Don't always run auto-alt (and -perms) after invoking git command

Improve performance (#505) by only running auto-alt (and auto-perms)
when HEAD has changed after calling a git command, e.g. after committing
or pulling new changes.

Also use this new information to remove stale symlinks when an alt file
has been removed.

test/test_alt.py

@@ -248,7 +248,12 @@ def test_auto_alt(runner, yadm_cmd, paths, autoalt):
         os.system(" ".join(yadm_cmd("config", "yadm.auto-alt", autoalt)))
 
     utils.create_alt_files(paths, "##default")
-    run = runner(yadm_cmd("status"))
+
+    # Add and commit a file to trigger auto alt
+    paths.work.join("somefile").write("somedata")
+    runner(yadm_cmd("add", "somefile"), report=False)
+
+    run = runner(yadm_cmd("commit", "-m", "msg"))
     assert run.success
     assert run.err == ""
     linked = utils.parse_alt_output(run.out)
@@ -353,6 +358,26 @@ def test_stale_link_removal(runner, yadm_cmd, paths):
         assert str(source_file) not in linked
 
 
+@pytest.mark.usefixtures("ds1_copy")
+def test_deleted_file_link_removal(runner, yadm_cmd, paths):
+    """Link to deleted file is removed"""
+
+    utils.create_alt_files(paths, "##default")
+    run = runner(yadm_cmd("alt", "-d"))
+    assert run.success
+
+    # Remove one alt file
+    run = runner(yadm_cmd("rm", TEST_PATHS[0] + "##default"))
+    assert run.success
+    run = runner(yadm_cmd("commit", "-m", "remove"))
+    assert run.success
+
+    # And verify that the symlink has been removed
+    link_file = paths.work.join(TEST_PATHS[0])
+    with pytest.raises(OSError):
+        link_file.lstat()
+
+
 @pytest.mark.usefixtures("ds1_copy")
 def test_legacy_dir_link_removal(runner, yadm_cmd, paths):
     """Legacy link to alternative dir is removed
@@ -414,6 +439,8 @@ def test_template_overwrite_symlink(runner, yadm_cmd, paths, tst_sys):
     assert run.success
     assert run.err == ""
     assert run.out == ""
+    run = runner(yadm_cmd("commit", "-m", "msg"))
+    assert run.success
     assert not link.islink()
     assert target.read().strip() == "target"
     assert link.read().strip() == "test-data"
@@ -432,6 +459,8 @@ def test_ensure_alt_path(runner, paths, style):
     assert run.success
     assert run.err == ""
     assert run.out == ""
+    run = runner([paths.pgm, "-Y", yadm_dir, "--yadm-data", yadm_data, "commit", "-m", "msg"])
+    assert run.success
     assert paths.work.join(filename).read().strip() == "test-data"
 
 

test/test_config.py

@@ -32,12 +32,12 @@ def test_config_read_missing(runner, yadm_cmd):
     """Read missing attribute
 
     Display an empty value
-    Exit with 0
+    Exit with 1
     """
 
     run = runner(yadm_cmd("config", TEST_KEY))
 
-    assert run.success
+    assert not run.success
     assert run.err == ""
     assert run.out == ""
 

test/test_perms.py

@@ -35,13 +35,15 @@ def test_perms(runner, yadm_cmd, paths, ds1, autoperms):
     for private in privatepaths + insecurepaths:
         assert not oct(private.stat().mode).endswith("00"), "Path started secured"
 
-    cmd = "perms"
+    cmd = ["perms"]
     if autoperms != "notest":
-        cmd = "status"
-    run = runner(yadm_cmd(cmd), env={"HOME": paths.work})
+        run = runner(yadm_cmd("add", "efile1"), report=False)
+        assert run.success
+        cmd = ["-c", "user.name=Yadm", "commit", "-m", "msg"]
+    run = runner(yadm_cmd(*cmd), env={"HOME": paths.work})
     assert run.success
     assert run.err == ""
-    if cmd == "perms":
+    if autoperms == "notest":
         assert run.out == ""
 
     # these paths should be secured if processing perms

test/test_unit_report_invalid_alts.py

@@ -22,7 +22,7 @@ def test_report_invalid_alts(runner, yadm, valid, previous):
         report_invalid_alts
     """
     run = runner(command=["bash"], inp=script)
-    assert run.success
+    assert run.success == (valid and not previous)
     assert run.out == ""
     if not valid and not previous:
         assert "WARNING" in run.err