internal/frontend: change proxydatasource message

When pkgsite is using a non-DB datasource and tries to display a page
that requires the DB, it displays the error message "This page is not
supported by the proxy datasource."

There's nothing called the "proxy datasource" any more, and in any
case the message isn't really accurate: the point is that you need a
DB.

Change-Id: Id52d91a99f47056f3a2a3c240f2c7fe337c07599
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/348794
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/internal/frontend/404.go b/internal/frontend/404.go
index ecfbc59..3c57ce5 100644
--- a/internal/frontend/404.go
+++ b/internal/frontend/404.go
@@ -49,7 +49,7 @@
 
 	db, ok := ds.(*postgres.DB)
 	if !ok {
-		return proxydatasourceNotSupportedErr()
+		return datasourceNotSupportedErr()
 	}
 	ctx := r.Context()
 
diff --git a/internal/frontend/details.go b/internal/frontend/details.go
index 342e387..b01f6ee 100644
--- a/internal/frontend/details.go
+++ b/internal/frontend/details.go
@@ -99,12 +99,12 @@
 	}
 }
 
-func proxydatasourceNotSupportedErr() error {
+func datasourceNotSupportedErr() error {
 	return &serverError{
 		status: http.StatusFailedDependency,
 		epage: &errorPage{
 			messageTemplate: template.MakeTrustedTemplate(
-				`<h3 class="Error-message">This page is not supported by the proxydatasource.</h3>`),
+				`<h3 class="Error-message">This page is not supported by this datasource.</h3>`),
 		},
 	}
 }
diff --git a/internal/frontend/fetch.go b/internal/frontend/fetch.go
index e9732de..f329d86 100644
--- a/internal/frontend/fetch.go
+++ b/internal/frontend/fetch.go
@@ -94,7 +94,7 @@
 	defer derrors.Wrap(&err, "serveFetch(%q)", r.URL.Path)
 	if _, ok := ds.(*postgres.DB); !ok {
 		// There's no reason for the proxydatasource to need this codepath.
-		return proxydatasourceNotSupportedErr()
+		return datasourceNotSupportedErr()
 	}
 	if r.Method != http.MethodPost {
 		// If a user makes a GET request, treat this as a request for the
diff --git a/internal/frontend/imports.go b/internal/frontend/imports.go
index 7203adb..66503c7 100644
--- a/internal/frontend/imports.go
+++ b/internal/frontend/imports.go
@@ -98,7 +98,7 @@
 	db, ok := ds.(*postgres.DB)
 	if !ok {
 		// The proxydatasource does not support the imported by page.
-		return nil, proxydatasourceNotSupportedErr()
+		return nil, datasourceNotSupportedErr()
 	}
 
 	importedBy, err := db.GetImportedBy(ctx, pkgPath, modulePath, importedByLimit)
diff --git a/internal/frontend/search.go b/internal/frontend/search.go
index a1c12c4..dab2666 100644
--- a/internal/frontend/search.go
+++ b/internal/frontend/search.go
@@ -40,7 +40,7 @@
 	db, ok := ds.(*postgres.DB)
 	if !ok {
 		// The proxydatasource does not support the imported by page.
-		return proxydatasourceNotSupportedErr()
+		return datasourceNotSupportedErr()
 	}
 
 	ctx := r.Context()
diff --git a/internal/frontend/versions.go b/internal/frontend/versions.go
index a26abb5..e7f9c50 100644
--- a/internal/frontend/versions.go
+++ b/internal/frontend/versions.go
@@ -89,7 +89,7 @@
 	db, ok := ds.(*postgres.DB)
 	if !ok {
 		// The proxydatasource does not support the imported by page.
-		return nil, proxydatasourceNotSupportedErr()
+		return nil, datasourceNotSupportedErr()
 	}
 	versions, err := db.GetVersionsForPath(ctx, um.Path)
 	if err != nil {