Remove special-casing for editable requirements (#3869)

## Summary

There are a few behavior changes in here:

- We now enforce `--require-hashes` for editables, like pip. So if you
use `--require-hashes` with an editable requirement, we'll reject it. I
could change this if it seems off.
- We now treat source tree requirements, editable or not (e.g., both `-e
./black` and `./black`) as if `--refresh` is always enabled. This
doesn't mean that we _always_ rebuild them; but if you pass
`--reinstall`, then yes, we always rebuild them. I think this is an
improvement and is close to how editables work today.

Closes #3844.

Closes #2695.

crates/uv-distribution/src/distribution_database.rs

@@ -11,16 +11,16 @@ use tempfile::TempDir;
 use tokio::io::{AsyncRead, AsyncSeekExt, ReadBuf};
 use tokio::sync::Semaphore;
 use tokio_util::compat::FuturesAsyncReadCompatExt;
-use tracing::{info_span, instrument, warn, Instrument};
+use tracing::{debug, info_span, instrument, warn, Instrument};
 use url::Url;
 
 use distribution_filename::WheelFilename;
 use distribution_types::{
-    BuildableSource, BuiltDist, Dist, FileLocation, HashPolicy, Hashed, IndexLocations,
-    LocalEditable, Name, SourceDist,
+    BuildableSource, BuiltDist, Dist, FileLocation, HashPolicy, Hashed, IndexLocations, Name,
+    SourceDist,
 };
 use platform_tags::Tags;
-use pypi_types::{HashDigest, Metadata23};
+use pypi_types::HashDigest;
 use uv_cache::{ArchiveId, ArchiveTimestamp, CacheBucket, CacheEntry, Timestamp, WheelCache};
 use uv_client::{
     CacheControl, CachedClientError, Connectivity, DataWithCachePolicy, RegistryClient,
@@ -133,32 +133,6 @@ impl<'a, Context: BuildContext> DistributionDatabase<'a, Context> {
         }
     }
 
-    /// Build a directory into an editable wheel.
-    pub async fn build_wheel_editable(
-        &self,
-        editable: &LocalEditable,
-        editable_wheel_dir: &Path,
-    ) -> Result<(LocalWheel, Metadata23), Error> {
-        // Build the wheel.
-        let (dist, disk_filename, filename, metadata) = self
-            .builder
-            .build_editable(editable, editable_wheel_dir)
-            .await?;
-
-        // Unzip into the editable wheel directory.
-        let path = editable_wheel_dir.join(&disk_filename);
-        let target = editable_wheel_dir.join(cache_key::digest(&editable.path));
-        let id = self.unzip_wheel(&path, &target).await?;
-        let wheel = LocalWheel {
-            dist,
-            filename,
-            archive: self.build_context.cache().archive(&id),
-            hashes: vec![],
-        };
-
-        Ok((wheel, metadata))
-    }
-
     /// Fetch a wheel from the cache or download it from the index.
     ///
     /// While hashes will be generated in all cases, hash-checking is _not_ enforced and should
@@ -432,7 +406,11 @@ impl<'a, Context: BuildContext> DistributionDatabase<'a, Context> {
 
         // Optimization: Skip source dist download when we must not build them anyway.
         if no_build {
-            return Err(Error::NoBuild);
+            if source.is_editable() {
+                debug!("Allowing build for editable source distribution: {source}");
+            } else {
+                return Err(Error::NoBuild);
+            }
         }
 
         let lock = self.locks.acquire(source).await;
@@ -443,6 +421,7 @@ impl<'a, Context: BuildContext> DistributionDatabase<'a, Context> {
             .download_and_build_metadata(source, hashes, &self.client)
             .boxed_local()
             .await?;
+
         Ok(metadata)
     }