From 29582b7ee16dfb9d79ad9effb78c5084348456aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Wawrzyniec=20Urba=C5=84czyk?=
 <mwu-tow@gazeta.pl>
Date: Thu, 2 Feb 2023 20:34:20 +0100
Subject: [PATCH] Fix for the cargo-installed build script usage. (#4096)

Use both current directory and current exe location for deducing the repository root location.
---
 build/build/src/repo.rs              | 26 ++++++++++++++----
 build/ci_utils/src/programs/cargo.rs | 41 ++++++++++++++++++++++++++--
 lib/rust/ensogl/pack/src/lib.rs      | 15 ++++++----
 3 files changed, 69 insertions(+), 13 deletions(-)

diff --git a/build/build/src/repo.rs b/build/build/src/repo.rs
index 0d1c84bb7b..6c9eb3aefc 100644
--- a/build/build/src/repo.rs
+++ b/build/build/src/repo.rs
@@ -28,15 +28,31 @@ pub fn looks_like_enso_repository_root(path: impl AsRef<Path>) -> bool {
     .unwrap_or(false)
 }
 
+/// Traverse the filesystem upwards, until we find a directory that looks like the root of the Enso.
+pub fn lookup_upwards_for_repository_root(mut path: &Path) -> Option<&Path> {
+    while !looks_like_enso_repository_root(path) {
+        path = path.parent()?;
+    }
+    Some(path)
+}
+
 /// Deduce the path to the root of the Enso repository.
 ///
 /// This function will traverse the filesystem upwards from the binary location until it finds a
 /// directory that looks like the root of the Enso repository.
 #[instrument(ret, err)]
 pub fn deduce_repository_path() -> Result<PathBuf> {
-    let mut path = ide_ci::env::current_exe()?;
-    while !looks_like_enso_repository_root(&path) {
-        ensure!(path.pop(), "Failed to deduce repository path.");
-    }
-    Ok(path)
+    // We check the current directory to support cases like using `cargo install` to reuse the
+    // build script binary.
+    let current_dir = ide_ci::env::current_dir()?;
+    let exe_path = ide_ci::env::current_exe()?;
+    let repo_root = lookup_upwards_for_repository_root(&current_dir)
+        .or_else(|| lookup_upwards_for_repository_root(&exe_path));
+    repo_root.map(PathBuf::from).with_context(|| {
+        format!(
+            "Failed to deduce repository path from current directory {} and executable path {}.",
+            current_dir.display(),
+            exe_path.display()
+        )
+    })
 }
diff --git a/build/ci_utils/src/programs/cargo.rs b/build/ci_utils/src/programs/cargo.rs
index 6c7f5e0593..584a9b13f7 100644
--- a/build/ci_utils/src/programs/cargo.rs
+++ b/build/ci_utils/src/programs/cargo.rs
@@ -39,6 +39,8 @@ impl Program for Cargo {
 #[derive(Clone, Copy, PartialEq, Eq, Debug, strum::AsRefStr)]
 #[strum(serialize_all = "kebab-case")]
 pub enum Command {
+    /// Run the benchmarks
+    Bench,
     /// Compile the current package
     Build,
     /// Analyze the current package and report errors, but don't build object files
@@ -55,8 +57,6 @@ pub enum Command {
     Run,
     /// Run the tests
     Test,
-    /// Run the benchmarks
-    Bench,
     /// Update dependencies listed in Cargo.lock
     Update,
     /// Search registry for crates
@@ -67,6 +67,8 @@ pub enum Command {
     Install,
     /// Uninstall a Rust binary
     Uninstall,
+    /// Print a JSON representation of a Cargo.toml file's location
+    LocateProject,
 }
 
 impl Manipulator for Command {
@@ -135,3 +137,38 @@ impl Manipulator for RunOption {
         }
     }
 }
+
+/// The representation in which to print the project location.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, strum::AsRefStr)]
+#[strum(serialize_all = "kebab-case")]
+pub enum MessageFormat {
+    /// JSON object with the path under the key "root".
+    Json,
+    /// Just the path.
+    Plain,
+}
+
+/// Options for the `cargo locate-project` command.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, strum::AsRefStr)]
+#[strum(serialize_all = "kebab-case")]
+pub enum LocateProjectOption {
+    /// Locate the Cargo.toml at the root of the workspace, as opposed to the current workspace
+    /// member.
+    Workspace,
+    /// The representation in which to print the project location.
+    MessageFormat(MessageFormat),
+}
+
+impl Manipulator for LocateProjectOption {
+    fn apply<C: IsCommandWrapper + ?Sized>(&self, command: &mut C) {
+        let base_arg = format!("--{}", self.as_ref());
+        command.arg(base_arg);
+        use LocateProjectOption::*;
+        match self {
+            Workspace => {}
+            MessageFormat(format) => {
+                command.arg(format.as_ref());
+            }
+        }
+    }
+}
diff --git a/lib/rust/ensogl/pack/src/lib.rs b/lib/rust/ensogl/pack/src/lib.rs
index ba6e4b9104..12cc3f157b 100644
--- a/lib/rust/ensogl/pack/src/lib.rs
+++ b/lib/rust/ensogl/pack/src/lib.rs
@@ -292,14 +292,17 @@ impl Paths {
 }
 
 pub async fn workspace_dir() -> Result<PathBuf> {
-    let output = Command::new(env!("CARGO"))
-        .arg("locate-project")
-        .arg("--workspace")
-        .arg("--message-format=plain")
+    use ide_ci::programs::cargo;
+    use ide_ci::programs::Cargo;
+    let output = Cargo
+        .cmd()?
+        .apply(&cargo::Command::LocateProject)
+        .apply(&cargo::LocateProjectOption::Workspace)
+        .apply(&cargo::LocateProjectOption::MessageFormat(cargo::MessageFormat::Plain))
         .output_ok()
         .await?
-        .stdout;
-    let cargo_path = Path::new(std::str::from_utf8(&output)?.trim());
+        .into_stdout_string()?;
+    let cargo_path = Path::new(output.trim());
     Ok(cargo_path.try_parent()?.to_owned())
 }