From 0c6f5e8376eb3c3ed2024637d2dd05fff8298638 Mon Sep 17 00:00:00 2001
From: 0xzhzh <178814591+0xzhzh@users.noreply.github.com>
Date: Sun, 3 Nov 2024 23:28:42 -0800
Subject: [PATCH] Use internal implementation of which()

---
 Cargo.lock      | 11 +++++++++
 Cargo.toml      |  3 ++-
 justfile        |  2 ++
 src/function.rs | 64 ++++++++++++++++++++++++++++++++++++++++++-------
 4 files changed, 70 insertions(+), 10 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 80a7276d..1ba1463b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -498,6 +498,15 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "is_executable"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4a1b5bad6f9072935961dfbf1cced2f3d129963d091b6f69f007fe04e758ae2"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.1"
@@ -535,8 +544,10 @@ dependencies = [
  "dirs",
  "dotenvy",
  "edit-distance",
+ "either",
  "executable-path",
  "heck",
+ "is_executable",
  "lexiclean",
  "libc",
  "num_cpus",
diff --git a/Cargo.toml b/Cargo.toml
index 8a516d99..bda81c5e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -30,7 +30,9 @@ derivative = "2.0.0"
 dirs = "5.0.1"
 dotenvy = "0.15"
 edit-distance = "2.0.0"
+either = "1.13.0"
 heck = "0.5.0"
+is_executable = "1.0.4"
 lexiclean = "0.0.1"
 libc = "0.2.0"
 num_cpus = "1.15.0"
@@ -51,7 +53,6 @@ tempfile = "3.0.0"
 typed-arena = "2.0.1"
 unicode-width = "0.2.0"
 uuid = { version = "1.0.0", features = ["v4"] }
-which = "6.0.0"
 
 [dev-dependencies]
 executable-path = "1.0.0"
diff --git a/justfile b/justfile
index d0ff455c..cf657782 100755
--- a/justfile
+++ b/justfile
@@ -6,6 +6,8 @@ alias t := test
 
 log := "warn"
 
+bingus := which("bash")
+
 export JUST_LOG := log
 
 [group: 'dev']
diff --git a/src/function.rs b/src/function.rs
index ff9c93b6..25c328b9 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -1,5 +1,6 @@
 use {
   super::*,
+  either::Either,
   heck::{
     ToKebabCase, ToLowerCamelCase, ToShoutyKebabCase, ToShoutySnakeCase, ToSnakeCase, ToTitleCase,
     ToUpperCamelCase,
@@ -110,7 +111,7 @@ pub(crate) fn get(name: &str) -> Option<Function> {
     "uppercase" => Unary(uppercase),
     "uuid" => Nullary(uuid),
     "without_extension" => Unary(without_extension),
-    "which" => Unary(which_exec),
+    "which" => Unary(which),
     _ => return None,
   };
   Some(function)
@@ -668,14 +669,59 @@ fn uuid(_context: Context) -> FunctionResult {
   Ok(uuid::Uuid::new_v4().to_string())
 }
 
-fn which_exec(_context: Context, s: &str) -> FunctionResult {
-  let path = which::which(s).unwrap_or_default();
-  path.to_str().map(str::to_string).ok_or_else(|| {
-    format!(
-      "unable to convert which executable path to string: {}",
-      path.display()
-    )
-  })
+fn which(context: Context, s: &str) -> FunctionResult {
+  use is_executable::IsExecutable;
+
+  let cmd = PathBuf::from(s);
+
+  let path_var;
+  let candidates = match cmd.components().count() {
+    0 => Err("empty command string".to_string())?,
+    1 => {
+      // cmd is a regular command
+      path_var = env::var_os("PATH").ok_or("Environment variable `PATH` is not set")?;
+      Either::Left(env::split_paths(&path_var).map(|path| path.join(cmd.clone())))
+    }
+    _ => {
+      // cmd contains a path separator, treat it as a path
+      Either::Right(iter::once(cmd))
+    }
+  };
+
+  for mut candidate in candidates.into_iter() {
+    if candidate.is_relative() {
+      // This candidate is a relative path, either because the user invoked `which("./rel/path")`,
+      // or because there was a relative path in `PATH`. Resolve it to an absolute path.
+      let cwd = context
+        .evaluator
+        .context
+        .search
+        .justfile
+        .parent()
+        .ok_or_else(|| {
+          format!(
+            "Could not resolve absolute path from `{}` relative to the justfile directory. Justfile `{}` had no parent.",
+            candidate.display(),
+            context.evaluator.context.search.justfile.display()
+          )
+        })?;
+      let mut cwd = PathBuf::from(cwd);
+      cwd.push(candidate);
+      candidate = cwd;
+    }
+
+    if candidate.is_executable() {
+      return candidate.to_str().map(str::to_string).ok_or_else(|| {
+        format!(
+          "Executable path is not valid unicode: {}",
+          candidate.display()
+        )
+      });
+    }
+  }
+
+  // No viable candidates; return an empty string
+  Ok(String::new())
 }
 
 fn without_extension(_context: Context, path: &str) -> FunctionResult {