allow specifying projects in a workspace more than one level under it (#59849)

(cherry picked from commit b26e7cc)

Author: KristofferC

base/loading.jl

@@ -667,20 +667,45 @@ function env_project_file(env::String)::Union{Bool,String}
 end
 
 function base_project(project_file)
-    base_dir = abspath(joinpath(dirname(project_file), ".."))
-    base_project_file = env_project_file(base_dir)
-    base_project_file isa String || return nothing
-    d = parsed_toml(base_project_file)
-    workspace = get(d, "workspace", nothing)::Union{Dict{String, Any}, Nothing}
-    if workspace === nothing
-        return nothing
-    end
-    projects = get(workspace, "projects", nothing)::Union{Vector{String}, Nothing, String}
-    projects === nothing && return nothing
-    if projects isa Vector && basename(dirname(project_file)) in projects
-        return base_project_file
+    home_dir = abspath(homedir())
+    project_dir = abspath(dirname(project_file))
+    current_dir = project_dir
+    # Only stop at home boundary if we started under home
+    started_in_home = startswith(project_dir, home_dir)
+
+    while true
+        parent_dir = dirname(current_dir)
+        # Stop if we've reached root
+        if parent_dir == current_dir
+            return nothing
+        end
+        # Stop if we started in home and have now left it
+        if started_in_home && !startswith(parent_dir, home_dir)
+            return nothing
+        end
+
+        base_project_file = env_project_file(parent_dir)
+        if base_project_file isa String
+            d = parsed_toml(base_project_file)
+            workspace = get(d, "workspace", nothing)::Union{Dict{String, Any}, Nothing}
+            if workspace !== nothing
+                projects = get(workspace, "projects", nothing)::Union{Vector{String}, Nothing, String}
+                if projects isa Vector
+                    # Check if any project in the workspace matches the original project
+                    workspace_root = dirname(base_project_file)
+                    for project in projects
+                        project_path = joinpath(workspace_root, project)
+                        if isdir(project_path)
+                            if samefile(project_path, project_dir)
+                                return base_project_file
+                            end
+                        end
+                    end
+                end
+            end
+        end
+        current_dir = parent_dir
     end
-    return nothing
 end
 
 function project_deps_get(env::String, name::String)::Union{Nothing,PkgId}

doc/src/manual/code-loading.md

@@ -406,7 +406,9 @@ A project file can define a workspace by giving a set of projects that is part o
 projects = ["test", "benchmarks", "docs", "SomePackage"]
 ```
 
-Each subfolder contains its own `Project.toml` file, which may include additional dependencies and compatibility constraints. In such cases, the package manager gathers all dependency information from all the projects in the workspace generating a single manifest file that combines the versions of all dependencies.
+Each project listed in the `projects` array is specified by its relative path from the workspace root. This can be a direct child directory (e.g., `"test"`) or a nested subdirectory (e.g., `"nested/subdir/MyPackage"`). Each project contains its own `Project.toml` file, which may include additional dependencies and compatibility constraints. In such cases, the package manager gathers all dependency information from all the projects in the workspace generating a single manifest file that combines the versions of all dependencies.
+
+When Julia loads a project, it searches upward through parent directories until it reaches the user's home directory to find a workspace that includes that project. This allows workspace projects to be nested at arbitrary depth within the workspace directory tree.
 
 Furthermore, workspaces can be "nested", meaning a project defining a workspace can also be part of another workspace. In this scenario, a single manifest file is still utilized, stored alongside the "root project" (the project that doesn't have another workspace including it). An example file structure could look like this:
 

test/loading.jl

@@ -1658,6 +1658,14 @@ end
        @test isfile(Base.locate_package(id_dev))
        @test Base.identify_package("Devved2") === nothing
 
+       # Test that workspace projects can be specified with subfolder paths
+       # and that base_project searches upward through multiple directory levels
+       empty!(LOAD_PATH)
+       push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "nested", "deep"))
+       proj_file = joinpath(@__DIR__, "project", "SubProject", "nested", "deep", "Project.toml")
+       base_proj = Base.base_project(proj_file)
+       @test base_proj == joinpath(@__DIR__, "project", "SubProject", "Project.toml")
+
     finally
        copy!(LOAD_PATH, old_load_path)
     end

test/project/SubProject/Project.toml

@@ -2,7 +2,7 @@ name = "MyPkg"
 uuid = "0cafdeb2-d7a2-40d0-8d22-4411fcc2c4ee"
 
 [workspace]
-projects = ["sub", "PackageThatIsSub", "test"]
+projects = ["sub", "PackageThatIsSub", "test", "nested/deep"]
 
 [deps]
 Devved = "cbce3a6e-7a3d-4e84-8e6d-b87208df7599"

test/project/SubProject/nested/deep/Project.toml

@@ -0,0 +1,2 @@
+name = "DeepNested"
+uuid = "d5e3a334-7f12-4e5f-9ab8-123456789abc"

test/project/SubProject/nested/deep/src/DeepNested.jl

@@ -0,0 +1,2 @@
+module DeepNested
+end