Suggest correct path in include_bytes!

compiler/rustc_builtin_macros/src/source_util.rs

@@ -12,10 +12,11 @@ use rustc_expand::module::DirOwnership;
 use rustc_parse::new_parser_from_file;
 use rustc_parse::parser::{ForceCollect, Parser};
 use rustc_session::lint::builtin::INCOMPLETE_INCLUDE;
+use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::Symbol;
 use rustc_span::{Pos, Span};
 use smallvec::SmallVec;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 
 // These macros all relate to the file system; they either return
@@ -185,7 +186,7 @@ pub fn expand_include_str(
         Ok(res) => res,
         Err(guar) => return DummyResult::any(sp, guar),
     };
-    match load_binary_file(cx, path.as_str(), sp, path_span) {
+    match load_binary_file(cx, path.as_str().as_ref(), sp, path_span) {
         Ok(bytes) => match std::str::from_utf8(&bytes) {
             Ok(src) => {
                 let interned_src = Symbol::intern(src);
@@ -210,7 +211,7 @@ pub fn expand_include_bytes(
         Ok(res) => res,
         Err(guar) => return DummyResult::any(sp, guar),
     };
-    match load_binary_file(cx, path.as_str(), sp, path_span) {
+    match load_binary_file(cx, path.as_str().as_ref(), sp, path_span) {
         Ok(bytes) => {
             let expr = cx.expr(sp, ast::ExprKind::IncludedBytes(bytes));
             MacEager::expr(expr)
@@ -221,7 +222,7 @@ pub fn expand_include_bytes(
 
 fn load_binary_file(
     cx: &mut ExtCtxt<'_>,
-    original_path: &str,
+    original_path: &Path,
     macro_span: Span,
     path_span: Span,
 ) -> Result<Lrc<[u8]>, Box<dyn MacResult>> {
@@ -239,24 +240,90 @@ fn load_binary_file(
                 macro_span,
                 format!("couldn't read {}: {io_err}", resolved_path.display()),
             );
-            if Path::new(original_path).is_relative() {
-                for prefix in ["..", "../.."] {
-                    let parent_path = Path::new(prefix).join(original_path);
-                    if resolve_path(&cx.sess, &parent_path, macro_span)
-                        .map_or(false, |p| p.exists())
-                    {
-                        err.span_suggestion(
-                            path_span,
-                            "it's in a parent directory",
-                            format!("\"{}\"", parent_path.display().to_string().escape_debug()),
-                            rustc_lint_defs::Applicability::MachineApplicable,
-                        );
-                        break;
-                    }
+
+            if original_path.is_relative() {
+                let source_map = cx.sess.source_map();
+                let new_path = source_map
+                    .span_to_filename(macro_span.source_callsite())
+                    .into_local_path()
+                    .and_then(|src| find_path_suggestion(source_map, src.parent()?, original_path))
+                    .and_then(|path| path.into_os_string().into_string().ok());
+
+                if let Some(new_path) = new_path {
+                    err.span_suggestion(
+                        path_span,
+                        "there is a file in another directory",
+                        format!("\"{}\"", new_path.escape_debug()),
+                        rustc_lint_defs::Applicability::MachineApplicable,
+                    );
                 }
             }
             let guar = err.emit();
             Err(DummyResult::any(macro_span, guar))
         }
     }
 }
+
+fn find_path_suggestion(
+    source_map: &SourceMap,
+    base_dir: &Path,
+    wanted_path: &Path,
+) -> Option<PathBuf> {
+    // Fix paths that assume they're relative to cargo manifest dir
+    let mut base_c = base_dir.components();
+    let mut wanted_c = wanted_path.components();
+    let mut without_base = None;
+    while let Some(wanted_next) = wanted_c.next() {
+        if wanted_c.as_path().file_name().is_none() {
+            break;
+        }
+        // base_dir may be absolute
+        while let Some(base_next) = base_c.next() {
+            if base_next == wanted_next {
+                without_base = Some(wanted_c.as_path());
+                break;
+            }
+        }
+    }
+    let root_absolute = without_base.into_iter().map(PathBuf::from);
+
+    let base_dir_components = base_dir.components().count();
+    // Avoid going all the way to the root dir
+    let max_parent_components = if base_dir.is_relative() {
+        base_dir_components + 1
+    } else {
+        base_dir_components.saturating_sub(1)
+    };
+
+    // Try with additional leading ../
+    let mut prefix = PathBuf::new();
+    let add = std::iter::from_fn(|| {
+        prefix.push("..");
+        Some(prefix.join(wanted_path))
+    })
+    .take(max_parent_components.min(3));
+
+    // Try without leading directories
+    let mut trimmed_path = wanted_path;
+    let remove = std::iter::from_fn(|| {
+        let mut components = trimmed_path.components();
+        let removed = components.next()?;
+        trimmed_path = components.as_path();
+        let _ = trimmed_path.file_name()?; // ensure there is a file name left
+        Some([
+            Some(trimmed_path.to_path_buf()),
+            (removed != std::path::Component::ParentDir)
+                .then(|| Path::new("..").join(trimmed_path)),
+        ])
+    })
+    .flatten()
+    .flatten()
+    .take(4);
+
+    for new_path in root_absolute.chain(add).chain(remove) {
+        if source_map.file_exists(&base_dir.join(&new_path)) {
+            return Some(new_path);
+        }
+    }
+    None
+}

tests/ui/include-macros/parent_dir.rs

@@ -1,4 +1,10 @@
 fn main() {
-    let _ = include_str!("include-macros/file.txt");    //~ ERROR coudln't read
-                                                        //~^HELP parent directory
+    let _ = include_str!("include-macros/file.txt");            //~ ERROR couldn't read
+                                                                //~^HELP another directory
+    let _ = include_str!("hello.rs");                           //~ ERROR couldn't read
+                                                                //~^HELP another directory
+    let _ = include_bytes!("../../data.bin");                   //~ ERROR couldn't read
+                                                                //~^HELP another directory
+    let _ = include_str!("tests/ui/include-macros/file.txt");   //~ ERROR couldn't read
+                                                                //~^HELP another directory
 }

tests/ui/include-macros/parent_dir.stderr

@@ -4,9 +4,39 @@ error: couldn't read $DIR/include-macros/file.txt: No such file or directory (os
 LL |     let _ = include_str!("include-macros/file.txt");
    |             ^^^^^^^^^^^^^-------------------------^
    |                          |
-   |                          help: it's in a parent directory: `"../include-macros/file.txt"`
+   |                          help: there is a file in another directory: `"file.txt"`
    |
    = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 1 previous error
+error: couldn't read $DIR/hello.rs: No such file or directory (os error 2)
+  --> $DIR/parent_dir.rs:4:13
+   |
+LL |     let _ = include_str!("hello.rs");
+   |             ^^^^^^^^^^^^^----------^
+   |                          |
+   |                          help: there is a file in another directory: `"../hello.rs"`
+   |
+   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: couldn't read $DIR/../../data.bin: No such file or directory (os error 2)
+  --> $DIR/parent_dir.rs:6:13
+   |
+LL |     let _ = include_bytes!("../../data.bin");
+   |             ^^^^^^^^^^^^^^^----------------^
+   |                            |
+   |                            help: there is a file in another directory: `"data.bin"`
+   |
+   = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: couldn't read $DIR/tests/ui/include-macros/file.txt: No such file or directory (os error 2)
+  --> $DIR/parent_dir.rs:8:13
+   |
+LL |     let _ = include_str!("tests/ui/include-macros/file.txt");
+   |             ^^^^^^^^^^^^^----------------------------------^
+   |                          |
+   |                          help: there is a file in another directory: `"file.txt"`
+   |
+   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 4 previous errors