refactor: download vendor dir on build if not available (#633)

automates download and build of `vendor/` files without loosing
reproducibility by comparing the commit SHA before running.

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: psteinroe

Cargo.lock

@@ -26,5 +26,8 @@ pgls_console.workspace    = true
 pgls_schema_cache         = { workspace = true, features = ["db"] }
 pgls_test_utils.workspace = true
 
+[build-dependencies]
+ureq = "2.9"
+
 [lib]
 doctest = false

crates/pgls_pglinter/Cargo.toml

@@ -0,0 +1,51 @@
+use std::fs;
+use std::io::Write;
+use std::path::Path;
+
+const EXPECTED_COMMIT: &str = "main";
+const REPO: &str = "pmpetit/pglinter";
+
+fn main() {
+    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    let vendor_dir = Path::new(&manifest_dir).join("vendor");
+    let sql_dir = vendor_dir.join("sql");
+    let sha_file = vendor_dir.join("COMMIT_SHA.txt");
+    let rules_file = sql_dir.join("rules.sql");
+
+    // Check if vendor files exist and SHA matches
+    let needs_download = if sha_file.exists() && rules_file.exists() {
+        let current_sha = fs::read_to_string(&sha_file).unwrap_or_default();
+        current_sha.trim() != EXPECTED_COMMIT
+    } else {
+        true
+    };
+
+    if needs_download {
+        println!("cargo:warning=Downloading pglinter vendor files...");
+
+        // Create directories
+        fs::create_dir_all(&sql_dir).expect("Failed to create vendor/sql directory");
+
+        // Download rules.sql using ureq (blocking HTTP client)
+        let url =
+            format!("https://raw.githubusercontent.com/{REPO}/{EXPECTED_COMMIT}/sql/rules.sql");
+
+        let response = ureq::get(&url)
+            .call()
+            .expect("Failed to download rules.sql");
+
+        let content = response.into_string().expect("Failed to read response");
+
+        let mut file = fs::File::create(&rules_file).expect("Failed to create rules.sql");
+        file.write_all(content.as_bytes())
+            .expect("Failed to write rules.sql");
+
+        // Write commit SHA
+        fs::write(&sha_file, EXPECTED_COMMIT).expect("Failed to write COMMIT_SHA.txt");
+
+        println!("cargo:warning=Downloaded pglinter vendor files successfully");
+    }
+
+    // Tell cargo to rerun if SHA changes
+    println!("cargo:rerun-if-changed=vendor/COMMIT_SHA.txt");
+}

crates/pgls_pglinter/build.rs

@@ -0,0 +1 @@
+main