From 7dbc884ac97a95d6aecb75e387dc39c5fd533735 Mon Sep 17 00:00:00 2001
From: Alan Zimmerman <alanzimm@meta.com>
Date: Thu, 22 Aug 2024 07:24:57 -0700
Subject: [PATCH] Disable eqwalizer for OTP < 26 (#48)

Summary:
Pull Request resolved: https://github.com/WhatsApp/erlang-language-platform/pull/48

OSS users want to use ELP with OTP < 26.
But eqwalizer does not support this.
So disable eqwalizer diagnostics in this case.

Differential Revision: D61660600
---
 crates/base_db/src/input.rs     |  3 +++
 crates/base_db/src/lib.rs       |  3 +++
 crates/ide_db/src/eqwalizer.rs  |  9 +++++++++
 crates/project_model/src/otp.rs | 22 ++++++++++++++++++++++
 4 files changed, 37 insertions(+)

diff --git a/crates/base_db/src/input.rs b/crates/base_db/src/input.rs
index dc703bef8..a67213fd0 100644
--- a/crates/base_db/src/input.rs
+++ b/crates/base_db/src/input.rs
@@ -12,6 +12,7 @@ use std::hash::Hash;
 use std::path::Path;
 use std::sync::Arc;
 
+use elp_project_model::otp::Otp;
 use elp_project_model::AppName;
 use elp_project_model::AppType;
 use elp_project_model::EqwalizerConfig;
@@ -194,6 +195,8 @@ impl AppStructure {
             db.set_project_data(project_id, Arc::new(project_data));
         }
         db.set_catch_all_source_root(self.catch_all_source_root);
+
+        db.set_otp_version(Otp::otp_version().ok());
     }
 }
 
diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
index 6dbdefece..ffa25b732 100644
--- a/crates/base_db/src/lib.rs
+++ b/crates/base_db/src/lib.rs
@@ -148,6 +148,9 @@ pub trait SourceDatabase: FileLoader + salsa::Database {
     #[salsa::input]
     fn project_data(&self, id: ProjectId) -> Arc<ProjectData>;
 
+    #[salsa::input]
+    fn otp_version(&self) -> Option<String>;
+
     /// A revision number that is bumped when the file state changes.
     /// Crucially, we update it in server mode when the unsaved file
     /// contents are changed in VFS, but also when we receive a
diff --git a/crates/ide_db/src/eqwalizer.rs b/crates/ide_db/src/eqwalizer.rs
index d20fe026f..37968408c 100644
--- a/crates/ide_db/src/eqwalizer.rs
+++ b/crates/ide_db/src/eqwalizer.rs
@@ -154,6 +154,9 @@ fn is_eqwalizer_enabled(
     file_id: FileId,
     include_generated: bool,
 ) -> bool {
+    if !otp_supported_by_eqwalizer(db) {
+        return false;
+    }
     if !include_generated && db.is_generated(file_id) {
         return false;
     }
@@ -178,6 +181,12 @@ fn is_eqwalizer_enabled(
     opt_in && !ignored
 }
 
+fn otp_supported_by_eqwalizer(db: &dyn EqwalizerDatabase) -> bool {
+    db.otp_version()
+        .and_then(|v| Some(v.as_str() > "25"))
+        .unwrap_or(true)
+}
+
 fn has_eqwalizer_app_marker(db: &dyn EqwalizerDatabase, source_root_id: SourceRootId) -> bool {
     if let Some(app_data) = db.app_data(source_root_id) {
         let source_root = db.source_root(source_root_id);
diff --git a/crates/project_model/src/otp.rs b/crates/project_model/src/otp.rs
index 3388a4428..ad1bb0b24 100644
--- a/crates/project_model/src/otp.rs
+++ b/crates/project_model/src/otp.rs
@@ -55,6 +55,28 @@ impl Otp {
         let result = fs::canonicalize(result)?;
         Ok(Utf8PathBuf::from_path_buf(result).expect("Could not create Utf8PathBuf"))
     }
+    pub fn otp_version() -> Result<String> {
+        let _timer = timeit!("otp_version");
+        let erl = ERL.read().unwrap();
+        let output = Command::new(&*erl)
+            .arg("-noshell")
+            .arg("-eval")
+            .arg("io:format('~s', [erlang:system_info(otp_release)])")
+            .arg("-s")
+            .arg("erlang")
+            .arg("halt")
+            .output()?;
+
+        if !output.status.success() {
+            bail!(
+                "Failed to get OTP version, error code: {:?}, stderr: {:?}",
+                output.status.code(),
+                String::from_utf8(output.stderr)
+            );
+        }
+        let val = String::from_utf8(output.stdout)?;
+        Ok(val)
+    }
 
     pub fn discover(path: Utf8PathBuf) -> (Otp, Vec<ProjectAppData>) {
         let apps = Self::discover_otp_apps(&path);