From 57b423e3d75f596b10495a2eecfac7074953d948 Mon Sep 17 00:00:00 2001
From: Yuya Nishihara <yuya@tcha.org>
Date: Mon, 8 Apr 2024 16:52:27 +0900
Subject: [PATCH] fileset: relax identifier rule to accept more path-like
 strings

Since fileset is primarily used in CLI, it's better to avoid inner quoting if
possible. For example, ".." would have to be quoted in the original grammar
derived from the revset.

This patch also adds a stricter version of an identifier rule. If we add a
symbol alias, it will follow the "strict_identifier" rule.
---
 lib/src/fileset.pest      | 15 +++++++++++----
 lib/src/fileset.rs        |  3 +--
 lib/src/fileset_parser.rs | 17 +++++++++++++++--
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/lib/src/fileset.pest b/lib/src/fileset.pest
index 83e17780cc..c06a2ce73f 100644
--- a/lib/src/fileset.pest
+++ b/lib/src/fileset.pest
@@ -14,10 +14,17 @@
 
 whitespace = _{ " " | "\t" | "\r" | "\n" | "\x0c" }
 
-// TODO: adjust identifier rule for file names
-identifier_part = @{ (ASCII_ALPHANUMERIC | "_" | "/")+ }
+// XID_CONTINUE: https://www.unicode.org/reports/tr31/#Default_Identifier_Syntax
+// +, -, ., @, _: commonly used in file name including "." and ".."
+// /: path separator
+// \: path separator (Windows)
+// TODO: accept glob characters as identifier?
 identifier = @{
-  identifier_part ~ (("." | "-" | "+") ~ identifier_part)*
+  (XID_CONTINUE | "+" | "-" | "." | "@" | "_" | "/" | "\\")+
+}
+strict_identifier_part = @{ (ASCII_ALPHANUMERIC | "_")+ }
+strict_identifier = @{
+  strict_identifier_part ~ ("-" ~ strict_identifier_part)*
 }
 
 string_escape = @{ "\\" ~ ("t" | "r" | "n" | "0" | "\"" | "\\") }
@@ -42,7 +49,7 @@ function_arguments = {
 }
 
 // TODO: change rhs to string_literal to require quoting? #2101
-string_pattern = { identifier ~ pattern_kind_op ~ (identifier | string_literal) }
+string_pattern = { strict_identifier ~ pattern_kind_op ~ (identifier | string_literal) }
 
 primary = {
   "(" ~ whitespace* ~ expression ~ whitespace* ~ ")"
diff --git a/lib/src/fileset.rs b/lib/src/fileset.rs
index 1cbcab2f68..31368ae28d 100644
--- a/lib/src/fileset.rs
+++ b/lib/src/fileset.rs
@@ -396,8 +396,7 @@ mod tests {
             cwd: Path::new("/ws/cur"),
             workspace_root: Path::new("/ws"),
         };
-        // TODO: adjust identifier rule and test the expression parser instead
-        let parse = |input| FilePattern::parse(&ctx, input).map(FilesetExpression::pattern);
+        let parse = |text| parse(text, &ctx);
 
         // cwd-relative patterns
         assert_eq!(
diff --git a/lib/src/fileset_parser.rs b/lib/src/fileset_parser.rs
index 10a072cf05..ec41f4db80 100644
--- a/lib/src/fileset_parser.rs
+++ b/lib/src/fileset_parser.rs
@@ -40,8 +40,9 @@ impl Rule {
         match self {
             Rule::EOI => None,
             Rule::whitespace => None,
-            Rule::identifier_part => None,
             Rule::identifier => None,
+            Rule::strict_identifier_part => None,
+            Rule::strict_identifier => None,
             Rule::string_escape => None,
             Rule::string_content_char => None,
             Rule::string_content => None,
@@ -237,7 +238,7 @@ fn parse_primary_node(pair: Pair<Rule>) -> FilesetParseResult<ExpressionNode> {
         }
         Rule::string_pattern => {
             let (lhs, op, rhs) = first.into_inner().collect_tuple().unwrap();
-            assert_eq!(lhs.as_rule(), Rule::identifier);
+            assert_eq!(lhs.as_rule(), Rule::strict_identifier);
             assert_eq!(op.as_rule(), Rule::pattern_kind_op);
             let kind = lhs.as_str();
             let value = match rhs.as_rule() {
@@ -399,6 +400,18 @@ mod tests {
             parse_into_kind("dir/foo-bar_0.baz"),
             Ok(ExpressionKind::Identifier("dir/foo-bar_0.baz"))
         );
+        assert_eq!(
+            parse_into_kind("cli-reference@.md.snap"),
+            Ok(ExpressionKind::Identifier("cli-reference@.md.snap"))
+        );
+        assert_eq!(
+            parse_into_kind("柔術.jj"),
+            Ok(ExpressionKind::Identifier("柔術.jj"))
+        );
+        assert_eq!(
+            parse_into_kind(r#"Windows\Path"#),
+            Ok(ExpressionKind::Identifier(r#"Windows\Path"#))
+        );
     }
 
     #[test]