Do not touch module with #![rustfmt::skip] (#4297)

Author: topecongiro

Diff for: src/formatting.rs

@@ -2,7 +2,7 @@
 
 use std::time::{Duration, Instant};
 
-use rustc_ast::ast;
+use rustc_ast::{ast, attr::HasAttrs};
 use rustc_span::symbol;
 
 pub(crate) use syntux::session::ParseSess;
@@ -14,7 +14,7 @@ use crate::formatting::{
     newline_style::apply_newline_style,
     report::NonFormattedRange,
     syntux::parser::{DirectoryOwnership, Parser, ParserError},
-    utils::count_newlines,
+    utils::{contains_skip, count_newlines},
     visitor::FmtVisitor,
 };
 use crate::{
@@ -129,6 +129,10 @@ fn format_project(
         if (!operation_setting.recursive && path != &main_file) || should_ignore {
             continue;
         }
+        if contains_skip(module.attrs()) {
+            continue;
+        }
+
         should_emit_verbose(input_is_stdin, operation_setting.verbosity, || {
             println!("Formatting {}", path)
         });

Diff for: src/formatting/visitor.rs

@@ -967,12 +967,14 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
 
     pub(crate) fn format_separate_mod(&mut self, m: &Module<'_>, end_pos: BytePos) {
         self.block_indent = Indent::empty();
-        if self.visit_attrs(m.attrs(), ast::AttrStyle::Inner) {
-            self.push_skipped_with_span(m.attrs(), m.as_ref().inner, m.as_ref().inner);
-        } else {
-            self.walk_mod_items(m.as_ref());
-            self.format_missing_with_indent(end_pos);
-        }
+        let skipped = self.visit_attrs(m.attrs(), ast::AttrStyle::Inner);
+        assert!(
+            !skipped,
+            "Skipping module must be handled before reaching this line.",
+        );
+
+        self.walk_mod_items(m.as_ref());
+        self.format_missing_with_indent(end_pos);
     }
 
     pub(crate) fn skip_empty_lines(&mut self, end_pos: BytePos) {

Diff for: src/test/configuration_snippet.rs

@@ -190,9 +190,19 @@ impl ConfigCodeBlock {
         }
 
         let report = report.unwrap();
-        let result = report.format_result().next().unwrap();
-        let text = result.1.formatted_text();
-        !self.formatted_has_diff(text)
+        let result = report.format_result().next();
+
+        match result {
+            Some(result) => {
+                let text = result.1.formatted_text();
+                !self.formatted_has_diff(text)
+            }
+            None => {
+                // The format report may be empty if the code block contains `#![rustfmt::skip]`.
+                // In that case, we just return true.
+                true
+            }
+        }
     }
 
     // Extract a code block from the iterator. Behavior:

Diff for: tests/target/skip/skip-with-trailing-comma.rs

@@ -0,0 +1,10 @@
+#![rustfmt::skip]
+
+fn myfunc1()
+{
+    println!("hi");      // yes I want my comments here
+} // keep this comment here too
+
+fn myfunc2() {
+    println!("bye");        // i want it that way
+} // tell me why