Merge pull request #1113 from pkgxdev/no-overwrite

Don’t wait for lock to free & then reinstall lol

Author: mxcl

.github/workflows/ci.yml

@@ -74,7 +74,7 @@ jobs:
         with:
           path-to-lcov: coverage/lcov.info
           parallel: true
-          flag-name: ${{ matrix.os }}
+          flag-name: ${{ matrix.os }}-unit
 
   coverage-integration:
     needs: fmt
@@ -91,6 +91,10 @@ jobs:
           RUSTFLAGS="-C instrument-coverage" cargo build
           echo "$PWD/target/debug" >> $GITHUB_PATH
 
+      # testing for installing multiple of the same thing at once is ok
+      - run: pkgx +gnome.org/libxml2 & pkgx +gnome.org/libxml2 & pkgx +gnome.org/libxml2
+      # ^^ KEEP FIRST, IT MUST INSTALL
+
       - run: pkgx --help
       - run: pkgx --version
       - run: pkgx +git
@@ -114,6 +118,15 @@ jobs:
       # testing we correctly handle +pkg syntax for pkgs with no env
       - run: pkgx +curl.se/ca-certs
 
+      # create a fork bomb, but since it’s via pkgx we prevent it
+      - run: |
+          echo '#!/bin/sh' > foo
+          echo 'pkgx -- /bin/sh "$0"' >> foo
+          chmod u+x foo
+          if ./foo; then
+            exit 1
+          fi
+
       - name: generate coverage
         run: |
           cargo install rustfilt
@@ -130,10 +143,10 @@ jobs:
         with:
           path-to-lcov: lcov.info
           parallel: true
-          flag-name: ${{ matrix.os }}
+          flag-name: ${{ matrix.os }}-integration
 
   upload-coverage:
-    needs: [coverage-unit, coverage-integration, test]
+    needs: [coverage-unit, coverage-integration]
     runs-on: ubuntu-latest
     steps:
       - uses: coverallsapp/github-action@v2

crates/lib/src/install.rs

@@ -39,18 +39,30 @@ where
     fs::create_dir_all(&shelf)?;
     let shelf = OpenOptions::new()
         .read(true) // Open the directory in read-only mode
-        .open(shelf)?;
+        .open(shelf.clone())?;
 
     task::spawn_blocking({
         let shelf = shelf.try_clone()?;
         move || {
             shelf
                 .lock_exclusive()
-                .expect("couldn’t obtain lock, is another pkgx instance running?");
+                .expect("unexpected error: install locking failed");
         }
     })
     .await?;
 
+    let dst_path = cellar::dst(pkg, config);
+
+    // did another instance of pkx install us while we waited for the lock?
+    // if so, we’re good: eject
+    if fs::exists(dst_path.clone())? {
+        FileExt::unlock(&shelf)?;
+        return Ok(Installation {
+            path: dst_path,
+            pkg: pkg.clone(),
+        });
+    }
+
     let url = inventory::get_url(pkg, config);
     let client = Client::new();
     let rsp = client.get(url).send().await?.error_for_status()?;
@@ -86,7 +98,7 @@ where
     archive.unpack(&config.pkgx_dir).await?;
 
     let installation = Installation {
-        path: cellar::dst(pkg, config),
+        path: dst_path,
         pkg: pkg.clone(),
     };