From 965d62aadec125662060a70ec970c721fda5d13e Mon Sep 17 00:00:00 2001
From: Malena Gruevski <45406876+malenaohl@users.noreply.github.com>
Date: Sat, 7 Dec 2024 17:57:05 -0500
Subject: [PATCH] Add lint attribute_proc_macro_missing (#1026)

Addresses a checkbox in
/~https://github.com/obi1kenobi/cargo-semver-checks/issues/946
---
 src/lints/attribute_proc_macro_missing.ron    | 40 +++++++++++++++++++
 src/query.rs                                  |  1 +
 .../new/Cargo.toml                            | 10 +++++
 .../new/src/lib.rs                            | 12 ++++++
 .../old/Cargo.toml                            | 10 +++++
 .../old/src/lib.rs                            | 18 +++++++++
 .../attribute_proc_macro_missing.snap         | 14 +++++++
 7 files changed, 105 insertions(+)
 create mode 100644 src/lints/attribute_proc_macro_missing.ron
 create mode 100644 test_crates/attribute_proc_macro_missing/new/Cargo.toml
 create mode 100644 test_crates/attribute_proc_macro_missing/new/src/lib.rs
 create mode 100644 test_crates/attribute_proc_macro_missing/old/Cargo.toml
 create mode 100644 test_crates/attribute_proc_macro_missing/old/src/lib.rs
 create mode 100644 test_outputs/query_execution/attribute_proc_macro_missing.snap

diff --git a/src/lints/attribute_proc_macro_missing.ron b/src/lints/attribute_proc_macro_missing.ron
new file mode 100644
index 00000000..d20e807b
--- /dev/null
+++ b/src/lints/attribute_proc_macro_missing.ron
@@ -0,0 +1,40 @@
+SemverQuery(
+    id: "attribute_proc_macro_missing",
+    human_readable_name: "attribute proc macro removed",
+    description: "An attribute proc macro that previously existed is no longer available.",
+    required_update: Major,
+    lint_level: Deny,
+    reference_link: Some("https://doc.rust-lang.org/reference/procedural-macros.html#attribute-macros"),
+    query: r#"
+    {
+        CrateDiff {
+            baseline {
+                item {
+                    ... on AttributeProcMacro {
+                        visibility_limit @filter(op: "=", value: ["$public"])
+                        name @output @tag
+                        span_: span @optional {
+                            filename @output
+                            begin_line @output
+                        }
+                    }
+                }
+            }
+            current @fold @transform(op: "count") @filter(op: "=", value: ["$zero"]) {
+                item {
+                    ... on AttributeProcMacro {
+                        visibility_limit @filter(op: "=", value: ["$public"])
+                        name @filter(op: "=", value: ["%name"])
+                    }
+                }
+            }
+        }
+    }"#,
+    arguments: {
+        "public": "public",
+        "zero": 0,
+    },
+    error_message: "A previously available attribute macro has been removed, breaking code that uses attribute syntax on annotated items.",
+    per_result_error_template: Some("macro #[{{name}}] in {{span_filename}}:{{span_begin_line}}"),
+    witness: None,
+)
diff --git a/src/query.rs b/src/query.rs
index c20f5178..81be133f 100644
--- a/src/query.rs
+++ b/src/query.rs
@@ -1048,6 +1048,7 @@ macro_rules! add_lints {
 // The following add_lints! invocation is programmatically edited by scripts/make_new_lint.sh
 // If you must manually edit it, be sure to read the "Requirements" comments in that script first
 add_lints!(
+    attribute_proc_macro_missing,
     auto_trait_impl_removed,
     constructible_struct_adds_field,
     constructible_struct_adds_private_field,
diff --git a/test_crates/attribute_proc_macro_missing/new/Cargo.toml b/test_crates/attribute_proc_macro_missing/new/Cargo.toml
new file mode 100644
index 00000000..182bcd10
--- /dev/null
+++ b/test_crates/attribute_proc_macro_missing/new/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+publish = false
+name = "attribute_proc_macro_missing"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[dependencies]
diff --git a/test_crates/attribute_proc_macro_missing/new/src/lib.rs b/test_crates/attribute_proc_macro_missing/new/src/lib.rs
new file mode 100644
index 00000000..8d71dc01
--- /dev/null
+++ b/test_crates/attribute_proc_macro_missing/new/src/lib.rs
@@ -0,0 +1,12 @@
+use proc_macro::TokenStream;
+
+// Keep other macro types to verify specific detection
+#[proc_macro]
+pub fn sql(_item: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+#[proc_macro_derive(MyDerive)]
+pub fn my_derive(_item: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
diff --git a/test_crates/attribute_proc_macro_missing/old/Cargo.toml b/test_crates/attribute_proc_macro_missing/old/Cargo.toml
new file mode 100644
index 00000000..182bcd10
--- /dev/null
+++ b/test_crates/attribute_proc_macro_missing/old/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+publish = false
+name = "attribute_proc_macro_missing"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[dependencies]
diff --git a/test_crates/attribute_proc_macro_missing/old/src/lib.rs b/test_crates/attribute_proc_macro_missing/old/src/lib.rs
new file mode 100644
index 00000000..9632e9d8
--- /dev/null
+++ b/test_crates/attribute_proc_macro_missing/old/src/lib.rs
@@ -0,0 +1,18 @@
+use proc_macro::TokenStream;
+
+#[proc_macro_attribute]
+pub fn logging(_attr: TokenStream, item: TokenStream) -> TokenStream {
+    item
+}
+
+// Keep this to verify we don't trigger on function-like macros
+#[proc_macro]
+pub fn sql(_item: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
+
+// Keep this to verify we don't trigger on derive macros
+#[proc_macro_derive(MyDerive)]
+pub fn my_derive(_item: TokenStream) -> TokenStream {
+    TokenStream::new()
+}
diff --git a/test_outputs/query_execution/attribute_proc_macro_missing.snap b/test_outputs/query_execution/attribute_proc_macro_missing.snap
new file mode 100644
index 00000000..57ed9eb8
--- /dev/null
+++ b/test_outputs/query_execution/attribute_proc_macro_missing.snap
@@ -0,0 +1,14 @@
+---
+source: src/query.rs
+expression: "&query_execution_results"
+snapshot_kind: text
+---
+{
+  "./test_crates/attribute_proc_macro_missing/": [
+    {
+      "name": String("logging"),
+      "span_begin_line": Uint64(4),
+      "span_filename": String("src/lib.rs"),
+    },
+  ],
+}