diff options
Diffstat (limited to 'pkgs/test/nixpkgs-check-by-name/src/nix_file.rs')
| -rw-r--r-- | pkgs/test/nixpkgs-check-by-name/src/nix_file.rs | 510 |
1 files changed, 510 insertions, 0 deletions
diff --git a/pkgs/test/nixpkgs-check-by-name/src/nix_file.rs b/pkgs/test/nixpkgs-check-by-name/src/nix_file.rs new file mode 100644 index 0000000000000..836c5e2dcdda5 --- /dev/null +++ b/pkgs/test/nixpkgs-check-by-name/src/nix_file.rs @@ -0,0 +1,510 @@ +//! This is a utility module for interacting with the syntax of Nix files + +use crate::utils::LineIndex; +use anyhow::Context; +use rnix::ast; +use rnix::ast::Expr; +use rnix::ast::HasEntry; +use rnix::SyntaxKind; +use rowan::ast::AstNode; +use rowan::TextSize; +use rowan::TokenAtOffset; +use std::collections::hash_map::Entry; +use std::collections::HashMap; +use std::fs::read_to_string; +use std::path::Path; +use std::path::PathBuf; + +/// A structure to store parse results of Nix files in memory, +/// making sure that the same file never has to be parsed twice +#[derive(Default)] +pub struct NixFileStore { + entries: HashMap<PathBuf, NixFile>, +} + +impl NixFileStore { + /// Get the store entry for a Nix file if it exists, otherwise parse the file, insert it into + /// the store, and return the value + /// + /// Note that this function only gives an anyhow::Result::Err for I/O errors. + /// A parse error is anyhow::Result::Ok(Result::Err(error)) + pub fn get(&mut self, path: &Path) -> anyhow::Result<&NixFile> { + match self.entries.entry(path.to_owned()) { + Entry::Occupied(entry) => Ok(entry.into_mut()), + Entry::Vacant(entry) => Ok(entry.insert(NixFile::new(path)?)), + } + } +} + +/// A structure for storing a successfully parsed Nix file +pub struct NixFile { + /// The parent directory of the Nix file, for more convenient error handling + pub parent_dir: PathBuf, + /// The path to the file itself, for errors + pub path: PathBuf, + pub syntax_root: rnix::Root, + pub line_index: LineIndex, +} + +impl NixFile { + /// Creates a new NixFile, failing for I/O or parse errors + fn new(path: impl AsRef<Path>) -> anyhow::Result<NixFile> { + let Some(parent_dir) = path.as_ref().parent() else { + anyhow::bail!("Could not get parent of path {}", path.as_ref().display()) + }; + + let contents = read_to_string(&path) + .with_context(|| format!("Could not read file {}", path.as_ref().display()))?; + let line_index = LineIndex::new(&contents); + + // NOTE: There's now another Nixpkgs CI check to make sure all changed Nix files parse + // correctly, though that uses mainline Nix instead of rnix, so it doesn't give the same + // errors. In the future we should unify these two checks, ideally moving the other CI + // check into this tool as well and checking for both mainline Nix and rnix. + rnix::Root::parse(&contents) + // rnix's ::ok returns Result<_, _> , so no error is thrown away like it would be with + // std::result's ::ok + .ok() + .map(|syntax_root| NixFile { + parent_dir: parent_dir.to_path_buf(), + path: path.as_ref().to_owned(), + syntax_root, + line_index, + }) + .with_context(|| format!("Could not parse file {} with rnix", path.as_ref().display())) + } +} + +/// Information about callPackage arguments +#[derive(Debug, PartialEq)] +pub struct CallPackageArgumentInfo { + /// The relative path of the first argument, or `None` if it's not a path. + pub relative_path: Option<PathBuf>, + /// Whether the second argument is an empty attribute set + pub empty_arg: bool, +} + +impl NixFile { + /// Returns information about callPackage arguments for an attribute at a specific line/column + /// index. + /// If the location is not of the form `<attr> = callPackage <arg1> <arg2>;`, `None` is + /// returned. + /// This function only returns `Err` for problems that can't be caused by the Nix contents, + /// but rather problems in this programs code itself. + /// + /// This is meant to be used with the location returned from `builtins.unsafeGetAttrPos`, e.g.: + /// - Create file `default.nix` with contents + /// ```nix + /// self: { + /// foo = self.callPackage ./default.nix { }; + /// } + /// ``` + /// - Evaluate + /// ```nix + /// builtins.unsafeGetAttrPos "foo" (import ./default.nix { }) + /// ``` + /// results in `{ file = ./default.nix; line = 2; column = 3; }` + /// - Get the NixFile for `.file` from a `NixFileStore` + /// - Call this function with `.line`, `.column` and `relative_to` as the (absolute) current directory + /// + /// You'll get back + /// ```rust + /// Some(CallPackageArgumentInfo { path = Some("default.nix"), empty_arg: true }) + /// ``` + /// + /// Note that this also returns the same for `pythonPackages.callPackage`. It doesn't make an + /// attempt at distinguishing this. + pub fn call_package_argument_info_at( + &self, + line: usize, + column: usize, + relative_to: &Path, + ) -> anyhow::Result<Option<CallPackageArgumentInfo>> { + let Some(attrpath_value) = self.attrpath_value_at(line, column)? else { + return Ok(None); + }; + self.attrpath_value_call_package_argument_info(attrpath_value, relative_to) + } + + // Internal function mainly to make it independently testable + fn attrpath_value_at( + &self, + line: usize, + column: usize, + ) -> anyhow::Result<Option<ast::AttrpathValue>> { + let index = self.line_index.fromlinecolumn(line, column); + + let token_at_offset = self + .syntax_root + .syntax() + .token_at_offset(TextSize::from(index as u32)); + + // The token_at_offset function takes indices to mean a location _between_ characters, + // which in this case is some spacing followed by the attribute name: + // + // foo = 10; + // /\ + // This is the token offset, we get both the (newline + indentation) on the left side, + // and the attribute name on the right side. + let TokenAtOffset::Between(_space, token) = token_at_offset else { + anyhow::bail!("Line {line} column {column} in {} is not the start of a token, but rather {token_at_offset:?}", self.path.display()) + }; + + // token looks like "foo" + let Some(node) = token.parent() else { + anyhow::bail!( + "Token on line {line} column {column} in {} does not have a parent node: {token:?}", + self.path.display() + ) + }; + + // node looks like "foo" + let Some(attrpath_node) = node.parent() else { + anyhow::bail!( + "Node in {} does not have a parent node: {node:?}", + self.path.display() + ) + }; + + if attrpath_node.kind() != SyntaxKind::NODE_ATTRPATH { + // This can happen for e.g. `inherit foo`, so definitely not a syntactic `callPackage` + return Ok(None); + } + // attrpath_node looks like "foo.bar" + let Some(attrpath_value_node) = attrpath_node.parent() else { + anyhow::bail!( + "Attribute path node in {} does not have a parent node: {attrpath_node:?}", + self.path.display() + ) + }; + + if !ast::AttrpathValue::can_cast(attrpath_value_node.kind()) { + anyhow::bail!( + "Node in {} is not an attribute path value node: {attrpath_value_node:?}", + self.path.display() + ) + } + // attrpath_value_node looks like "foo.bar = 10;" + + // unwrap is fine because we confirmed that we can cast with the above check. + // We could avoid this `unwrap` for a `clone`, since `cast` consumes the argument, + // but we still need it for the error message when the cast fails. + Ok(Some(ast::AttrpathValue::cast(attrpath_value_node).unwrap())) + } + + // Internal function mainly to make attrpath_value_at independently testable + fn attrpath_value_call_package_argument_info( + &self, + attrpath_value: ast::AttrpathValue, + relative_to: &Path, + ) -> anyhow::Result<Option<CallPackageArgumentInfo>> { + let Some(attrpath) = attrpath_value.attrpath() else { + anyhow::bail!("attrpath value node doesn't have an attrpath: {attrpath_value:?}") + }; + + // At this point we know it's something like `foo...bar = ...` + + if attrpath.attrs().count() > 1 { + // If the attribute path has multiple entries, the left-most entry is an attribute and + // can't be a `callPackage`. + // + // FIXME: `builtins.unsafeGetAttrPos` will return the same position for all attribute + // paths and we can't really know which one it is. We could have a case like + // `foo.bar = callPackage ... { }` and trying to determine if `bar` is a `callPackage`, + // where this is not correct. + // However, this case typically doesn't occur anyways, + // because top-level packages wouldn't be nested under an attribute set. + return Ok(None); + } + let Some(value) = attrpath_value.value() else { + anyhow::bail!("attrpath value node doesn't have a value: {attrpath_value:?}") + }; + + // At this point we know it's something like `foo = ...` + + let Expr::Apply(apply1) = value else { + // Not even a function call, instead something like `foo = null` + return Ok(None); + }; + let Some(function1) = apply1.lambda() else { + anyhow::bail!("apply node doesn't have a lambda: {apply1:?}") + }; + let Some(arg1) = apply1.argument() else { + anyhow::bail!("apply node doesn't have an argument: {apply1:?}") + }; + + // At this point we know it's something like `foo = <fun> <arg>`. + // For a callPackage, `<fun>` would be `callPackage ./file` and `<arg>` would be `{ }` + + let empty_arg = if let Expr::AttrSet(attrset) = arg1 { + // We can only statically determine whether the argument is empty if it's an attribute + // set _expression_, even though other kind of expressions could evaluate to an attribute + // set _value_. But this is what we want anyways + attrset.entries().next().is_none() + } else { + false + }; + + // Because callPackage takes two curried arguments, the first function needs to be a + // function call itself + let Expr::Apply(apply2) = function1 else { + // Not a callPackage, instead something like `foo = import ./foo` + return Ok(None); + }; + let Some(function2) = apply2.lambda() else { + anyhow::bail!("apply node doesn't have a lambda: {apply2:?}") + }; + let Some(arg2) = apply2.argument() else { + anyhow::bail!("apply node doesn't have an argument: {apply2:?}") + }; + + // At this point we know it's something like `foo = <fun2> <arg2> <arg1>`. + // For a callPackage, `<fun2>` would be `callPackage`, `<arg2>` would be `./file` + + // Check that <arg2> is a path expression + let path = if let Expr::Path(actual_path) = arg2 { + // Try to statically resolve the path and turn it into a nixpkgs-relative path + if let ResolvedPath::Within(p) = self.static_resolve_path(actual_path, relative_to) { + Some(p) + } else { + // We can't statically know an existing path inside Nixpkgs used as <arg2> + None + } + } else { + // <arg2> is not a path, but rather e.g. an inline expression + None + }; + + // Check that <fun2> is an identifier, or an attribute path with an identifier at the end + let ident = match function2 { + Expr::Ident(ident) => { + // This means it's something like `foo = callPackage <arg2> <arg1>` + ident + } + Expr::Select(select) => { + // This means it's something like `foo = self.callPackage <arg2> <arg1>`. + // We also end up here for e.g. `pythonPackages.callPackage`, but the + // callPackage-mocking method will take care of not triggering for this case. + + if select.default_expr().is_some() { + // Very odd case, but this would be `foo = self.callPackage or true ./test.nix {} + // (yes this is valid Nix code) + return Ok(None); + } + let Some(attrpath) = select.attrpath() else { + anyhow::bail!("select node doesn't have an attrpath: {select:?}") + }; + let Some(last) = attrpath.attrs().last() else { + // This case shouldn't be possible, it would be `foo = self. ./test.nix {}`, + // which shouldn't parse + anyhow::bail!("select node has an empty attrpath: {select:?}") + }; + if let ast::Attr::Ident(ident) = last { + ident + } else { + // Here it's something like `foo = self."callPackage" /test.nix {}` + // which we're not gonna bother with + return Ok(None); + } + } + // Any other expression we're not gonna treat as callPackage + _ => return Ok(None), + }; + + let Some(token) = ident.ident_token() else { + anyhow::bail!("ident node doesn't have a token: {ident:?}") + }; + + if token.text() == "callPackage" { + Ok(Some(CallPackageArgumentInfo { + relative_path: path, + empty_arg, + })) + } else { + Ok(None) + } + } +} + +/// The result of trying to statically resolve a Nix path expression +pub enum ResolvedPath { + /// Something like `./foo/${bar}/baz`, can't be known statically + Interpolated, + /// Something like `<nixpkgs>`, can't be known statically + SearchPath, + /// Path couldn't be resolved due to an IO error, + /// e.g. if the path doesn't exist or you don't have the right permissions + Unresolvable(std::io::Error), + /// The path is outside the given absolute path + Outside, + /// The path is within the given absolute path. + /// The `PathBuf` is the relative path under the given absolute path. + Within(PathBuf), +} + +impl NixFile { + /// Statically resolves a Nix path expression and checks that it's within an absolute path + /// + /// E.g. for the path expression `./bar.nix` in `./foo.nix` and an absolute path of the + /// current directory, the function returns `ResolvedPath::Within(./bar.nix)` + pub fn static_resolve_path(&self, node: ast::Path, relative_to: &Path) -> ResolvedPath { + if node.parts().count() != 1 { + // If there's more than 1 interpolated part, it's of the form `./foo/${bar}/baz`. + return ResolvedPath::Interpolated; + } + + let text = node.to_string(); + + if text.starts_with('<') { + // A search path like `<nixpkgs>`. There doesn't appear to be better way to detect + // these in rnix + return ResolvedPath::SearchPath; + } + + // Join the file's parent directory and the path expression, then resolve it + // FIXME: Expressions like `../../../../foo/bar/baz/qux` or absolute paths + // may resolve close to the original file, but may have left the relative_to. + // That should be checked more strictly + match self.parent_dir.join(Path::new(&text)).canonicalize() { + Err(resolution_error) => ResolvedPath::Unresolvable(resolution_error), + Ok(resolved) => { + // Check if it's within relative_to + match resolved.strip_prefix(relative_to) { + Err(_prefix_error) => ResolvedPath::Outside, + Ok(suffix) => ResolvedPath::Within(suffix.to_path_buf()), + } + } + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::tests; + use indoc::indoc; + + #[test] + fn detects_attributes() -> anyhow::Result<()> { + let temp_dir = tests::tempdir()?; + let file = temp_dir.path().join("file.nix"); + let contents = indoc! {r#" + toInherit: { + foo = 1; + "bar" = 2; + ${"baz"} = 3; + "${"qux"}" = 4; + + # A + quux + # B + = + # C + 5 + # D + ; + # E + + /**/quuux/**/=/**/5/**/;/*E*/ + + inherit toInherit; + } + "#}; + + std::fs::write(&file, contents)?; + + let nix_file = NixFile::new(&file)?; + + // These are builtins.unsafeGetAttrPos locations for the attributes + let cases = [ + (2, 3, Some("foo = 1;")), + (3, 3, Some(r#""bar" = 2;"#)), + (4, 3, Some(r#"${"baz"} = 3;"#)), + (5, 3, Some(r#""${"qux"}" = 4;"#)), + (8, 3, Some("quux\n # B\n =\n # C\n 5\n # D\n ;")), + (17, 7, Some("quuux/**/=/**/5/**/;")), + (19, 10, None), + ]; + + for (line, column, expected_result) in cases { + let actual_result = nix_file + .attrpath_value_at(line, column)? + .map(|node| node.to_string()); + assert_eq!(actual_result.as_deref(), expected_result); + } + + Ok(()) + } + + #[test] + fn detects_call_package() -> anyhow::Result<()> { + let temp_dir = tests::tempdir()?; + let file = temp_dir.path().join("file.nix"); + let contents = indoc! {r#" + self: with self; { + a.sub = null; + b = null; + c = import ./file.nix; + d = import ./file.nix { }; + e = pythonPackages.callPackage ./file.nix { }; + f = callPackage ./file.nix { }; + g = callPackage ({ }: { }) { }; + h = callPackage ./file.nix { x = 0; }; + i = callPackage ({ }: { }) (let in { }); + } + "#}; + + std::fs::write(&file, contents)?; + + let nix_file = NixFile::new(&file)?; + + let cases = [ + (2, None), + (3, None), + (4, None), + (5, None), + ( + 6, + Some(CallPackageArgumentInfo { + relative_path: Some(PathBuf::from("file.nix")), + empty_arg: true, + }), + ), + ( + 7, + Some(CallPackageArgumentInfo { + relative_path: Some(PathBuf::from("file.nix")), + empty_arg: true, + }), + ), + ( + 8, + Some(CallPackageArgumentInfo { + relative_path: None, + empty_arg: true, + }), + ), + ( + 9, + Some(CallPackageArgumentInfo { + relative_path: Some(PathBuf::from("file.nix")), + empty_arg: false, + }), + ), + ( + 10, + Some(CallPackageArgumentInfo { + relative_path: None, + empty_arg: false, + }), + ), + ]; + + for (line, expected_result) in cases { + let actual_result = nix_file.call_package_argument_info_at(line, 3, temp_dir.path())?; + assert_eq!(actual_result, expected_result); + } + + Ok(()) + } +} |