Use Git.jl for git operations (#2348)

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Documenter prints a more informative warning now if there is unexpected Julia interpolation in the Markdown (e.g. from errant `$` signs). ([#2288], [#2327])
 * Documenter now warns when it encounters invalid keys in the various key-value at-blocks. ([#2306], [#2324])
 * File sizes are now expressed in more human-readable format. ([#2272], [#2344])
+* Documenter now uses [Git.jl](https://github.com/JuliaVersionControl/Git.jl) (as opposed to the system's `git` binary) for Git operations. ([#2348])
 
 ### Fixed
 
@@ -1750,6 +1751,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#2329]: https://github.com/JuliaDocs/Documenter.jl/issues/2329
 [#2330]: https://github.com/JuliaDocs/Documenter.jl/issues/2330
 [#2344]: https://github.com/JuliaDocs/Documenter.jl/issues/2344
+[#2348]: https://github.com/JuliaDocs/Documenter.jl/issues/2348
 [JuliaLang/julia#29344]: https://github.com/JuliaLang/julia/issues/29344
 [JuliaLang/julia#36953]: https://github.com/JuliaLang/julia/issues/36953
 [JuliaLang/julia#38054]: https://github.com/JuliaLang/julia/issues/38054

Project.toml

@@ -9,6 +9,7 @@ Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
 Downloads = "f43a241f-c20a-4ad4-852c-f6b1247861c6"
+Git = "d7ba0133-e1db-5d97-8f8c-041e4b3a1eb2"
 IOCapture = "b5f81e59-6552-4d32-b1f0-c071b021bf89"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
@@ -31,6 +32,7 @@ Base64 = "1.6"
 Dates = "1.6"
 DocStringExtensions = "0.4, 0.5, 0.6, 0.7, 0.8, 0.9"
 Downloads = "1.4"
+Git = "1"
 IOCapture = "0.2"
 InteractiveUtils = "1.6"
 JSON = "0.19, 0.20, 0.21"
@@ -40,13 +42,13 @@ Markdown = "1.6"
 MarkdownAST = "0.1.1"
 Pkg = "1.6"
 PrecompileTools = "1"
-RegistryInstances = "0.1"
-Random = "1.6"
 REPL = "1.6"
+Random = "1.6"
+RegistryInstances = "0.1"
 SHA = "0.7, 1.6"
 Test = "1.6"
-Unicode = "1.6"
 UUIDs = "1.6"
+Unicode = "1.6"
 julia = "1.6"
 
 [extras]

src/Documenter.jl

@@ -22,6 +22,7 @@ import REPL
 import Unicode
 import Pkg
 import RegistryInstances
+import Git
 # Additional imported names
 using Test: @testset, @test
 using DocStringExtensions

src/utilities/utilities.jl

@@ -758,16 +758,24 @@ dropheaders(v::Vector) = map(dropheaders, v)
 dropheaders(other) = other
 
 function git(; nothrow = false, kwargs...)
-    system_git_path = Sys.which("git")
-    if system_git_path === nothing
-        return nothrow ? nothing : error("Unable to find `git`")
-    end
-    # According to the Git man page, the default GIT_TEMPLATE_DIR is at /usr/share/git-core/templates
-    # We need to set this to something so that Git wouldn't pick up the user
-    # templates (e.g. from init.templateDir config).
-    cmd = addenv(`$(system_git_path)`, "GIT_TEMPLATE_DIR" => "/usr/share/git-core/templates")
     # DOCUMENTER_KEY etc are never needed for git operations
-    cmd = addenv(cmd, NO_KEY_ENV)
+    cmd = addenv(Git.git(), NO_KEY_ENV)
+    if Sys.iswindows()
+        cmd = addenv(cmd,
+            # For deploydocs() in particular, we need to use symlinks, but it looks like those
+            # need to be explicitly force-enabled on Windows. So we make sure that we configure
+            # core.symlinks=true via environment variables on that platform.
+            "GIT_CONFIG_COUNT" => "1",
+            "GIT_CONFIG_KEY_0" => "core.symlinks",
+            "GIT_CONFIG_VALUE_0" => "true",
+            # Previously we used to set GIT_TEMPLATE_DIR=/usr/share/git-core/templates on all platforms.
+            # This was so that we wouldn't pick up the user's Git configuration. Git.jl, however, points
+            # the GIT_TEMPLATE_DIR to the artifact directory, and so we're mostly fine without setting
+            # now.. _except_ on Windows, where it doesn't set it. So we still set the environment variable
+            # on Windows, just in case.
+            "GIT_TEMPLATE_DIR" => "/usr/share/git-core/templates",
+        )
+    end
     return cmd
 end