manifest: generalize --json as --format=<format>

This will make it easier to add more formats without exploding the
common --xxx space and checking a large set of boolean flags.

Also fill out the test coverage while we're here.

Bug: b/412725063
Change-Id: I754013dc6cb3445f8a0979cefec599d55dafdcff
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/471941
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

3 files changed, 195 insertions, 8 deletions

diff --git a/man/repo-manifest.1 b/man/repo-manifest.1
index f2f7290d..74e09145 100644
--- a/man/repo-manifest.1
+++ b/man/repo-manifest.1
@@ -30,8 +30,8 @@ if in \fB\-r\fR mode, do not write the dest\-branch field
 (only of use if the branch names for a sha1 manifest
 are sensitive)
 .TP
-\fB\-\-json\fR
-output manifest in JSON format (experimental)
+\fB\-\-format\fR=\fI\,FORMAT\/\fR
+output format: xml, json (default: xml)
 .TP
 \fB\-\-pretty\fR
 format output for humans to read
@@ -78,6 +78,10 @@ set to the ref we were on when the manifest was generated. The 'dest\-branch'
 attribute is set to indicate the remote ref to push changes to via 'repo
 upload'.
 .PP
+Multiple output formats are supported via \fB\-\-format\fR. The default output is XML,
+and formats are generally "condensed". Use \fB\-\-pretty\fR for more human\-readable
+variations.
+.PP
 repo Manifest Format
 .PP
 A repo manifest describes the structure of a repo client; that is the
diff --git a/subcmds/manifest.py b/subcmds/manifest.py
index bb6dc930..9786580a 100644
--- a/subcmds/manifest.py
+++ b/subcmds/manifest.py
@@ -12,7 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import enum
 import json
+import optparse
 import os
 import sys
 
@@ -23,6 +25,16 @@ from repo_logging import RepoLogger
 logger = RepoLogger(__file__)
 
 
+class OutputFormat(enum.Enum):
+    """Type for the requested output format."""
+
+    # Canonicalized manifest in XML format.
+    XML = enum.auto()
+
+    # Canonicalized manifest in JSON format.
+    JSON = enum.auto()
+
+
 class Manifest(PagedCommand):
     COMMON = False
     helpSummary = "Manifest inspection utility"
@@ -42,6 +54,10 @@ revisions set to the current commit hash.  These are known as
 In this case, the 'upstream' attribute is set to the ref we were on
 when the manifest was generated.  The 'dest-branch' attribute is set
 to indicate the remote ref to push changes to via 'repo upload'.
+
+Multiple output formats are supported via --format.  The default output
+is XML, and formats are generally "condensed".  Use --pretty for more
+human-readable variations.
 """
 
     @property
@@ -86,11 +102,21 @@ to indicate the remote ref to push changes to via 'repo upload'.
             "(only of use if the branch names for a sha1 manifest are "
             "sensitive)",
         )
+        # Replaced with --format=json.  Kept for backwards compatibility.
+        # Can delete in Jun 2026 or later.
         p.add_option(
             "--json",
-            default=False,
-            action="store_true",
-            help="output manifest in JSON format (experimental)",
+            action="store_const",
+            dest="format",
+            const=OutputFormat.JSON.name.lower(),
+            help=optparse.SUPPRESS_HELP,
+        )
+        formats = tuple(x.lower() for x in OutputFormat.__members__.keys())
+        p.add_option(
+            "--format",
+            default=OutputFormat.XML.name.lower(),
+            choices=formats,
+            help=f"output format: {', '.join(formats)} (default: %default)",
         )
         p.add_option(
             "--pretty",
@@ -121,6 +147,8 @@ to indicate the remote ref to push changes to via 'repo upload'.
         if opt.manifest_name:
             self.manifest.Override(opt.manifest_name, False)
 
+        output_format = OutputFormat[opt.format.upper()]
+
         for manifest in self.ManifestList(opt):
             output_file = opt.output_file
             if output_file == "-":
@@ -135,8 +163,7 @@ to indicate the remote ref to push changes to via 'repo upload'.
 
             manifest.SetUseLocalManifests(not opt.ignore_local_manifests)
 
-            if opt.json:
-                logger.warning("warning: --json is experimental!")
+            if output_format == OutputFormat.JSON:
                 doc = manifest.ToDict(
                     peg_rev=opt.peg_rev,
                     peg_rev_upstream=opt.peg_rev_upstream,
@@ -152,7 +179,7 @@ to indicate the remote ref to push changes to via 'repo upload'.
                     "separators": (",", ": ") if opt.pretty else (",", ":"),
                     "sort_keys": True,
                 }
-                fd.write(json.dumps(doc, **json_settings))
+                fd.write(json.dumps(doc, **json_settings) + "\n")
             else:
                 manifest.Save(
                     fd,
diff --git a/tests/test_subcmds_manifest.py b/tests/test_subcmds_manifest.py
new file mode 100644
index 00000000..9b1ffb30
--- /dev/null
+++ b/tests/test_subcmds_manifest.py
@@ -0,0 +1,156 @@
+# Copyright (C) 2025 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for the subcmds/manifest.py module."""
+
+import json
+from pathlib import Path
+from unittest import mock
+
+import manifest_xml
+from subcmds import manifest
+
+
+_EXAMPLE_MANIFEST = """\
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest>
+  <remote name="test-remote" fetch="http://localhost" />
+  <default remote="test-remote" revision="refs/heads/main" />
+  <project name="repohooks" path="src/repohooks"/>
+  <repo-hooks in-project="repohooks" enabled-list="a, b"/>
+</manifest>
+"""
+
+
+def _get_cmd(repodir: Path) -> manifest.Manifest:
+    """Instantiate a manifest command object to test."""
+    manifests_git = repodir / "manifests.git"
+    manifests_git.mkdir()
+    (manifests_git / "config").write_text(
+        """
+[remote "origin"]
+\turl = http://localhost/manifest
+"""
+    )
+    client = manifest_xml.RepoClient(repodir=str(repodir))
+    git_event_log = mock.MagicMock(ErrorEvent=mock.Mock(return_value=None))
+    return manifest.Manifest(
+        repodir=client.repodir,
+        client=client,
+        manifest=client.manifest,
+        outer_client=client,
+        outer_manifest=client.manifest,
+        git_event_log=git_event_log,
+    )
+
+
+def test_output_format_xml_file(tmp_path):
+    """Test writing XML to a file."""
+    path = tmp_path / "manifest.xml"
+    path.write_text(_EXAMPLE_MANIFEST)
+    outpath = tmp_path / "output.xml"
+    cmd = _get_cmd(tmp_path)
+    opt, args = cmd.OptionParser.parse_args(["--output-file", str(outpath)])
+    cmd.Execute(opt, args)
+    # Normalize the output a bit as we don't exactly care.
+    normalize = lambda data: "\n".join(
+        x.strip() for x in data.splitlines() if x.strip()
+    )
+    assert (
+        normalize(outpath.read_text())
+        == """<?xml version="1.0" encoding="UTF-8"?>
+<manifest>
+<remote name="test-remote" fetch="http://localhost"/>
+<default remote="test-remote" revision="refs/heads/main"/>
+<project name="repohooks" path="src/repohooks"/>
+<repo-hooks in-project="repohooks" enabled-list="a b"/>
+</manifest>"""
+    )
+
+
+def test_output_format_xml_stdout(tmp_path, capsys):
+    """Test writing XML to stdout."""
+    path = tmp_path / "manifest.xml"
+    path.write_text(_EXAMPLE_MANIFEST)
+    cmd = _get_cmd(tmp_path)
+    opt, args = cmd.OptionParser.parse_args(["--format", "xml"])
+    cmd.Execute(opt, args)
+    # Normalize the output a bit as we don't exactly care.
+    normalize = lambda data: "\n".join(
+        x.strip() for x in data.splitlines() if x.strip()
+    )
+    stdout = capsys.readouterr().out
+    assert (
+        normalize(stdout)
+        == """<?xml version="1.0" encoding="UTF-8"?>
+<manifest>
+<remote name="test-remote" fetch="http://localhost"/>
+<default remote="test-remote" revision="refs/heads/main"/>
+<project name="repohooks" path="src/repohooks"/>
+<repo-hooks in-project="repohooks" enabled-list="a b"/>
+</manifest>"""
+    )
+
+
+def test_output_format_json(tmp_path, capsys):
+    """Test writing JSON."""
+    path = tmp_path / "manifest.xml"
+    path.write_text(_EXAMPLE_MANIFEST)
+    cmd = _get_cmd(tmp_path)
+    opt, args = cmd.OptionParser.parse_args(["--format", "json"])
+    cmd.Execute(opt, args)
+    obj = json.loads(capsys.readouterr().out)
+    assert obj == {
+        "default": {"remote": "test-remote", "revision": "refs/heads/main"},
+        "project": [{"name": "repohooks", "path": "src/repohooks"}],
+        "remote": [{"fetch": "http://localhost", "name": "test-remote"}],
+        "repo-hooks": {"enabled-list": "a b", "in-project": "repohooks"},
+    }
+
+
+def test_output_format_json_pretty(tmp_path, capsys):
+    """Test writing pretty JSON."""
+    path = tmp_path / "manifest.xml"
+    path.write_text(_EXAMPLE_MANIFEST)
+    cmd = _get_cmd(tmp_path)
+    opt, args = cmd.OptionParser.parse_args(["--format", "json", "--pretty"])
+    cmd.Execute(opt, args)
+    stdout = capsys.readouterr().out
+    assert (
+        stdout
+        == """\
+{
+  "default": {
+    "remote": "test-remote",
+    "revision": "refs/heads/main"
+  },
+  "project": [
+    {
+      "name": "repohooks",
+      "path": "src/repohooks"
+    }
+  ],
+  "remote": [
+    {
+      "fetch": "http://localhost",
+      "name": "test-remote"
+    }
+  ],
+  "repo-hooks": {
+    "enabled-list": "a b",
+    "in-project": "repohooks"
+  }
+}
+"""
+    )