internal/postgres: delete old versions from search_documents on insert

When inserting the latest version of a module, delete all versions
from search_documents before inserting the latest one. That will
remove from search all packages that are not in the latest version.

Change-Id: I58fe9a1e8974d7f3fbd1fa64212c4b0381895d09
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/337751
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>

internal/postgres/clean_test.go

@@ -29,10 +29,9 @@ func TestCleanBulk(t *testing.T) {
 	}
 	for _, mv := range append(want,
 		// These should not be cleaned.
-		"a.c@v1.0.0", // tagged
-		"b.c@v0.0.0-20170101000000-abcdef012345/p", // p is in search_documents (must be inserted first)
-		"b.c@v0.0.0-20190101000000-abcdef012345",   // latest version
-		"b.c@v0.0.0-20180101000000-abcdef012345",   // 'main' in version_map (see UpsertVersionMap below)
+		"a.c@v1.0.0",                             // tagged
+		"b.c@v0.0.0-20190101000000-abcdef012345", // latest version
+		"b.c@v0.0.0-20180101000000-abcdef012345", // 'main' in version_map (see UpsertVersionMap below)
 	) {
 		mod, ver, pkg := parseModuleVersionPackage(mv)
 		m := sample.Module(mod, ver, pkg)

internal/postgres/insert_module.go

@@ -149,6 +149,13 @@ func (db *DB) saveModule(ctx context.Context, m *internal.Module, lmv *internal.
 			return err
 		}
 
+		// Delete this module from search_documents completely. Below we'll
+		// insert the packages from this module. This will effectively remove
+		// packages from older module versions that are not in the latest one.
+		if err := deleteModuleFromSearchDocuments(ctx, tx, m.ModulePath, nil); err != nil {
+			return err
+		}
+
 		// If the most recent version of this module has an alternative module
 		// path, then do not insert its packages into search_documents (and
 		// delete whatever is there). This happens when a module that initially
@@ -176,7 +183,7 @@ func (db *DB) saveModule(ctx context.Context, m *internal.Module, lmv *internal.
 		}
 		if alt {
 			log.Infof(ctx, "%s@%s: not inserting into search documents", m.ModulePath, m.Version)
-			return deleteModuleFromSearchDocuments(ctx, tx, m.ModulePath, nil)
+			return nil
 		}
 		// Insert the module's packages into search_documents.
 		if err := upsertSearchDocuments(ctx, tx, m); err != nil {

internal/postgres/search_test.go

@@ -1300,7 +1300,6 @@ func TestDeleteFromSearch(t *testing.T) {
 	const modulePath = "deleteme.com"
 
 	initial := []searchDocumentRow{
-		// These must be from oldest to newest version, or older ones won't be inserted.
 		{modulePath + "/p1", modulePath, "v0.0.9"}, // oldest version of same module
 		{modulePath + "/p2", modulePath, "v1.1.0"}, // older version of same module
 		{modulePath + "/p4", modulePath, "v1.9.0"}, // newer version of same module
@@ -1313,7 +1312,8 @@ func TestDeleteFromSearch(t *testing.T) {
 			sm := sample.Module(r.ModulePath, r.Version, strings.TrimPrefix(r.PackagePath, r.ModulePath+"/"))
 			MustInsertModule(ctx, t, db, sm)
 		}
-		checkSearchDocuments(ctx, t, db, initial)
+		// Older versions are deleted by InsertModule, so only the newest versions are here.
+		checkSearchDocuments(ctx, t, db, initial[2:])
 	}
 
 	t.Run("DeleteOlderVersionFromSearchDocuments", func(t *testing.T) {