diff --git a/rust/hg-core/src/revlog/nodemap.rs b/rust/hg-core/src/revlog/nodemap.rs --- a/rust/hg-core/src/revlog/nodemap.rs +++ b/rust/hg-core/src/revlog/nodemap.rs @@ -13,7 +13,8 @@ //! is used in a more abstract context. use super::{ - Node, NodeError, NodePrefix, NodePrefixRef, Revision, RevlogIndex, + node::NULL_NODE, Node, NodeError, NodePrefix, NodePrefixRef, Revision, + RevlogIndex, NULL_REVISION, }; use std::fmt; @@ -250,6 +251,31 @@ }) } +/// validate that the candidate's node starts indeed with given prefix, +/// and treat ambiguities related to `NULL_REVISION`. +/// +/// From the data in the NodeTree, one can only conclude that some +/// revision is the only one for a *subprefix* of the one being looked up. +fn validate_candidate<'p>( + idx: &impl RevlogIndex, + prefix: NodePrefixRef<'p>, + rev: Option, +) -> Result, NodeMapError> { + if prefix.is_prefix_of(&NULL_NODE) { + // NULL_REVISION always matches a prefix made only of zeros + // and any other *valid* result is an ambiguity + match rev { + None => Ok(Some(NULL_REVISION)), + Some(r) => match has_prefix_or_none(idx, prefix, r)? { + None => Ok(Some(NULL_REVISION)), + _ => Err(NodeMapError::MultipleResults), + }, + } + } else { + rev.map_or(Ok(None), |r| has_prefix_or_none(idx, prefix, r)) + } +} + impl NodeTree { /// Initiate a NodeTree from an immutable slice-like of `Block` /// @@ -339,8 +365,6 @@ } /// Main working method for `NodeTree` searches - /// - /// This partial implementation lacks special cases for NULL_REVISION fn lookup<'p>( &self, prefix: NodePrefixRef<'p>, @@ -591,9 +615,7 @@ idx: &impl RevlogIndex, prefix: NodePrefixRef<'a>, ) -> Result, NodeMapError> { - self.lookup(prefix.clone()).and_then(|opt| { - opt.map_or(Ok(None), |rev| has_prefix_or_none(idx, prefix, rev)) - }) + validate_candidate(idx, prefix.clone(), self.lookup(prefix)?) } } @@ -723,8 +745,9 @@ assert_eq!(nt.find_hex(&idx, "0"), Err(MultipleResults)); assert_eq!(nt.find_hex(&idx, "01"), Ok(Some(9))); - assert_eq!(nt.find_hex(&idx, "00"), Ok(Some(0))); + assert_eq!(nt.find_hex(&idx, "00"), Err(MultipleResults)); assert_eq!(nt.find_hex(&idx, "00a"), Ok(Some(0))); + assert_eq!(nt.find_hex(&idx, "000"), Ok(Some(NULL_REVISION))); } #[test] @@ -743,7 +766,8 @@ }; assert_eq!(nt.find_hex(&idx, "10")?, Some(1)); assert_eq!(nt.find_hex(&idx, "c")?, Some(2)); - assert_eq!(nt.find_hex(&idx, "00")?, Some(0)); + assert_eq!(nt.find_hex(&idx, "00"), Err(MultipleResults)); + assert_eq!(nt.find_hex(&idx, "000")?, Some(NULL_REVISION)); assert_eq!(nt.find_hex(&idx, "01")?, Some(9)); Ok(()) }