Add branch sub-option for git project vcs in bdep-new

Also fix tests which failed if for the initial branch git-init defaults to
the name other than 'master'.

5 files changed, 112 insertions, 11 deletions

diff --git a/bdep/git.cxx b/bdep/git.cxx
index cc697b3..f9bdc04 100644
--- a/bdep/git.cxx
+++ b/bdep/git.cxx
@@ -24,10 +24,8 @@ namespace bdep
   static optional<semantic_version>           bun_git_ver;
 #endif
 
-  // Check that git is at least of the specified minimum supported version.
-  //
-  void
-  git_check_version (const semantic_version& min_ver, bool system)
+  bool
+  git_try_check_version (const semantic_version& min_ver, bool system)
   {
     // Query and cache git version on the first call.
     //
@@ -50,9 +48,24 @@ namespace bdep
     // Note that we don't expect the min_ver to contain the build component,
     // that doesn't matter functionality-wise for git.
     //
-    if (*gv < min_ver)
+    return *gv >= min_ver;
+  }
+
+  // As above but issue diagnostics and fail if git is older than the
+  // specified minimum supported version.
+  //
+  void
+  git_check_version (const semantic_version& min_ver, bool system)
+  {
+    if (!git_try_check_version (min_ver, system))
+    {
+      optional<semantic_version>& gv (system ? sys_git_ver : bun_git_ver);
+
+      assert (gv); // Must have been cached by git_try_check_version().
+
       fail << "unsupported git version " << *gv <<
         info << "minimum supported version is " << min_ver << endf;
+    }
   }
 
   // Return git process path and the --exec-path option, if it is required for
diff --git a/bdep/git.hxx b/bdep/git.hxx
index b7703ea..30baf69 100644
--- a/bdep/git.hxx
+++ b/bdep/git.hxx
@@ -67,18 +67,50 @@ namespace bdep
 
   // Run git process.
   //
+  // Pass NULL as the repository argument if the git command is not
+  // repository-specific (e.g., init).
+  //
   template <typename... A>
   void
   run_git (const semantic_version&,
            bool system,
            bool progress,
-           const dir_path& repo,
+           const dir_path* repo,
            A&&... args);
 
   template <typename... A>
   inline void
   run_git (const semantic_version& min_ver,
            bool system,
+           const dir_path* repo,
+           A&&... args)
+  {
+    run_git (min_ver,
+             system,
+             true /* progress */,
+             repo,
+             forward<A> (args)...);
+  }
+
+  template <typename... A>
+  inline void
+  run_git (const semantic_version& min_ver,
+           bool system,
+           bool progress,
+           const dir_path& repo,
+           A&&... args)
+  {
+    run_git (min_ver,
+             system,
+             progress,
+             &repo,
+             forward<A> (args)...);
+  }
+
+  template <typename... A>
+  inline void
+  run_git (const semantic_version& min_ver,
+           bool system,
            const dir_path& repo,
            A&&... args)
   {
@@ -173,6 +205,12 @@ namespace bdep
   template <typename... A>
   void
   git_push (const common_options&, const dir_path& repo, A&&... args);
+
+  // Return true if git is at least of the specified minimum supported
+  // version.
+  //
+  bool
+  git_try_check_version (const semantic_version&, bool system);
 }
 
 #include <bdep/git.ixx>
diff --git a/bdep/git.txx b/bdep/git.txx
index ef81bd8..2af8e1f 100644
--- a/bdep/git.txx
+++ b/bdep/git.txx
@@ -8,7 +8,7 @@ namespace bdep
   run_git (const semantic_version& min_ver,
            bool system,
            bool progress,
-           const dir_path& repo,
+           const dir_path* repo,
            A&&... args)
   {
     // Unfortunately git doesn't have any kind of a no-progress option but
@@ -30,10 +30,12 @@ namespace bdep
     //
     process pr (start_git (min_ver,
                            system,
-                           repo,
                            0   /* stdin  */,
                            err /* stdout */,
                            err /* stderr */,
+                           (repo != nullptr
+                            ? cstrings ({"-C", repo->string ().c_str ()})
+                            : cstrings ()),
                            forward<A> (args)...));
 
     bool io (false);
diff --git a/bdep/new.cli b/bdep/new.cli
index 8f3b094..c6dc8ee 100644
--- a/bdep/new.cli
+++ b/bdep/new.cli
@@ -501,7 +501,12 @@ namespace bdep
      \li|\cb{git}
 
          Initialize a \cb{git(1)} repository inside the project and generate
-         \cb{.gitignore} files.||
+         \cb{.gitignore} files. Recognized version control system sub-options:|
+
+     \li|\n\ \ \ \c{\b{branch=}\i{name}}
+
+         Use the specified name for the initial branch in the newly created
+         repository.||
 
      \dl|
 
@@ -632,6 +637,7 @@ namespace bdep
   //
   class cmd_new_git_options
   {
+    string branch;
   };
 
   class cmd_new_none_options
diff --git a/bdep/new.cxx b/bdep/new.cxx
index 2c954fc..a2d2ad4 100644
--- a/bdep/new.cxx
+++ b/bdep/new.cxx
@@ -24,6 +24,13 @@ using namespace butl;
 
 namespace bdep
 {
+  // While we don't have any specific requirements for git version here, let's
+  // use the lowest common denominator for other bdep commands. Note that
+  // *_git() functions require the minimum supported git version as an
+  // argument.
+  //
+  static const semantic_version git_ver {2, 1, 0};
+
   // License id to full name map.
   //
   // Used for the license full name search for the auto-detected and
@@ -1235,8 +1242,43 @@ cmd_new (cmd_new_options&& o, cli::group_scanner& args)
   {
     switch (vc)
     {
-    case vcs::git:  run ("git", "init", "-q", out); break;
-    case vcs::none:                                 break;
+    case vcs::git:
+      {
+        const cmd_new_git_options& opt (vc.git_opt);
+
+        // If the branch name is specified, then pass it to git-init using the
+        // --initial-branch option if the git version is at least 2.28.0 (the
+        // one which has introduced this option). Otherwise, run git-init
+        // normally and then change HEAD to refer to the requested name. Note
+        // that the branch will only be created on the first commit.
+        //
+        if (opt.branch_specified ())
+        {
+          if (git_try_check_version (semantic_version {2, 28, 0},
+                                     true /* system */))
+          {
+            run_git (git_ver, true /* system */, nullptr /* repo */,
+                     "init", "-q", "--initial-branch", opt.branch (), out);
+          }
+          else
+          {
+            run_git (git_ver, true /* system */, nullptr /* repo */,
+                     "init", "-q", out);
+
+            run_git (git_ver, true /* system */, out,
+                     "symbolic-ref",
+                     "-q",
+                     "HEAD",
+                     "refs/heads/" + opt.branch ());
+          }
+        }
+        else
+          run_git (git_ver, true /* system */, nullptr /* repo */,
+                   "init", "-q", out);
+
+        break;
+      }
+    case vcs::none: break;
     }
   }