feat: rev opt in git dep + fix path opt in require

Lake/Config/Dependency.lean

@@ -17,7 +17,7 @@ In Lake, dependency sources currently come into flavors:
 -/
 inductive Source where
 | path (dir : FilePath)
-| git (url rev : String)
+| git (url : String) (rev : Option String)
 deriving Inhabited, Repr
 
 /-- A `Dependency` of a package. -/

Lake/Config/Resolve.lean

@@ -17,21 +17,26 @@ namespace Lake
 section
 open Git
 
-/-- Update the Git package in `dir` if necessary. -/
+/-- Update the Git package in `dir` to `rev` if not already at it. -/
 def updateGitPkg (name : String)
-(dir : FilePath) (rev : String) : (LogT IO) PUnit := do
-  if (← headRevision dir) == rev then return
-  logInfo s!"{name}: updating {dir} to revision {rev}"
-  unless ← revisionExists rev dir do fetch dir
-  checkoutDetach rev dir
+(dir : FilePath) (rev? : Option String) : LogT IO PUnit := do
+  if let some rev := rev? then
+    if (← headRevision dir) == rev then return
+    logInfo s!"{name}: updating {dir} to revision {rev}"
+    unless ← revisionExists rev dir do fetch dir
+    checkoutDetach rev dir
+  else
+    logInfo s!"{name}: updating {dir}"
+    pull dir
 
 /-- Clone the Git package as `dir`. -/
-def cloneGitPkg (name : String)
-(dir : FilePath) (url rev : String) : (LogT IO) PUnit := do
+def cloneGitPkg (name : String) (dir : FilePath)
+(url : String) (rev? : Option String) : LogT IO PUnit := do
   logInfo s!"{name}: cloning {url} to {dir}"
   clone url dir
-  let hash ← parseOriginRevision rev dir
-  checkoutDetach hash dir
+  if let some rev := rev? then
+    let hash ← parseOriginRevision rev dir
+    checkoutDetach hash dir
 
 abbrev ResolveM := StateT (NameMap PackageEntry) <| LogT IO
 
@@ -42,39 +47,37 @@ Attempts to reproduce the `PackageEntry` in the manifest (if one exists) unless
 `shouldUpdate` is true. Otherwise, produces the package based on `url` and `rev`
 and saves the result to the manifest.
 -/
-def materializeGitPkg (name : String)
-(dir : FilePath) (url rev : String) (shouldUpdate := true) : ResolveM PUnit := do
+def materializeGitPkg (name : String) (dir : FilePath)
+(url : String) (rev? : Option String) (shouldUpdate := true) : ResolveM PUnit := do
   if let some entry := (← get).find? name then
     if (← dir.isDir) then
       if url = entry.url then
         if shouldUpdate then
-          let rev ← parseOriginRevision rev dir
-          updateGitPkg name dir rev
+          updateGitPkg name dir rev?
+          let rev ← headRevision dir
           modify (·.insert name {entry with rev})
         else
           updateGitPkg name dir entry.rev
       else if shouldUpdate then
         logInfo s!"{name}: URL changed, deleting {dir} and cloning again"
         IO.FS.removeDirAll dir
-        cloneGitPkg name dir url rev
-        let rev ← parseOriginRevision rev dir
+        cloneGitPkg name dir url rev?
+        let rev ← headRevision dir
         modify (·.insert name {entry with url, rev})
     else
       if shouldUpdate then
-        cloneGitPkg name dir url rev
-        let rev ← parseOriginRevision rev dir
+        cloneGitPkg name dir url rev?
+        let rev ← headRevision dir
         modify (·.insert name {entry with url, rev})
       else
         cloneGitPkg name dir entry.url entry.rev
   else
     if (← dir.isDir) then
-      let rev ← parseOriginRevision rev dir
+      let rev ← headRevision dir
       modify (·.insert name {name, url, rev})
-      if (← headRevision dir) == rev then return
-      updateGitPkg name dir rev
     else
-      cloneGitPkg name dir url rev
-      let rev ← parseOriginRevision rev dir
+      cloneGitPkg name dir url rev?
+      let rev ← headRevision dir
       modify (·.insert name {name, url, rev})
 
 end
@@ -87,10 +90,10 @@ def materializeDep (ws : Workspace)
 (pkg : Package) (dep : Dependency) (shouldUpdate := true) : ResolveM FilePath :=
   match dep.src with
   | Source.path dir => return pkg.dir / dir
-  | Source.git url rev => do
+  | Source.git url rev? => do
     let name := dep.name.toString (escape := false)
     let depDir := ws.packagesDir / name
-    materializeGitPkg name depDir url rev shouldUpdate
+    materializeGitPkg name depDir url rev? shouldUpdate
     return depDir
 
 /--

Lake/DSL/Require.lean

@@ -14,7 +14,7 @@ syntax fromPath :=
   term
 
 syntax fromGit :=
-  &" git " term:max "@" term:max ("/" term)?
+  &" git " term:max ("@" term:max)? ("/" term)?
 
 syntax fromClause :=
   fromGit <|> fromPath
@@ -23,10 +23,16 @@ syntax depSpec :=
   ident " from " fromClause (" with " term)?
 
 def evalDepSpec : Syntax → TermElabM Dependency
-| `(depSpec| $name:ident from git $url @ $rev / $path $[with $args?:term]?) => do
+| `(depSpec| $name:ident from git $url $[@ $rev?]? $[/ $path?]? $[with $args?:term]?) => do
   let url ← evalTerm String url
-  let rev ← evalTerm String rev
-  let path ← evalTerm System.FilePath path
+  let rev ←
+    match rev? with
+    | some rev => some <$> evalTerm String rev
+    | none => pure none
+  let path ←
+    match path? with
+    | some path => evalTerm System.FilePath path
+    | none => pure "."
   let args ← match args? with
     | some args => evalTerm (List String) args
     | none => pure []
@@ -48,7 +54,8 @@ require bar from git "url.git"@"rev"/"optional"/"path-to"/"dir-with-pkg"
 ```
 
 Either form supports the optional `with` clause.
-The `/` and the following term in the git form of `require` is optional.
+The `@"rev"` and `/"path"/"dir"` parts of the git form of `require`
+are optional.
 
 The elements of both the `from` and `with` clauses are proper terms so
 normal computation is supported within them (though parentheses made be

Lake/Util/Git.lean

@@ -41,6 +41,9 @@ def quietInit (repo : Option FilePath := none) :=
 def fetch (repo : Option FilePath := none) :=
   execGit #["fetch"] repo
 
+def pull (repo : Option FilePath := none) :=
+  execGit #["pull"] repo
+
 def checkoutBranch (branch : String) (repo : Option FilePath := none) :=
   execGit #["checkout", "-B", branch] repo
 

README.md

@@ -195,7 +195,7 @@ require foo from "path"/"to"/"local"/"package" with ["optional","args"]
 require bar from git "url.git"@"rev"/"optional"/"path-to"/"dir-with-pkg"
 ```
 
-The first form adds a local dependency and the second form adds a Git dependency. For a Git dependency, the revision can be a commit hash, branch, or tag. Also, the `/` and the following term of the `require` is optional.
+The first form adds a local dependency and the second form adds a Git dependency. For a Git dependency, the revision can be a commit hash, branch, or tag. Also, the `@"rev"` and `/"path-to"/"term"` parts of the `require` are optional.
 
 Both forms also support an optional `with` clause to specify arguments to pass to the dependency's package configuration (i.e., same as `args` in a `lake build -- <args...>` invocation). The elements of both the `from` and `with` clauses are proper terms so normal computation is supported within them (though parentheses made be required to disambiguate the syntax).
 

examples/git/lakefile.lean

@@ -5,7 +5,7 @@ open System Lake DSL
 package git_hello
 
 require hello from
-  git "../.."@"master"/"examples"/"hello"
+  git "../.."/"examples"/"hello"
 
 @[defaultTarget]
 lean_exe git_hello {