feat/2: add SPDX license header validation for source files

src/check/mod.rs

@@ -142,6 +142,7 @@ fn validate(paths: [&str; 3]) -> Result<report::Report, Box<dyn Error>> {
             results.add_items(validators::src_names_internal::validate(&parsed));
             results.add_items(validators::script_has_public_run_method::validate(&parsed));
             results.add_items(validators::constant_names::validate(&parsed));
+            results.add_items(validators::src_spdx_header::validate(&parsed));
         }
     }
     Ok(results)

src/check/validators/mod.rs

@@ -12,3 +12,6 @@ pub mod src_names_internal;
 
 /// Validates that test names are in the correct format.
 pub mod test_names;
+
+/// Validates that source files have SPDX license headers.
+pub mod src_spdx_header;

src/check/validators/src_spdx_header.rs

@@ -0,0 +1,147 @@
+use crate::check::{
+    utils::{FileKind, InvalidItem, IsFileKind, ValidatorKind},
+    Parsed,
+};
+use std::path::Path;
+
+/// Check if a file is a source file
+fn is_matching_file(file: &Path) -> bool {
+    file.is_file_kind(FileKind::Src)
+}
+
+#[must_use]
+/// Validates that source files have SPDX license headers.
+pub fn validate(parsed: &Parsed) -> Vec<InvalidItem> {
+    if !is_matching_file(&parsed.file) {
+        return Vec::new();
+    }
+
+    let mut invalid_items: Vec<InvalidItem> = Vec::new();
+
+    // Check if SPDX header is present
+    if find_spdx_header(&parsed.src).is_none() {
+        // Create a simple location for file-level issues
+        let loc = solang_parser::pt::Loc::File(0, 0, 0);
+        invalid_items.push(InvalidItem::new(
+            ValidatorKind::Src,
+            parsed,
+            loc,
+            "Missing SPDX-License-Identifier header".to_string(),
+        ));
+    }
+
+    invalid_items
+}
+
+/// Check if a line is a comment line
+fn is_comment_line(line: &str) -> bool {
+    line.starts_with("//") || line.starts_with("/*")
+}
+
+/// Check if a line contains a valid SPDX header
+fn has_spdx_header(line: &str) -> bool {
+    line.starts_with("// SPDX-License-Identifier:")
+}
+
+/// Find SPDX header in header section
+fn find_spdx_header(src: &str) -> Option<&str> {
+    for line in src.lines() {
+        let trimmed = line.trim();
+
+        // Skip empty lines
+        if trimmed.is_empty() {
+            continue;
+        }
+
+        // Check if this comment line has SPDX
+        if is_comment_line(trimmed) && has_spdx_header(trimmed) {
+            return Some(trimmed);
+        }
+
+        // If we hit any non-comment content, stop looking
+        if !is_comment_line(trimmed) {
+            break;
+        }
+    }
+
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::check::utils::ExpectedFindings;
+
+    #[test]
+    fn test_validate() {
+        let content = r"
+            // SPDX-License-Identifier: MIT
+            pragma solidity ^0.8.17;
+
+            contract Test {
+                uint256 public number;
+            }
+        ";
+
+        ExpectedFindings::new(0).assert_eq(content, &validate);
+    }
+
+    #[test]
+    fn test_validate_missing_spdx() {
+        let content = r"
+            pragma solidity ^0.8.17;
+
+            contract Test {
+                uint256 public number;
+            }
+        ";
+
+        let expected_findings = ExpectedFindings { src: 1, ..ExpectedFindings::default() };
+        expected_findings.assert_eq(content, &validate);
+    }
+
+    #[test]
+    fn test_validate_comment_then_spdx() {
+        let content = r"
+            // This is a comment
+            // SPDX-License-Identifier: MIT
+            pragma solidity ^0.8.17;
+
+            contract Test {
+                uint256 public number;
+            }
+        ";
+
+        ExpectedFindings::new(0).assert_eq(content, &validate);
+    }
+
+    #[test]
+    fn test_validate_pragma_then_spdx() {
+        let content = r"
+            pragma solidity ^0.8.17;
+            // SPDX-License-Identifier: MIT
+
+            contract Test {
+                uint256 public number;
+            }
+        ";
+
+        let expected_findings = ExpectedFindings { src: 1, ..ExpectedFindings::default() };
+        expected_findings.assert_eq(content, &validate);
+    }
+
+    #[test]
+    fn test_validate_comment_then_pragma() {
+        let content = r"
+            // This is a comment
+            pragma solidity ^0.8.17;
+
+            contract Test {
+                uint256 public number;
+            }
+        ";
+
+        let expected_findings = ExpectedFindings { src: 1, ..ExpectedFindings::default() };
+        expected_findings.assert_eq(content, &validate);
+    }
+}

tests/check-proj2-NoFindings/src/Counter.sol

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
 contract Counter {

tests/check-proj2-NoFindings/src/Library.sol

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
 library MyLibrary {

tests/check.rs

@@ -32,8 +32,13 @@ fn test_check_proj1_all_findings() {
         "Invalid constant or immutable name in ./src/Counter.sol on line 5: badImmutable",
         "Invalid constant or immutable name in ./src/Counter.sol on line 6: bad_constant",
         "Invalid constant or immutable name in ./test/Counter.t.sol on line 7: testVal",
+        "Invalid src method name in ./src/Counter.sol on line 1: Missing SPDX-License-Identifier header",
         "Invalid src method name in ./src/Counter.sol on line 23: internalShouldHaveLeadingUnderscore",
         "Invalid src method name in ./src/Counter.sol on line 25: privateShouldHaveLeadingUnderscore",
+        "Invalid src method name in ./src/CounterIgnored1.sol on line 1: Missing SPDX-License-Identifier header",
+        "Invalid src method name in ./src/CounterIgnored2.sol on line 1: Missing SPDX-License-Identifier header",
+        "Invalid src method name in ./src/CounterIgnored3.sol on line 1: Missing SPDX-License-Identifier header",
+        "Invalid src method name in ./src/CounterIgnored4.sol on line 1: Missing SPDX-License-Identifier header",
         "Invalid src method name in ./src/CounterIgnored4.sol on line 29: missingLeadingUnderscoreAndNotIgnored",
         "Invalid test name in ./test/Counter.t.sol on line 16: testIncrementBadName",
         "Invalid directive in ./src/Counter.sol: Invalid inline config item: this directive is invalid",