Suggest correct path in include_bytes!

Author: kornelski

compiler/rustc_builtin_macros/src/source_util.rs

@@ -3,18 +3,20 @@ use rustc_ast::ptr::P;
 use rustc_ast::token;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast_pretty::pprust;
+use rustc_data_structures::sync::Lrc;
 use rustc_expand::base::{
-    check_zero_tts, get_single_str_from_tts, parse_expr, resolve_path, DummyResult, ExtCtxt,
-    MacEager, MacResult,
+    check_zero_tts, get_single_str_from_tts, get_single_str_spanned_from_tts, parse_expr,
+    resolve_path, DummyResult, ExtCtxt, MacEager, MacResult,
 };
 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
@@ -180,32 +182,22 @@ pub fn expand_include_str(
     tts: TokenStream,
 ) -> Box<dyn MacResult + 'static> {
     let sp = cx.with_def_site_ctxt(sp);
-    let file = match get_single_str_from_tts(cx, sp, tts, "include_str!") {
-        Ok(file) => file,
+    let (path, path_span) = match get_single_str_spanned_from_tts(cx, sp, tts, "include_str!") {
+        Ok(res) => res,
         Err(guar) => return 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 DummyResult::any(sp, guar);
-        }
-    };
-    match cx.source_map().load_binary_file(&file) {
+    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,
     }
 }
 
@@ -215,25 +207,123 @@ pub fn expand_include_bytes(
     tts: TokenStream,
 ) -> Box<dyn MacResult + 'static> {
     let sp = cx.with_def_site_ctxt(sp);
-    let file = match get_single_str_from_tts(cx, sp, tts, "include_bytes!") {
-        Ok(file) => file,
+    let (path, path_span) = match get_single_str_spanned_from_tts(cx, sp, tts, "include_bytes!") {
+        Ok(res) => res,
         Err(guar) => return DummyResult::any(sp, guar),
     };
-    let file = match resolve_path(&cx.sess, file.as_str(), sp) {
-        Ok(f) => f,
+    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 DummyResult::any(sp, guar);
+            return Err(DummyResult::any(macro_span, guar));
         }
     };
-    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

@@ -1331,6 +1331,15 @@ pub fn get_single_str_from_tts(
     tts: TokenStream,
     name: &str,
 ) -> Result<Symbol, ErrorGuaranteed> {
+    get_single_str_spanned_from_tts(cx, span, tts, name).map(|(s, _)| s)
+}
+
+pub fn get_single_str_spanned_from_tts(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    tts: TokenStream,
+    name: &str,
+) -> 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 });
@@ -1342,7 +1351,12 @@ 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)
+    expr_to_spanned_string(cx, ret, "argument must be a string literal")
+        .map_err(|err| match err {
+            Ok((err, _)) => err.emit(),
+            Err(guar) => guar,
+        })
+        .map(|(symbol, _style, span)| (symbol, span))
 }
 
 /// Extracts comma-separated expressions from `tts`.

tests/ui/include-macros/parent_dir.rs

@@ -0,0 +1,10 @@
+fn main() {
+    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

@@ -0,0 +1,42 @@
+error: couldn't read $DIR/include-macros/file.txt: No such file or directory (os error 2)
+  --> $DIR/parent_dir.rs:2:13
+   |
+LL |     let _ = include_str!("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: 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
+