Fix GeoJSON diff regressions in v0.10.1

* Revert `kart diff --output-format=geojson` output handling to the
  pre-0.10.1 behaviour. That is:
  - by default, output goes to stdout
  - if output goes to stdout and there are more than one dataset,
    a usage error occurs (exit code 2) with an error message.
  - `--output=mydirectory` can be used to set a directory into which to
    write output files; one file per dataset.
  - if an existing directory is given, any `*.geojson` files in the
    directory are deleted before creating output files
  - if a path to an existing regular file is given, a usage error
    occurs.

* Remove `kart show --output-format=geojson`. This doesn't work well
  with multiple-dataset commits and was added rather coincidentally
  between 0.10.0 and 0.10.1. We'll remove it for simplicity as it isn't
  very usable; if multiple datasets end up in a single commit, then this
  shows all features together in one FeatureCollection, even if their
  feature schemas are different.

CHANGELOG.md

@@ -6,6 +6,8 @@ _When adding new entries to the changelog, please include issue/PR numbers where
 
 ## 0.10.5 (UNRELEASED)
 
+ * Fixed regressions in `diff -o geojson` since Kart 0.10.1 [#487](https://github.com/koordinates/kart/issues/487)
+ * Removed `kart show -o geojson` [#487](https://github.com/koordinates/kart/issues/487#issuecomment-933561924)
  * Fix for [#478](https://github.com/koordinates/kart/issues/478) `merge --dry-run` raises error
  * Fix for [#483](https://github.com/koordinates/kart/issues/483) `diff` error with Z/M geometries
 

kart/json_diff_writers.py

@@ -262,26 +262,29 @@ class GeojsonDiffWriter(BaseDiffWriter):
 
     @classmethod
     def _check_output_path(cls, repo, output_path):
+        if isinstance(output_path, Path):
+            if output_path.is_file():
+                raise click.BadParameter(
+                    "Output path should be a directory for geojson format.",
+                    param_hint="--output",
+                )
+            if not output_path.exists():
+                output_path.mkdir()
+            else:
+                for p in output_path.glob("*.geojson"):
+                    p.unlink()
+        else:
+            output_path = "-"
         return output_path
 
     def write_diff(self):
-        if isinstance(self.output_path, Path) and self.output_path.is_dir():
-            self.write_file_per_dataset()
-        else:
-            output_obj = {
-                "type": "FeatureCollection",
-                "features": self.filtered_repo_feature_deltas_as_geojson(),
-            }
+        has_changes = False
 
-            dump_json_output(
-                output_obj,
-                self.output_path,
-                json_style=self.json_style,
+        if len(self.all_ds_paths) > 1 and not isinstance(self.output_path, Path):
+            raise click.BadParameter(
+                "Need to specify a directory for geojson with >1 dataset",
+                param_hint="--output",
             )
-        self.write_warnings_footer()
-
-    def write_file_per_dataset(self):
-        has_changes = False
         for ds_path in self.all_ds_paths:
             ds_diff = self.get_dataset_diff(ds_path)
             if not ds_diff:
@@ -291,26 +294,23 @@ def write_file_per_dataset(self):
             has_changes = True
             output_obj = {
                 "type": "FeatureCollection",
-                "features": self.filtered_ds_feature_deltas(ds_path, ds_diff),
+                "features": self.filtered_ds_feature_deltas_as_geojson(
+                    ds_path, ds_diff
+                ),
             }
 
-            ds_output_filename = str(ds_path).replace("/", "__") + ".geojson"
-            ds_output_path = self.output_path / ds_output_filename
+            if self.output_path == "-":
+                ds_output_path = "-"
+            else:
+                ds_output_filename = str(ds_path).replace("/", "__") + ".geojson"
+                ds_output_path = self.output_path / ds_output_filename
             dump_json_output(
                 output_obj,
                 ds_output_path,
                 json_style=self.json_style,
             )
         self.has_changes = has_changes
-
-    def filtered_repo_feature_deltas_as_geojson(self):
-        has_changes = False
-        for ds_path in self.all_ds_paths:
-            ds_diff = self.get_dataset_diff(ds_path)
-            has_changes |= bool(ds_diff)
-            self._warn_about_any_meta_diffs(ds_path, ds_diff)
-            yield from self.filtered_ds_feature_deltas_as_geojson(ds_path, ds_diff)
-        self.has_changes = has_changes
+        self.write_warnings_footer()
 
     def _warn_about_any_meta_diffs(self, ds_path, ds_diff):
         if "meta" in ds_diff:

kart/show.py

@@ -10,9 +10,8 @@
 @click.option(
     "--output-format",
     "-o",
-    type=click.Choice(
-        ["text", "json", "geojson", "quiet", "feature-count", "html", "json-lines"]
-    ),
+    # note: geojson was removed from here because it doesn't work with multiple datasets.
+    type=click.Choice(["text", "json", "quiet", "feature-count", "html", "json-lines"]),
     default="text",
     help=(
         "Output format. 'quiet' disables all output and implies --exit-code.\n"
@@ -39,7 +38,7 @@
     "--json-style",
     type=click.Choice(["extracompact", "compact", "pretty"]),
     default="pretty",
-    help="How to format the output. Only used with -o json or -o geojson",
+    help="How to format the output. Only used with -o json",
 )
 @click.option(
     "--only-feature-count",

tests/test_diff.py

@@ -14,6 +14,7 @@
 H = pytest.helpers.helpers()
 
 DIFF_OUTPUT_FORMATS = ["text", "geojson", "json", "json-lines", "quiet", "html"]
+SHOW_OUTPUT_FORMATS = ["text", "json", "json-lines", "quiet", "html"]
 
 
 def _check_html_output(s):
@@ -1428,7 +1429,7 @@ def test_diff_3way(data_working_copy, cli_runner, insert, request):
         assert len(features) == 1
 
 
-@pytest.mark.parametrize("output_format", DIFF_OUTPUT_FORMATS)
+@pytest.mark.parametrize("output_format", SHOW_OUTPUT_FORMATS)
 def test_show_points_HEAD(output_format, data_archive_readonly, cli_runner):
     """
     Show a patch; ref defaults to HEAD
@@ -1529,7 +1530,7 @@ def test_diff_filtered(data_archive_readonly, cli_runner):
         ]
 
 
-@pytest.mark.parametrize("output_format", DIFF_OUTPUT_FORMATS)
+@pytest.mark.parametrize("output_format", SHOW_OUTPUT_FORMATS)
 def test_show_polygons_initial(output_format, data_archive_readonly, cli_runner):
     """Make sure we can show the initial commit"""
     with data_archive_readonly("polygons"):
@@ -1684,12 +1685,97 @@ def override_get_feature(self, *args, **kwargs):
 
 
 @pytest.mark.parametrize(
-    "output_format", [o for o in DIFF_OUTPUT_FORMATS if o not in {"html", "quiet"}]
+    "output_format", [o for o in SHOW_OUTPUT_FORMATS if o not in {"html", "quiet"}]
 )
-def test_diff_output_to_file(output_format, data_archive, cli_runner):
+def test_show_output_to_file(output_format, data_archive, cli_runner):
     with data_archive("points") as repo_path:
         r = cli_runner.invoke(
             ["show", f"--output-format={output_format}", "--output=out"]
         )
         assert r.exit_code == 0, r
         assert (repo_path / "out").exists()
+
+
+def test_diff_geojson_usage(data_archive, cli_runner, tmp_path):
+    with data_archive("points") as repo_path:
+        # output to stdout
+        r = cli_runner.invoke(
+            ["diff", "--output-format=geojson", "--output=-", "HEAD^..."]
+        )
+        assert r.exit_code == 0, r.stderr
+        # output to stdout (by default)
+        r = cli_runner.invoke(["diff", "--output-format=geojson", "HEAD^..."])
+        assert r.exit_code == 0, r.stderr
+
+        # output to a directory that doesn't yet exist
+        r = cli_runner.invoke(
+            [
+                "diff",
+                "--output-format=geojson",
+                f"--output={tmp_path / 'abc'}",
+                "HEAD^...",
+            ]
+        )
+        assert r.exit_code == 0, r.stderr
+        assert {p.name for p in (tmp_path / "abc").iterdir()} == {
+            "nz_pa_points_topo_150k.geojson"
+        }
+
+        # output to a directory that does exist
+        d = tmp_path / "def"
+        d.mkdir()
+        # this gets left alone
+        (d / "empty.file").write_bytes(b"")
+        # this gets deleted.
+        (d / "some.geojson").write_bytes(b"{}")
+        r = cli_runner.invoke(
+            [
+                "diff",
+                "--output-format=geojson",
+                f"--output={d}",
+                "HEAD^...",
+            ]
+        )
+        assert r.exit_code == 0, r.stderr
+        assert {p.name for p in d.iterdir()} == {
+            "nz_pa_points_topo_150k.geojson",
+            "empty.file",
+        }
+
+        # (add another dataset)
+        with data_archive("gpkg-3d-points") as src:
+            src_gpkg_path = src / "points-3d.gpkg"
+            r = cli_runner.invoke(["-C", repo_path, "import", src_gpkg_path])
+            assert r.exit_code == 0, r.stderr
+
+        # file/stdout output isn't allowed when there are multiple datasets
+        r = cli_runner.invoke(
+            [
+                "diff",
+                "--output-format=geojson",
+                "HEAD^...",
+            ]
+        )
+        assert r.exit_code == 2, r.stderr
+        assert (
+            r.stderr.splitlines()[-1]
+            == "Error: Invalid value for --output: Need to specify a directory for geojson with >1 dataset"
+        )
+
+        # Can't specify an (existing) regular file either
+        myfile = tmp_path / "ghi"
+        myfile.write_bytes(b"")
+        assert myfile.exists()
+        r = cli_runner.invoke(
+            [
+                "diff",
+                "--output-format=geojson",
+                f"--output={myfile}",
+                "HEAD^...",
+            ]
+        )
+        assert r.exit_code == 2, r.stderr
+        assert (
+            r.stderr.splitlines()[-1]
+            == "Error: Invalid value for --output: Output path should be a directory for geojson format."
+        )