fix(object): Report remaining input on error

Fixes #1099

Author: epage

gix-object/src/lib.rs

@@ -291,7 +291,12 @@ pub mod decode {
 
         impl std::fmt::Display for Error {
             fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                self.inner.fmt(f)
+                write!(f, "object parsing failed at `{}`", bstr::BStr::new(&self.remaining))?;
+                if self.inner.context().next().is_some() {
+                    writeln!(f)?;
+                    self.inner.fmt(f)?;
+                }
+                Ok(())
             }
         }
 

gix-object/tests/commit/mod.rs

@@ -169,7 +169,7 @@ fn invalid() {
     assert_eq!(
         CommitRef::from_bytes(partial_commit).unwrap_err().to_string(),
         if cfg!(feature = "verbose-object-parsing-errors") {
-            "expected `<timestamp>`, `<name> <<email>> <timestamp> <+|-><HHMM>`, `author <signature>`"
+            "object parsing failed at `1`\nexpected `<timestamp>`, `<name> <<email>> <timestamp> <+|-><HHMM>`, `author <signature>`"
         } else {
             "object parsing failed"
         }

gix-object/tests/tag/mod.rs

@@ -123,7 +123,7 @@ fn invalid() {
     assert_eq!(
         TagRef::from_bytes(partial_tag).unwrap_err().to_string(),
         if cfg!(feature = "verbose-object-parsing-errors") {
-            ""
+            "object parsing failed at `tagger Sebasti`"
         } else {
             "object parsing failed"
         }

gix-object/tests/tree/mod.rs

@@ -111,14 +111,12 @@ mod from_bytes {
     fn invalid() {
         let fixture = fixture_name("tree", "definitely-special.tree");
         let partial_tree = &fixture[..fixture.len() / 2];
-        assert_eq!(
-            TreeRef::from_bytes(partial_tree).unwrap_err().to_string(),
-            if cfg!(feature = "verbose-object-parsing-errors") {
-                ""
-            } else {
-                "object parsing failed"
-            }
-        );
+        let err = TreeRef::from_bytes(partial_tree).unwrap_err().to_string();
+        if cfg!(feature = "verbose-object-parsing-errors") {
+            assert!(err.starts_with("object parsing failed at `100644"), "{err}");
+        } else {
+            assert_eq!(err, "object parsing failed");
+        }
         assert_eq!(
             TreeRefIter::from_bytes(partial_tree).take_while(Result::is_ok).count(),
             9,