Add function_abi_now_unwind lint and fix function_abi_no_longer_unwind. (#1061)

The `function_abi_no_longer_unwind` lint had false-positives since it
failed to connect the baseline and current functions by their import
paths.

Author: obi1kenobi

src/lints/function_abi_no_longer_unwind.ron

@@ -16,11 +16,16 @@ SemverQuery(
                         name @output
 
                         new_abi_: abi {
-                            name @tag
+                            name @tag(name: "abi")
                             raw_name @output
                             unwind @filter(op: "!=", value: ["$true"])
                         }
 
+                        importable_path {
+                            path @output @tag
+                            public_api @filter(op: "=", value: ["$true"])
+                        }
+
                         span_: span @optional {
                             filename @output
                             begin_line @output
@@ -34,10 +39,15 @@ SemverQuery(
                         visibility_limit @filter(op: "=", value: ["$public"])
 
                         abi_: abi {
-                            name @filter(op: "=", value: ["%name"])
+                            name @filter(op: "=", value: ["%abi"])
                             raw_name @output
                             unwind @filter(op: "=", value: ["$true"])
                         }
+
+                        importable_path {
+                            path @filter(op: "=", value: ["%path"])
+                            public_api @filter(op: "=", value: ["$true"])
+                        }
                     }
                 }
             }

src/lints/function_abi_now_unwind.ron

@@ -0,0 +1,62 @@
+SemverQuery(
+    id: "function_abi_now_unwind",
+    human_readable_name: "function abi is now unwind-capable",
+    description: "A pub fn changed from an non-unwind ABI to the same-named ABI with unwind ability. This change might not be compatible with callers of this function, since they may not expect unwinding to happen here.",
+    required_update: Major,
+    lint_level: Deny,
+    reference_link: Some("https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html"),
+    query: r#"
+    {
+        CrateDiff {
+            current {
+                item {
+                    ... on Function {
+                        visibility_limit @filter(op: "=", value: ["$public"])
+
+                        name @output
+
+                        new_abi_: abi {
+                            name @tag(name: "abi")
+                            raw_name @output
+                            unwind @filter(op: "=", value: ["$true"])
+                        }
+
+                        importable_path {
+                            path @output @tag
+                            public_api @filter(op: "=", value: ["$true"])
+                        }
+
+                        span_: span @optional {
+                            filename @output
+                            begin_line @output
+                        }
+                    }
+                }
+            }
+            baseline {
+                item {
+                    ... on Function {
+                        visibility_limit @filter(op: "=", value: ["$public"])
+
+                        abi_: abi {
+                            name @filter(op: "=", value: ["%abi"])
+                            raw_name @output
+                            unwind @filter(op: "!=", value: ["$true"])
+                        }
+
+                        importable_path {
+                            path @filter(op: "=", value: ["%path"])
+                            public_api @filter(op: "=", value: ["$true"])
+                        }
+                    }
+                }
+            }
+        }
+    }"#,
+    arguments: {
+        "public": "public",
+        "true": true,
+    },
+    error_message: "A pub fn changed from a non-unwind ABI to the same-named ABI with unwind ability. This change might not be compatible with callers of this function, since they may not expect unwinding to happen here.",
+    per_result_error_template: Some("{{join \"::\" path}} changed ABI from {{abi_raw_name}} to {{new_abi_raw_name}} in {{span_filename}}:{{span_begin_line}}"),
+)

src/query.rs

@@ -1152,6 +1152,7 @@ add_lints!(
     feature_missing,
     feature_not_enabled_by_default,
     function_abi_no_longer_unwind,
+    function_abi_now_unwind,
     function_changed_abi,
     function_const_removed,
     function_export_name_changed,

test_crates/function_abi_no_longer_unwind/new/src/lib.rs

@@ -1 +1,7 @@
 pub extern "C" fn unwind_function_becomes_non_unwind() {}
+
+pub extern "C-unwind" fn non_unwind_function_becomes_unwind() {}
+
+pub extern "C" fn non_unwind_function_unchanged() {}
+
+pub extern "C-unwind" fn unwind_function_unchanged() {}

test_crates/function_abi_no_longer_unwind/old/src/lib.rs

@@ -1 +1,7 @@
 pub extern "C-unwind" fn unwind_function_becomes_non_unwind() {}
+
+pub extern "C" fn non_unwind_function_becomes_unwind() {}
+
+pub extern "C" fn non_unwind_function_unchanged() {}
+
+pub extern "C-unwind" fn unwind_function_unchanged() {}

test_outputs/query_execution/function_abi_no_longer_unwind.snap

@@ -1,13 +1,18 @@
 ---
 source: src/query.rs
 expression: "&query_execution_results"
+snapshot_kind: text
 ---
 {
   "./test_crates/function_abi_no_longer_unwind/": [
     {
       "abi_raw_name": String("C-unwind"),
       "name": String("unwind_function_becomes_non_unwind"),
       "new_abi_raw_name": String("C"),
+      "path": List([
+        String("function_abi_no_longer_unwind"),
+        String("unwind_function_becomes_non_unwind"),
+      ]),
       "span_begin_line": Uint64(1),
       "span_filename": String("src/lib.rs"),
     },

test_outputs/query_execution/function_abi_now_unwind.snap

@@ -0,0 +1,20 @@
+---
+source: src/query.rs
+expression: "&query_execution_results"
+snapshot_kind: text
+---
+{
+  "./test_crates/function_abi_no_longer_unwind/": [
+    {
+      "abi_raw_name": String("C"),
+      "name": String("non_unwind_function_becomes_unwind"),
+      "new_abi_raw_name": String("C-unwind"),
+      "path": List([
+        String("function_abi_no_longer_unwind"),
+        String("non_unwind_function_becomes_unwind"),
+      ]),
+      "span_begin_line": Uint64(3),
+      "span_filename": String("src/lib.rs"),
+    },
+  ],
+}