Tweak parser

Author: charliermarsh

crates/ruff/src/checkers/ast/analyze/expression.rs

@@ -372,7 +372,6 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                             let location = expr.range();
                             match pyflakes::format::FormatSummary::try_from(val.as_ref()) {
                                 Err(e) => {
-                                    println!("error: {}", e);
                                     if checker.enabled(Rule::StringDotFormatInvalidFormat) {
                                         checker.diagnostics.push(Diagnostic::new(
                                             pyflakes::rules::StringDotFormatInvalidFormat {

crates/ruff/src/rules/pyflakes/format.rs

@@ -56,7 +56,6 @@ impl TryFrom<&str> for FormatSummary {
             };
 
             let nested = FormatString::from_str(format_spec)?;
-            println!("nested: {:?}", nested);
             for nested_part in nested.format_parts {
                 let FormatPart::Field { field_name, .. } = nested_part else {
                     continue;

crates/ruff_python_literal/src/format.rs

@@ -284,17 +284,20 @@ impl FormatSpec {
         let (width, text) = parse_number(text)?;
         let (grouping_option, text) = FormatGrouping::parse(text);
         let (precision, text) = parse_precision(text)?;
-        let (format_type, new_text) = FormatType::parse(text);
-        match format_type {
-            None if new_text != text => {
+        let (format_type, _text) = if text.is_empty() {
+            (None, text)
+        } else {
+            // If there's any remaining text, we should yield a valid format type and consume it
+            // all.
+            let (format_type, text) = FormatType::parse(text);
+            if format_type.is_none() {
                 return Err(FormatSpecError::InvalidFormatType);
             }
-            _ => (),
-        }
-
-        if !new_text.is_empty() {
-            return Err(FormatSpecError::InvalidFormatSpecifier);
-        }
+            if !text.is_empty() {
+                return Err(FormatSpecError::InvalidFormatSpecifier);
+            }
+            (format_type, text)
+        };
 
         if zero && fill.is_none() {
             fill.replace('0');