support for deletion (#450)

Even though for now everything is without validation

Author: Byron

git-refspec/src/parse.rs

@@ -36,10 +36,13 @@ pub(crate) mod function {
                 let src = (!src.is_empty()).then(|| src.as_bstr());
                 let dst = (!dst.is_empty()).then(|| dst.as_bstr());
                 match (src, dst) {
-                    (None, None) => {}
+                    (None, None) => (None, None), // match all
+                    (None, Some(dst)) => match operation {
+                        Operation::Push => (None, Some(dst)),
+                        Operation::Fetch => (Some("HEAD".into()), Some(dst)),
+                    },
                     _ => todo!("src or dst handling"),
-                };
-                (src, dst)
+                }
             }
             None => todo!("no colon"),
         };

git-refspec/src/spec.rs

@@ -1,5 +1,5 @@
 use crate::types::Push;
-use crate::{Instruction, Mode, Operation, RefSpec, RefSpecRef};
+use crate::{Fetch, Instruction, Mode, Operation, RefSpec, RefSpecRef};
 use bstr::BStr;
 
 /// Access
@@ -15,14 +15,29 @@ impl RefSpecRef<'_> {
             item.contains(&b'*')
         }
         match (self.op, self.mode, self.src, self.dst) {
+            (Operation::Fetch, Mode::Normal | Mode::Force, Some(src), Some(dst)) => {
+                Instruction::Fetch(Fetch::AndUpdateSingle {
+                    src,
+                    dst,
+                    allow_non_fast_forward: matches!(self.mode, Mode::Force),
+                })
+            }
             (Operation::Push, Mode::Normal | Mode::Force, Some(src), None) => Instruction::Push(Push::Single {
                 src,
                 dst: src,
                 allow_non_fast_forward: matches!(self.mode, Mode::Force),
             }),
+            (Operation::Push, Mode::Normal | Mode::Force, None, Some(dst)) => {
+                Instruction::Push(Push::Delete { ref_or_pattern: dst })
+            }
             (Operation::Push, Mode::Normal | Mode::Force, None, None) => Instruction::Push(Push::AllMatchingBranches {
                 allow_non_fast_forward: matches!(self.mode, Mode::Force),
             }),
+            (Operation::Fetch, Mode::Normal | Mode::Force, None, None) => {
+                Instruction::Fetch(Fetch::AllMatchingBranches {
+                    allow_non_fast_forward: matches!(self.mode, Mode::Force),
+                })
+            }
             (Operation::Push, Mode::Normal | Mode::Force, Some(src), Some(dst)) if has_pattern(src) => {
                 Instruction::Push(Push::MultipleWithGlob {
                     src,

git-refspec/src/types.rs

@@ -70,6 +70,11 @@ pub enum Push<'a> {
 
 #[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
 pub enum Fetch<'a> {
+    /// TODO: figure out what this actually does - it's valid for sure and only fetches HEAD -> FETCH_HEAD apparently
+    AllMatchingBranches {
+        /// Unclear what this does, but it's allowed
+        allow_non_fast_forward: bool,
+    },
     Only {
         /// The ref name to fetch on the remote side, without updating the local side.
         src: &'a BStr,

git-refspec/tests/fixtures/generated-archives/make_baseline.tar.xz

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:588dd4f20c618e60aff39c9cd47dd1300c83c39572f0c1db2c751ccbaca5709c
-size 9328
+oid sha256:515045d1eade39e1aeee1f171216ac389b8adc54af541b2ff49bf1b1ab68eae2
+size 9340

git-refspec/tests/fixtures/make_baseline.sh

@@ -84,6 +84,12 @@ baseline fetch 'HEAD:'
 baseline push ':refs/remotes/frotz/deleteme'
 baseline fetch ':refs/remotes/frotz/HEAD-to-me'
 
+baseline push ':a'
+baseline push '+:a'
+
+baseline fetch ':a'
+baseline fetch '+:a'
+
 baseline fetch 'refs/heads/*/for-linus:refs/remotes/mine/*-blah'
 baseline push 'refs/heads/*/for-linus:refs/remotes/mine/*-blah'
 

git-refspec/tests/parse/mod.rs

@@ -31,7 +31,10 @@ fn baseline() {
         match res {
             Ok(res) => match (res.is_ok(), err_code == 0) {
                 (true, true) | (false, false) => {}
-                _ => mismatch += 1,
+                _ => {
+                    eprintln!("{res:?} {err_code}");
+                    mismatch += 1;
+                }
             },
             Err(_) => {
                 panics += 1;
@@ -40,8 +43,11 @@ fn baseline() {
     }
     if panics != 0 || mismatch != 0 {
         panic!(
-            "Out of {} baseline entries, got {} mismatches and {} panics",
-            count, mismatch, panics
+            "Out of {} baseline entries, got {} right, ({} mismatches and {} panics)",
+            count,
+            count - (mismatch + panics),
+            mismatch,
+            panics
         );
     }
 }
@@ -68,11 +74,51 @@ mod invalid {
         }
     }
 
-    mod fetch {}
+    mod fetch {
+        use crate::parse::{assert_parse, b};
+        use git_refspec::{Fetch, Instruction};
+
+        #[test]
+        fn empty_lhs_colon_rhs_fetches_head_to_destination() {
+            assert_parse(
+                ":a",
+                Instruction::Fetch(Fetch::AndUpdateSingle {
+                    src: b("HEAD"),
+                    dst: b("a"),
+                    allow_non_fast_forward: false,
+                }),
+            );
+
+            assert_parse(
+                "+:a",
+                Instruction::Fetch(Fetch::AndUpdateSingle {
+                    src: b("HEAD"),
+                    dst: b("a"),
+                    allow_non_fast_forward: true,
+                }),
+            );
+        }
+
+        #[test]
+        fn colon_alone_is_for_fetching_into_fetchhead() {
+            assert_parse(
+                ":",
+                Instruction::Fetch(Fetch::AllMatchingBranches {
+                    allow_non_fast_forward: false,
+                }),
+            );
+            assert_parse(
+                "+:",
+                Instruction::Fetch(Fetch::AllMatchingBranches {
+                    allow_non_fast_forward: true,
+                }),
+            );
+        }
+    }
 
     mod push {
-        use crate::parse::assert_parse;
-        use git_refspec::{Instruction, Push};
+        use crate::parse::{assert_parse, b};
+        use git_refspec::{Instruction, Mode, Push};
 
         #[test]
         fn colon_alone_is_for_pushing_matching_refs() {
@@ -89,23 +135,35 @@ mod invalid {
                 }),
             );
         }
+
+        #[test]
+        fn delete() {
+            assert_parse(":a", Instruction::Push(Push::Delete { ref_or_pattern: b("a") }));
+            let spec = assert_parse("+:a", Instruction::Push(Push::Delete { ref_or_pattern: b("a") }));
+            assert_eq!(
+                spec.mode(),
+                Mode::Force,
+                "force is set, even though it has no effect in the actual instruction"
+            );
+        }
     }
 }
 
 mod util {
     use git_refspec::{Instruction, Operation, RefSpecRef};
 
-    // pub fn b(input: &str) -> &bstr::BStr {
-    //     input.into()
-    // }
+    pub fn b(input: &str) -> &bstr::BStr {
+        input.into()
+    }
 
     pub fn try_parse(spec: &str, op: Operation) -> Result<RefSpecRef<'_>, git_refspec::parse::Error> {
         git_refspec::parse(spec.into(), op)
     }
 
-    pub fn assert_parse(spec: &str, expected: Instruction<'_>) {
+    pub fn assert_parse<'a>(spec: &'a str, expected: Instruction<'_>) -> RefSpecRef<'a> {
         let spec = try_parse(spec, expected.operation()).expect("no error");
-        assert_eq!(spec.instruction(), expected)
+        assert_eq!(spec.instruction(), expected);
+        spec
     }
 }
 pub use util::*;