From b08b7b575fb8abf3848e2315d903f752b3f65924 Mon Sep 17 00:00:00 2001
From: Tom Clegg <tom@curii.com>
Date: Wed, 26 Jun 2024 17:37:53 -0400
Subject: [PATCH] 21701: Accept "manifest_text" and "current" replace_files
 sources.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>
---
 lib/controller/localdb/collection.go | 54 +++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 9 deletions(-)

diff --git a/lib/controller/localdb/collection.go b/lib/controller/localdb/collection.go
index bfc5c8a426..a661c30560 100644
--- a/lib/controller/localdb/collection.go
+++ b/lib/controller/localdb/collection.go
@@ -152,9 +152,8 @@ func (conn *Conn) lockUUID(ctx context.Context, uuid string) error {
 func (conn *Conn) applyReplaceFilesOption(ctx context.Context, fromUUID string, attrs map[string]interface{}, replaceFiles map[string]string) (map[string]interface{}, error) {
 	if len(replaceFiles) == 0 {
 		return attrs, nil
-	} else if mtxt, ok := attrs["manifest_text"].(string); ok && len(mtxt) > 0 {
-		return nil, httpserver.Errorf(http.StatusBadRequest, "ambiguous request: both 'replace_files' and attrs['manifest_text'] values provided")
 	}
+	providedManifestText, _ := attrs["manifest_text"].(string)
 
 	// Load the current collection (if any) and set up an
 	// in-memory filesystem.
@@ -216,6 +215,21 @@ func (conn *Conn) applyReplaceFilesOption(ctx context.Context, fromUUID string,
 		}
 	}
 
+	current := make(map[string]*arvados.Subtree)
+	// Check whether any sources are "current/...", and if so,
+	// populate current with the relevant snapshot.  Doing this
+	// ahead of time, before making any modifications to dstfs
+	// below, ensures that even instructions like {/a: current/b,
+	// b: current/a} will be handled correctly.
+	for _, src := range replaceFiles {
+		if strings.HasPrefix(src, "current/") && current[src] == nil {
+			current[src], err = arvados.Snapshot(dstfs, src[8:])
+			if err != nil {
+				return nil, fmt.Errorf("%s: %w", src, err)
+			}
+		}
+	}
+
 	var srcidloaded string
 	var srcfs arvados.FileSystem
 	// Apply the requested replacements.
@@ -234,15 +248,33 @@ func (conn *Conn) applyReplaceFilesOption(ctx context.Context, fromUUID string,
 			}
 			continue
 		}
+		var snap *arvados.Subtree
 		srcspec := strings.SplitN(src, "/", 2)
 		srcid, srcpath := srcspec[0], "/"
-		if !arvadosclient.PDHMatch(srcid) {
-			return nil, httpserver.Errorf(http.StatusBadRequest, "invalid source %q for replace_files[%q]: must be \"\" or \"PDH\" or \"PDH/path\"", src, dst)
-		}
 		if len(srcspec) == 2 && srcspec[1] != "" {
 			srcpath = srcspec[1]
 		}
-		if srcidloaded != srcid {
+		switch {
+		case srcid == "current":
+			snap = current[src]
+			if snap == nil {
+				return nil, fmt.Errorf("internal error: current[%s] == nil", src)
+			}
+		case srcid == "manifest_text":
+			if srcidloaded == srcid {
+				break
+			}
+			srcfs = nil
+			srccoll := &arvados.Collection{ManifestText: providedManifestText}
+			srcfs, err = srccoll.FileSystem(&arvados.StubClient{}, &arvados.StubClient{})
+			if err != nil {
+				return nil, err
+			}
+			srcidloaded = srcid
+		case arvadosclient.PDHMatch(srcid):
+			if srcidloaded == srcid {
+				break
+			}
 			srcfs = nil
 			srccoll, err := conn.CollectionGet(ctx, arvados.GetOptions{UUID: srcid})
 			if err != nil {
@@ -256,10 +288,14 @@ func (conn *Conn) applyReplaceFilesOption(ctx context.Context, fromUUID string,
 				return nil, err
 			}
 			srcidloaded = srcid
+		default:
+			return nil, httpserver.Errorf(http.StatusBadRequest, "invalid source %q for replace_files[%q]: must be \"\" or \"SRC\" or \"SRC/path\" where SRC is \"current\", \"manifest_text\", or a portable data hash", src, dst)
 		}
-		snap, err := arvados.Snapshot(srcfs, srcpath)
-		if err != nil {
-			return nil, httpserver.Errorf(http.StatusBadRequest, "error getting snapshot of %q from %q: %w", srcpath, srcid, err)
+		if snap == nil {
+			snap, err = arvados.Snapshot(srcfs, srcpath)
+			if err != nil {
+				return nil, httpserver.Errorf(http.StatusBadRequest, "error getting snapshot of %q from %q: %w", srcpath, srcid, err)
+			}
 		}
 		// Create intermediate dirs, in case dst is
 		// "newdir1/newdir2/dst".
-- 
2.39.5