From d12026d12b07dcbfd8bd1914cdcd292888cec37f Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Sun, 4 Apr 2021 17:10:23 -0600
Subject: prevent circular inference chains

---
 src/makefile/mod.rs | 34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/src/makefile/mod.rs b/src/makefile/mod.rs
index 1f0b8a2..b887ad4 100644
--- a/src/makefile/mod.rs
+++ b/src/makefile/mod.rs
@@ -37,7 +37,6 @@ pub struct Makefile<'a> {
     pub first_non_special_target: Option<String>,
     args: &'a Args,
     // TODO borrow warnings from Python version
-    fucking_bullshit_recursion_stack: RefCell<Vec<String>>,
 }
 
 impl<'a> Makefile<'a> {
@@ -76,7 +75,6 @@ impl<'a> Makefile<'a> {
             targets: RefCell::new(targets),
             first_non_special_target,
             args,
-            fucking_bullshit_recursion_stack: RefCell::new(Vec::new()),
         }
     }
 
@@ -104,7 +102,16 @@ impl<'a> Makefile<'a> {
         }
     }
 
-    fn infer_target(&self, name: &str, banned_rules: Vec<&InferenceRule>) -> Result<()> {
+    fn infer_target(
+        &self,
+        name: &str,
+        banned_rules: Vec<&InferenceRule>,
+        banned_names: Vec<&str>,
+    ) -> Result<()> {
+        if banned_names.contains(&name) {
+            bail!("no infinite recursion allowed");
+        }
+        log::trace!("inferring {}, stack = {:?}", name, banned_names);
         let mut new_target = None;
 
         let follow_gnu = cfg!(feature = "full");
@@ -141,7 +148,7 @@ impl<'a> Makefile<'a> {
                 .prereqs(name)?
                 .inspect(|x| log::trace!("{:>58} prereq {}", name, x))
                 .map(|prereq_path_name| {
-                    if name == prereq_path_name {
+                    if name == prereq_path_name || banned_names.contains(&&*prereq_path_name) {
                         // we can't build this based on itself! fuck outta here
                         return None;
                     }
@@ -163,7 +170,9 @@ impl<'a> Makefile<'a> {
                         .or_else(|| {
                             let mut banned_rules = banned_rules.clone();
                             banned_rules.push(rule);
-                            self.infer_target(&prereq_path_name, banned_rules)
+                            let mut banned_names = banned_names.clone();
+                            banned_names.push(name);
+                            self.infer_target(&prereq_path_name, banned_rules, banned_names)
                                 .ok()
                                 .and_then(|_| {
                                     if self.targets.borrow().contains_key(&prereq_path_name) {
@@ -199,16 +208,6 @@ impl<'a> Makefile<'a> {
     }
 
     pub fn get_target(&self, name: &str) -> Result<Rc<RefCell<Target>>> {
-        if self
-            .fucking_bullshit_recursion_stack
-            .borrow()
-            .contains(&name.to_owned())
-        {
-            bail!("no infinite recursion allowed");
-        }
-        self.fucking_bullshit_recursion_stack
-            .borrow_mut()
-            .push(name.to_owned());
         // TODO implement .POSIX
         let follow_gnu = cfg!(feature = "full");
 
@@ -221,7 +220,7 @@ impl<'a> Makefile<'a> {
             false
         };
         if !self.targets.borrow().contains_key(name) || exists_but_infer_anyway {
-            self.infer_target(name, vec![])?;
+            self.infer_target(name, vec![], vec![])?;
         }
 
         let mut new_target = None;
@@ -258,8 +257,6 @@ impl<'a> Makefile<'a> {
                 .insert(new_target.name.clone(), Rc::new(RefCell::new(new_target)));
         }
 
-        self.fucking_bullshit_recursion_stack.borrow_mut().pop();
-
         let targets = self.targets.borrow();
         Ok(Rc::clone(
             targets
@@ -469,7 +466,6 @@ mod test {
             targets: Default::default(),
             first_non_special_target: None,
             args: &args,
-            fucking_bullshit_recursion_stack: Default::default(),
         };
 
         let target = file.get_target("this-is-a-test-case")?;
-- 
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