead", cognitive_complexity_threshold)]
     cyclomatic_complexity_threshold: u64 = 25,
     /// The list of disallowed macros, written as fully qualified paths.
+    ///
+    /// **Fields:**
+    /// - `path` (required): the fully qualified path to the macro that should be disallowed
+    /// - `reason` (optional): explanation why this macro is disallowed
+    /// - `replacement` (optional): suggested alternative macro
+    /// - `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
+    ///   if the path doesn't exist, instead of emitting an error
     #[disallowed_paths_allow_replacements = true]
     #[lints(disallowed_macros)]
     disallowed_macros: Vec<DisallowedPath> = Vec::new(),
     /// The list of disallowed methods, written as fully qualified paths.
+    ///
+    /// **Fields:**
+    /// - `path` (required): the fully qualified path to the method that should be disallowed
+    /// - `reason` (optional): explanation why this method is disallowed
+    /// - `replacement` (optional): suggested alternative method
+    /// - `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
+    ///   if the path doesn't exist, instead of emitting an error
     #[disallowed_paths_allow_replacements = true]
     #[lints(disallowed_methods)]
     disallowed_methods: Vec<DisallowedPath> = Vec::new(),
@@ -588,6 +602,13 @@ define_Conf! {
     #[lints(disallowed_names)]
     disallowed_names: Vec<String> = DEFAULT_DISALLOWED_NAMES.iter().map(ToString::to_string).collect(),
     /// The list of disallowed types, written as fully qualified paths.
+    ///
+    /// **Fields:**
+    /// - `path` (required): the fully qualified path to the type that should be disallowed
+    /// - `reason` (optional): explanation why this type is disallowed
+    /// - `replacement` (optional): suggested alternative type
+    /// - `allow-invalid` (optional, `false` by default): when set to `true`, it will ignore this entry
+    ///   if the path doesn't exist, instead of emitting an error
     #[disallowed_paths_allow_replacements = true]
     #[lints(disallowed_types)]
     disallowed_types: Vec<DisallowedPath> = Vec::new(),

clippy_lints/src/disallowed_macros.rs

@@ -39,6 +39,9 @@ declare_clippy_lint! {
     ///     # When using an inline table, can add a `reason` for why the macro
     ///     # is disallowed.
     ///     { path = "serde::Serialize", reason = "no serializing" },
+    ///     # This would normally error if the path is incorrect, but with `allow-invalid` = `true`,
+    ///     # it will be silently ignored
+    ///     { path = "std::invalid_macro", reason = "use alternative instead", allow-invalid = true }
     /// ]
     /// ```
     /// ```no_run

clippy_lints/src/disallowed_methods.rs

@@ -34,6 +34,9 @@ declare_clippy_lint! {
     ///     { path = "std::vec::Vec::leak", reason = "no leaking memory" },
     ///     # Can also add a `replacement` that will be offered as a suggestion.
     ///     { path = "std::sync::Mutex::new", reason = "prefer faster & simpler non-poisonable mutex", replacement = "parking_lot::Mutex::new" },
+    ///     # This would normally error if the path is incorrect, but with `allow-invalid` = `true`,
+    ///     # it will be silently ignored
+    ///     { path = "std::fs::InvalidPath", reason = "use alternative instead", allow-invalid = true },
     /// ]
     /// ```
     ///

clippy_lints/src/disallowed_types.rs

@@ -35,6 +35,9 @@ declare_clippy_lint! {
     ///     { path = "std::net::Ipv4Addr", reason = "no IPv4 allowed" },
     ///     # Can also add a `replacement` that will be offered as a suggestion.
     ///     { path = "std::sync::Mutex", reason = "prefer faster & simpler non-poisonable mutex", replacement = "parking_lot::Mutex" },
+    ///     # This would normally error if the path is incorrect, but with `allow-invalid` = `true`,
+    ///     # it will be silently ignored
+    ///     { path = "std::invalid::Type", reason = "use alternative instead", allow-invalid = true }
     /// ]
     /// ```
     ///