If PKGX_PANTRY_DIR is set, don’t blow it away

.github/workflows/ci.yml

@@ -127,6 +127,22 @@ jobs:
             exit 1
           fi
 
+      # check that we update the pantry for unknown programs
+      # this works by deleting the entry for git then forcing
+      # pkgx to update the db, then trying to get git again
+      - run: |
+          set -x
+          rm -rf ~/.pkgx
+          rm -rf ~/.cache/pkgx/pantry/projects/git-scm.org
+          rm ~/.cache/pkgx/pantry.2.db
+          pkgx curl --version
+          test -f ~/.cache/pkgx/pantry.2.db
+          test ! -d ~/.cache/pkgx/pantry/projects/git-scm.org
+          pkgx git --version
+          test -d ~/.cache/pkgx/pantry/projects/git-scm.org
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        # ^^ only on one platform as wasteful otherwise
+
       - name: generate coverage
         run: |
           cargo install rustfilt

crates/cli/src/main.rs

@@ -60,7 +60,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
         if let Some(spinner) = &spinner {
             spinner.set_message("syncing pkg-db…");
         }
-        sync::replace(&config, &mut conn).await?;
+        sync::ensure(&config, &mut conn).await?;
         true
     } else {
         false
@@ -112,7 +112,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
                         spinner.set_message(msg);
                     }
                     // cmd not found ∴ sync in case it is new
-                    sync::replace(&config, &mut conn).await?;
+                    sync::update(&config, &mut conn).await?;
                     if let Some(spinner) = &spinner {
                         spinner.set_message("resolving pkg graph…");
                     }

crates/lib/src/sync.rs

@@ -19,7 +19,35 @@ pub fn should(config: &Config) -> Result<bool, Box<dyn Error>> {
     }
 }
 
-pub async fn replace(config: &Config, conn: &mut Connection) -> Result<(), Box<dyn Error>> {
+// doesn’t replace pantry clone, will build db
+// essential for working in a local pantry clone with PKGX_PANTRY_DIR set
+pub async fn ensure(config: &Config, conn: &mut Connection) -> Result<(), Box<dyn Error>> {
+    if !config.pantry_dir.join("projects").is_dir() {
+        replace(config, conn).await
+    } else {
+        let dest = &config.pantry_dir;
+        std::fs::create_dir_all(dest.clone())?;
+        let dir = OpenOptions::new()
+            .read(true) // Open in read-only mode; no need to write.
+            .open(dest)?;
+        dir.lock_exclusive()?;
+
+        pantry_db::cache(config, conn)?;
+
+        FileExt::unlock(&dir)?;
+
+        Ok(())
+    }
+}
+
+pub async fn update(config: &Config, conn: &mut Connection) -> Result<(), Box<dyn Error>> {
+    if std::env::var("PKGX_PANTRY_DIR").is_ok() {
+        return Err("PKGX_PANTRY_DIR is set, refusing to update pantry")?;
+    }
+    replace(config, conn).await
+}
+
+async fn replace(config: &Config, conn: &mut Connection) -> Result<(), Box<dyn Error>> {
     let url = env!("PKGX_PANTRY_TARBALL_URL");
     let dest = &config.pantry_dir;