setup.py: improve handling of PYMUPDF_SETUP_MUPDF_BUILD when it starts with git:.

We now use pipcl.git_get(), which works much better than the previous code.

Author: julian-smith-artifex-com

setup.py

@@ -88,11 +88,12 @@
             Empty string:
                 Build PyMuPDF with the system MuPDF.
             A string starting with 'git:':
-                Use `git clone` to get a MuPDF checkout. We use the
-                string in the git clone command; it must contain the git
-                URL from which to clone, and can also contain other `git
-                clone` args, for example:
-                    PYMUPDF_SETUP_MUPDF_BUILD="git:--branch master https://github.com/ArtifexSoftware/mupdf.git"
+                We use `git` commands to clone/update a local MuPDF checkout.
+                Should match `git:[--branch <branch>][--tag <tag>][<remote>]`.
+                If <remote> is omitted we use a default.
+                For example:
+                    PYMUPDF_SETUP_MUPDF_BUILD="git:--branch master"
+                Passed as <remote> arg to pipcl.git_get().
             Otherwise:
                 Location of mupdf directory.
     
@@ -425,7 +426,7 @@ def git_patch(directory, patch, hard=False):
 
 mupdf_tgz = os.path.abspath( f'{__file__}/../mupdf.tgz')
 
-def get_mupdf_internal(out, location=None, sha=None, local_tgz=None):
+def get_mupdf_internal(out, location=None, local_tgz=None):
     '''
     Gets MuPDF as either a .tgz or a local directory.
     
@@ -438,8 +439,6 @@ def get_mupdf_internal(out, location=None, sha=None, local_tgz=None):
             If starts with 'git:', should be remote git location.
             Otherwise if containing '://' should be URL for .tgz.
             Otherwise should path of local mupdf checkout.
-        sha:
-            If not None and we use git clone, we checkout this sha.
         local_tgz:
             If not None, must be local .tgz file.
     Returns:
@@ -451,7 +450,7 @@ def get_mupdf_internal(out, location=None, sha=None, local_tgz=None):
             default location.
                 
     '''
-    log(f'get_mupdf_internal(): {out=} {location=} {sha=}')
+    log(f'get_mupdf_internal(): {out=} {location=}')
     assert out in ('dir', 'tgz')
     if location is None:
         location = f'https://mupdf.com/downloads/archive/mupdf-{version_mupdf}-source.tar.gz'
@@ -465,21 +464,15 @@ def get_mupdf_internal(out, location=None, sha=None, local_tgz=None):
     if local_tgz:
         assert os.path.isfile(local_tgz)
     elif location.startswith( 'git:'):
-        location_git = location[4:]
         local_dir = 'mupdf-git'
+        pipcl.git_get(location, local_dir, default_remote='https://github.com/ArtifexSoftware/mupdf.git')
 
-        # Try to update existing checkout.
-        e = run(f'cd {local_dir} && git pull && git submodule update --init', check=False)
-        if e:
-            # No existing git checkout, so do a fresh clone.
-            _fs_remove(local_dir)
-            gitargs = location[4:]
-            run(f'git clone --recursive --depth 1 --shallow-submodules {gitargs} {local_dir}')
-
         # Show sha of checkout.
-        run( f'cd {local_dir} && git show --pretty=oneline|head -n 1', check=False)
-        if sha:
-            run( f'cd {local_dir} && git checkout {sha}')
+        run(
+                f'cd {local_dir} && git show --pretty=oneline|head -n 1',
+                check = False,
+                prefix = 'mupdf git id: ',
+                )
     elif '://' in location:
         # Download .tgz.
         local_tgz = os.path.basename( location)