populate: fail if find fails looking for .rsync-filter files

Looking for .rsync-filter files that apply to a file source, a failing
find counted as finding none, and only happened with rsync 3.5.0 and
later.  Like in the shell implementation, find runs before each
transfer with filter files, and its failure stops populate with find's
message, e.g. for a source that's missing, or contains a directory find
can't read, which would also have switched off the check of
insecureLinks.  A signal during find takes effect right after it.

1 files changed, 11 insertions, 10 deletions

diff --git a/pkgs/populate/src/rsync.rs b/pkgs/populate/src/rsync.rs
index 78022ab..0ab92e6 100644
--- a/pkgs/populate/src/rsync.rs
+++ b/pkgs/populate/src/rsync.rs
@@ -150,7 +150,10 @@ fn insecure_links(context: &Context, config: &Config, source: &str) -> Result<bo
         .and_then(|line| line.split_whitespace().nth(2))
         .unwrap_or("")
         .to_string();
-    if !version_at_least(&version, "3.5.0") || !filtered(source) {
+    // Also with older versions of rsync, so a source that's missing, or
+    // that contains a directory find can't read, fails before rsync runs.
+    let filtered = filtered(source)?;
+    if !version_at_least(&version, "3.5.0") || !filtered {
         return Ok(false);
     }
     // A dry run of the same transfer, as far as filtering goes.
@@ -215,26 +218,24 @@ fn insecure_links(context: &Context, config: &Config, source: &str) -> Result<bo
 }
 
 /// Whether a .rsync-filter file applies to source: one therein, or in a
-/// directory above it.
-fn filtered(source: &str) -> bool {
+/// directory above it.  Fails, with find's message, if find fails.
+fn filtered(source: &str) -> Result<bool> {
     let found = run::output(Command::new("find").arg(source).args([
         "-name",
         ".rsync-filter",
         "-print",
         "-quit",
-    ]))
-    .map(|out| !out.is_empty())
-    .unwrap_or(false);
-    if found {
-        return true;
+    ]))?;
+    if !found.is_empty() {
+        return Ok(true);
     }
     let mut above = parent(source);
     loop {
         if Path::new(&above).join(".rsync-filter").exists() {
-            return true;
+            return Ok(true);
         }
         if above == "/" || above == "." {
-            return false;
+            return Ok(false);
         }
         above = parent(&above);
     }