Auto merge of rust-lang#121833 - kornelski:parent_include, r=estebank

Suggest correct path in include_bytes!

`include_bytes!` paths are relative, and I'm often not sure how nested is the `.rs` file that I'm editing, so I have to guess the number of `"../.."`. This change searches `..` and `../..` for the given file and offers corrected path as a suggestion.

I wasn't sure how to get the right span, and how to properly escape it.

```text
error: couldn't read src/file.txt: No such file or directory (os error 2)
 --> src/main.rs:2:13
  |
2 |     let x = include_bytes!("file.txt");
  |             ^^^^^^^^^^^^^^^----------^
  |                            |
  |                            help: it's in a parent directory: `"../../file.txt"`
```

compiler/rustc_builtin_macros/src/source_util.rs

@@ -3,17 +3,22 @@ use rustc_ast::ptr::P;
 use rustc_ast::token;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast_pretty::pprust;
-use rustc_expand::base::{check_zero_tts, get_single_str_from_tts, parse_expr, resolve_path};
+use rustc_data_structures::sync::Lrc;
+use rustc_expand::base::{
+    check_zero_tts, get_single_str_from_tts, get_single_str_spanned_from_tts, parse_expr,
+    resolve_path,
+};
 use rustc_expand::base::{DummyResult, ExpandResult, ExtCtxt};
 use rustc_expand::base::{MacEager, MacResult, MacroExpanderResult};
 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, PathBuf};
 use std::rc::Rc;
 
 // These macros all relate to the file system; they either return
@@ -182,35 +187,26 @@ pub fn expand_include_str(
     tts: TokenStream,
 ) -> MacroExpanderResult<'static> {
     let sp = cx.with_def_site_ctxt(sp);
-    let ExpandResult::Ready(mac) = get_single_str_from_tts(cx, sp, tts, "include_str!") else {
+    let ExpandResult::Ready(mac) = get_single_str_spanned_from_tts(cx, sp, tts, "include_str!")
+    else {
         return ExpandResult::Retry(());
     };
-    let file = match mac {
-        Ok(file) => file,
+    let (path, path_span) = match mac {
+        Ok(res) => res,
         Err(guar) => return ExpandResult::Ready(DummyResult::any(sp, guar)),
     };
-    let file = match resolve_path(&cx.sess, file.as_str(), sp) {
-        Ok(f) => f,
-        Err(err) => {
-            let guar = err.emit();
-            return ExpandResult::Ready(DummyResult::any(sp, guar));
-        }
-    };
-    ExpandResult::Ready(match cx.source_map().load_binary_file(&file) {
+    ExpandResult::Ready(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);
                 MacEager::expr(cx.expr_str(sp, interned_src))
             }
             Err(_) => {
-                let guar = cx.dcx().span_err(sp, format!("{} wasn't a utf-8 file", file.display()));
+                let guar = cx.dcx().span_err(sp, format!("`{path}` wasn't a utf-8 file"));
                 DummyResult::any(sp, guar)
             }
         },
-        Err(e) => {
-            let guar = cx.dcx().span_err(sp, format!("couldn't read {}: {}", file.display(), e));
-            DummyResult::any(sp, guar)
-        }
+        Err(dummy) => dummy,
     })
 }
 
@@ -220,28 +216,127 @@ pub fn expand_include_bytes(
     tts: TokenStream,
 ) -> MacroExpanderResult<'static> {
     let sp = cx.with_def_site_ctxt(sp);
-    let ExpandResult::Ready(mac) = get_single_str_from_tts(cx, sp, tts, "include_bytes!") else {
+    let ExpandResult::Ready(mac) = get_single_str_spanned_from_tts(cx, sp, tts, "include_bytes!")
+    else {
         return ExpandResult::Retry(());
     };
-    let file = match mac {
-        Ok(file) => file,
+    let (path, path_span) = match mac {
+        Ok(res) => res,
         Err(guar) => return ExpandResult::Ready(DummyResult::any(sp, guar)),
     };
-    let file = match resolve_path(&cx.sess, file.as_str(), sp) {
-        Ok(f) => f,
+    ExpandResult::Ready(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)
+        }
+        Err(dummy) => dummy,
+    })
+}
+
+fn load_binary_file(
+    cx: &mut ExtCtxt<'_>,
+    original_path: &Path,
+    macro_span: Span,
+    path_span: Span,
+) -> Result<Lrc<[u8]>, Box<dyn MacResult>> {
+    let resolved_path = match resolve_path(&cx.sess, original_path, macro_span) {
+        Ok(path) => path,
         Err(err) => {
             let guar = err.emit();
-            return ExpandResult::Ready(DummyResult::any(sp, guar));
+            return Err(DummyResult::any(macro_span, guar));
         }
     };
-    ExpandResult::Ready(match cx.source_map().load_binary_file(&file) {
-        Ok(bytes) => {
-            let expr = cx.expr(sp, ast::ExprKind::IncludedBytes(bytes));
-            MacEager::expr(expr)
+    match cx.source_map().load_binary_file(&resolved_path) {
+        Ok(data) => Ok(data),
+        Err(io_err) => {
+            let mut err = cx.dcx().struct_span_err(
+                macro_span,
+                format!("couldn't read `{}`: {io_err}", resolved_path.display()),
+            );
+
+            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 with the same name in a different directory",
+                        format!("\"{}\"", new_path.escape_debug()),
+                        rustc_lint_defs::Applicability::MachineApplicable,
+                    );
+                }
+            }
+            let guar = err.emit();
+            Err(DummyResult::any(macro_span, guar))
         }
-        Err(e) => {
-            let guar = cx.dcx().span_err(sp, format!("couldn't read {}: {}", file.display(), e));
-            DummyResult::any(sp, 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
 }

compiler/rustc_expand/src/base.rs

@@ -1252,21 +1252,18 @@ pub fn resolve_path(sess: &Session, path: impl Into<PathBuf>, span: Span) -> PRe
     // after macro expansion (that is, they are unhygienic).
     if !path.is_absolute() {
         let callsite = span.source_callsite();
-        let mut result = match sess.source_map().span_to_filename(callsite) {
-            FileName::Real(name) => name
-                .into_local_path()
-                .expect("attempting to resolve a file path in an external file"),
-            FileName::DocTest(path, _) => path,
-            other => {
-                return Err(sess.dcx().create_err(errors::ResolveRelativePath {
-                    span,
-                    path: sess.source_map().filename_for_diagnostics(&other).to_string(),
-                }));
-            }
+        let source_map = sess.source_map();
+        let Some(mut base_path) = source_map.span_to_filename(callsite).into_local_path() else {
+            return Err(sess.dcx().create_err(errors::ResolveRelativePath {
+                span,
+                path: source_map
+                    .filename_for_diagnostics(&source_map.span_to_filename(callsite))
+                    .to_string(),
+            }));
         };
-        result.pop();
-        result.push(path);
-        Ok(result)
+        base_path.pop();
+        base_path.push(path);
+        Ok(base_path)
     } else {
         Ok(path)
     }
@@ -1379,6 +1376,15 @@ pub fn get_single_str_from_tts(
     tts: TokenStream,
     name: &str,
 ) -> ExpandResult<Result<Symbol, ErrorGuaranteed>, ()> {
+    get_single_str_spanned_from_tts(cx, span, tts, name).map(|res| res.map(|(s, _)| s))
+}
+
+pub fn get_single_str_spanned_from_tts(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    tts: TokenStream,
+    name: &str,
+) -> ExpandResult<Result<(Symbol, Span), ErrorGuaranteed>, ()> {
     let mut p = cx.new_parser_from_tts(tts);
     if p.token == token::Eof {
         let guar = cx.dcx().emit_err(errors::OnlyOneArgument { span, name });
@@ -1393,7 +1399,13 @@ pub fn get_single_str_from_tts(
     if p.token != token::Eof {
         cx.dcx().emit_err(errors::OnlyOneArgument { span, name });
     }
-    expr_to_string(cx, ret, "argument must be a string literal").map(|s| s.map(|(s, _)| s))
+    expr_to_spanned_string(cx, ret, "argument must be a string literal").map(|res| {
+        res.map_err(|err| match err {
+            Ok((err, _)) => err.emit(),
+            Err(guar) => guar,
+        })
+        .map(|(symbol, _style, span)| (symbol, span))
+    })
 }
 
 /// Extracts comma-separated expressions from `tts`.

compiler/rustc_span/src/lib.rs

@@ -427,6 +427,17 @@ impl FileName {
         src.hash(&mut hasher);
         FileName::InlineAsm(hasher.finish())
     }
+
+    /// Returns the path suitable for reading from the file system on the local host,
+    /// if this information exists.
+    /// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that.
+    pub fn into_local_path(self) -> Option<PathBuf> {
+        match self {
+            FileName::Real(path) => path.into_local_path(),
+            FileName::DocTest(path, _) => Some(path),
+            _ => None,
+        }
+    }
 }
 
 /// Represents a span.

tests/ui/include-macros/parent_dir.rs

@@ -0,0 +1,12 @@
+//@ normalize-stderr-test: "`: .*" -> "`: $$FILE_NOT_FOUND_MSG"
+
+fn main() {
+    let _ = include_str!("include-macros/file.txt");            //~ ERROR couldn't read
+                                                                //~^HELP different directory
+    let _ = include_str!("hello.rs");                           //~ ERROR couldn't read
+                                                                //~^HELP different directory
+    let _ = include_bytes!("../../data.bin");                   //~ ERROR couldn't read
+                                                                //~^HELP different directory
+    let _ = include_str!("tests/ui/include-macros/file.txt");   //~ ERROR couldn't read
+                                                                //~^HELP different directory
+}

tests/ui/include-macros/parent_dir.stderr

@@ -0,0 +1,50 @@
+error: couldn't read `$DIR/include-macros/file.txt`: $FILE_NOT_FOUND_MSG
+  --> $DIR/parent_dir.rs:4:13
+   |
+LL |     let _ = include_str!("include-macros/file.txt");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: there is a file with the same name in a different directory
+   |
+LL |     let _ = include_str!("file.txt");
+   |                          ~~~~~~~~~~
+
+error: couldn't read `$DIR/hello.rs`: $FILE_NOT_FOUND_MSG
+  --> $DIR/parent_dir.rs:6:13
+   |
+LL |     let _ = include_str!("hello.rs");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: there is a file with the same name in a different directory
+   |
+LL |     let _ = include_str!("../hello.rs");
+   |                          ~~~~~~~~~~~~~
+
+error: couldn't read `$DIR/../../data.bin`: $FILE_NOT_FOUND_MSG
+  --> $DIR/parent_dir.rs:8:13
+   |
+LL |     let _ = include_bytes!("../../data.bin");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: there is a file with the same name in a different directory
+   |
+LL |     let _ = include_bytes!("data.bin");
+   |                            ~~~~~~~~~~
+
+error: couldn't read `$DIR/tests/ui/include-macros/file.txt`: $FILE_NOT_FOUND_MSG
+  --> $DIR/parent_dir.rs:10:13
+   |
+LL |     let _ = include_str!("tests/ui/include-macros/file.txt");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `include_str` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: there is a file with the same name in a different directory
+   |
+LL |     let _ = include_str!("file.txt");
+   |                          ~~~~~~~~~~
+
+error: aborting due to 4 previous errors
+

tests/ui/macros/macros-nonfatal-errors.rs

@@ -1,4 +1,4 @@
-//@ normalize-stderr-test: "existed:.*\(" -> "existed: $$FILE_NOT_FOUND_MSG ("
+//@ normalize-stderr-test: "`: .*" -> "`: $$FILE_NOT_FOUND_MSG"
 
 // test that errors in a (selection) of macros don't kill compilation
 // immediately, so that we get more errors listed at a time.

tests/ui/macros/macros-nonfatal-errors.stderr

@@ -200,7 +200,7 @@ error: argument must be a string literal
 LL |     include_str!(invalid);
    |                  ^^^^^^^
 
-error: couldn't read $DIR/i'd be quite surprised if a file with this name existed: $FILE_NOT_FOUND_MSG (os error 2)
+error: couldn't read `$DIR/i'd be quite surprised if a file with this name existed`: $FILE_NOT_FOUND_MSG
   --> $DIR/macros-nonfatal-errors.rs:113:5
    |
 LL |     include_str!("i'd be quite surprised if a file with this name existed");
@@ -214,7 +214,7 @@ error: argument must be a string literal
 LL |     include_bytes!(invalid);
    |                    ^^^^^^^
 
-error: couldn't read $DIR/i'd be quite surprised if a file with this name existed: $FILE_NOT_FOUND_MSG (os error 2)
+error: couldn't read `$DIR/i'd be quite surprised if a file with this name existed`: $FILE_NOT_FOUND_MSG
   --> $DIR/macros-nonfatal-errors.rs:115:5
    |
 LL |     include_bytes!("i'd be quite surprised if a file with this name existed");