Merge pull request rust-lang#3454 from rchaser53/issue-3434

add new attribute rustfmt::skip::macros

Author: scampi

README.md

@@ -179,6 +179,18 @@ needs to be specified in `rustfmt.toml`, e.g., with `edition = "2018"`.
 ## Tips
 
 * For things you do not want rustfmt to mangle, use `#[rustfmt::skip]`
+* To prevent rustfmt from formatting a macro,
+  use `#[rustfmt::skip::macros(target_macro_name)]`
+
+  Example:
+
+    ```rust
+    #[rustfmt::skip::macros(html)]
+    fn main() {
+        let macro_result1 = html! { <div>
+    Hello</div>
+        }.to_string();
+    ```
 * When you run rustfmt, place a file named `rustfmt.toml` or `.rustfmt.toml` in
   target file directory or its parents to override the default settings of
   rustfmt. You can generate a file containing the default configuration with

src/formatting.rs

@@ -15,6 +15,7 @@ use syntax::source_map::{FilePathMapping, SourceMap, Span, DUMMY_SP};
 use crate::comment::{CharClasses, FullCodeCharKind};
 use crate::config::{Config, FileName, Verbosity};
 use crate::issues::BadIssueSeeker;
+use crate::utils::{count_newlines, get_skip_macro_names};
 use crate::visitor::{FmtVisitor, SnippetProvider};
 use crate::{modules, source_file, ErrorKind, FormatReport, Input, Session};
 
@@ -153,6 +154,10 @@ impl<'a, T: FormatHandler + 'a> FormatContext<'a, T> {
             &snippet_provider,
             self.report.clone(),
         );
+        visitor
+            .skip_macro_names
+            .borrow_mut()
+            .append(&mut get_skip_macro_names(&self.krate.attrs));
 
         // Format inner attributes if available.
         if !self.krate.attrs.is_empty() && is_root {
@@ -168,10 +173,7 @@ impl<'a, T: FormatHandler + 'a> FormatContext<'a, T> {
             visitor.format_separate_mod(module, &*source_file);
         };
 
-        debug_assert_eq!(
-            visitor.line_number,
-            crate::utils::count_newlines(&visitor.buffer)
-        );
+        debug_assert_eq!(visitor.line_number, count_newlines(&visitor.buffer));
 
         // For some reason, the source_map does not include terminating
         // newlines so we must add one on for each file. This is sad.

src/lib.rs

@@ -94,7 +94,7 @@ pub enum ErrorKind {
     /// Used deprecated skip attribute.
     #[fail(display = "`rustfmt_skip` is deprecated; use `rustfmt::skip`")]
     DeprecatedAttr,
-    /// Used a rustfmt:: attribute other than skip.
+    /// Used a rustfmt:: attribute other than skip or skip::macros.
     #[fail(display = "invalid attribute")]
     BadAttr,
     /// An io error during reading or writing.

src/macros.rs

@@ -208,12 +208,21 @@ pub fn rewrite_macro(
     shape: Shape,
     position: MacroPosition,
 ) -> Option<String> {
-    let guard = InsideMacroGuard::inside_macro_context(context);
-    let result = rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
-    if result.is_none() {
-        context.macro_rewrite_failure.replace(true);
+    let should_skip = context
+        .skip_macro_names
+        .borrow()
+        .contains(&context.snippet(mac.node.path.span).to_owned());
+    if should_skip {
+        None
+    } else {
+        let guard = InsideMacroGuard::inside_macro_context(context);
+        let result =
+            rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
+        if result.is_none() {
+            context.macro_rewrite_failure.replace(true);
+        }
+        result
     }
-    result
 }
 
 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {

src/rewrite.rs

@@ -39,6 +39,7 @@ pub struct RewriteContext<'a> {
     // Used for `format_snippet`
     pub(crate) macro_rewrite_failure: RefCell<bool>,
     pub(crate) report: FormatReport,
+    pub skip_macro_names: RefCell<Vec<String>>,
 }
 
 impl<'a> RewriteContext<'a> {

src/test/mod.rs

@@ -22,6 +22,7 @@ const SKIP_FILE_WHITE_LIST: &[&str] = &[
     // We want to make sure that the `skip_children` is correctly working,
     // so we do not want to test this file directly.
     "configs/skip_children/foo/mod.rs",
+    "issue-3434/no_entry.rs",
 ];
 
 fn is_file_skip(path: &Path) -> bool {

src/utils.rs

@@ -603,6 +603,26 @@ pub(crate) fn unicode_str_width(s: &str) -> usize {
     s.width()
 }
 
+pub fn get_skip_macro_names(attrs: &[ast::Attribute]) -> Vec<String> {
+    let mut skip_macro_names = vec![];
+    for attr in attrs {
+        // syntax::ast::Path is implemented partialEq
+        // but it is designed for segments.len() == 1
+        if format!("{}", attr.path) != "rustfmt::skip::macros" {
+            continue;
+        }
+
+        if let Some(list) = attr.meta_item_list() {
+            for spanned in list {
+                if let Some(name) = spanned.name() {
+                    skip_macro_names.push(name.to_string());
+                }
+            }
+        }
+    }
+    skip_macro_names
+}
+
 #[cfg(test)]
 mod test {
     use super::*;