feat(bump): add functionality to write the next version to stdout

commitizen/cli.py

@@ -353,6 +353,12 @@ def __call__(
                         "help": "Add additional build-metadata to the version-number",
                         "default": None,
                     },
+                    {
+                        "name": ["--get-next"],
+                        "action": "store_true",
+                        "help": "Determine the next version and write to stdout",
+                        "default": False,
+                    },
                 ],
             },
             {

commitizen/commands/bump.py

@@ -14,6 +14,7 @@
     BumpTagFailedError,
     DryRunExit,
     ExpectedExit,
+    GetNextExit,
     InvalidManualVersion,
     NoCommitsFoundError,
     NoneIncrementExit,
@@ -159,6 +160,7 @@ def __call__(self) -> None:  # noqa: C901
         manual_version = self.arguments["manual_version"]
         build_metadata = self.arguments["build_metadata"]
         increment_mode: str = self.arguments["increment_mode"]
+        get_next: bool = self.arguments["get_next"]
 
         if manual_version:
             if increment:
@@ -190,6 +192,9 @@ def __call__(self) -> None:  # noqa: C901
                     "--prerelease-offset cannot be combined with MANUAL_VERSION"
                 )
 
+            if get_next:
+                raise NotAllowed("--get-next cannot be combined with MANUAL_VERSION")
+
         if major_version_zero:
             if not current_version.release[0] == 0:
                 raise NotAllowed(
@@ -202,6 +207,18 @@ def __call__(self) -> None:  # noqa: C901
                     "--local-version cannot be combined with --build-metadata"
                 )
 
+        # If user specified changelog_to_stdout, they probably want the
+        # changelog to be generated as well, this is the most intuitive solution
+        self.changelog = self.changelog or bool(self.changelog_to_stdout)
+
+        if get_next:
+            if self.changelog:
+                raise NotAllowed(
+                    "--changelog or --changelog-to-stdout is not allowed with --get-next"
+                )
+            # Setting dry_run to prevent any unwanted changes to the repo or files
+            self.dry_run = True
+
         current_tag_version: str = bump.normalize_tag(
             current_version,
             tag_format=tag_format,
@@ -210,10 +227,6 @@ def __call__(self) -> None:  # noqa: C901
 
         is_initial = self.is_initial_tag(current_tag_version, is_yes)
 
-        # If user specified changelog_to_stdout, they probably want the
-        # changelog to be generated as well, this is the most intuitive solution
-        self.changelog = self.changelog or bool(self.changelog_to_stdout)
-
         if manual_version:
             try:
                 new_version = self.scheme(manual_version)
@@ -266,6 +279,16 @@ def __call__(self) -> None:  # noqa: C901
             current_version, new_version, bump_commit_message
         )
 
+        if get_next:
+            if increment is None and new_tag_version == current_tag_version:
+                raise NoneIncrementExit(
+                    "[NO_COMMITS_TO_BUMP]\n"
+                    "The commits found are not eligible to be bumped"
+                )
+
+            out.write(str(new_version))
+            raise GetNextExit()
+
         # Report found information
         information = f"{message}\n" f"tag to create: {new_tag_version}\n"
         if increment:

commitizen/exceptions.py

@@ -67,6 +67,10 @@ class DryRunExit(ExpectedExit):
     pass
 
 
+class GetNextExit(ExpectedExit):
+    pass
+
+
 class NoneIncrementExit(CommitizenException):
     exit_code = ExitCode.NO_INCREMENT
 

docs/commands/bump.md

@@ -285,6 +285,39 @@ You should normally not use this functionality, but if you decide to do, keep in
 * Version `1.2.3+a`, and `1.2.3+b` are the same version! Tools should not use the string after `+` for version calculation. This is probably not a guarantee (example in helm) even tho it is in the spec.
 * It might be problematic having the metadata in place when doing upgrades depending on what tool you use.
 
+### `--get-next`
+
+Provides a way to determine the next version and write it to stdout. This parameter is not compatible with `--changelog`
+and `manual version`.
+
+```bash
+cz bump --get-next
+```
+
+Will output the next version, e.g. `1.2.3`. This can be useful for determining the next version based in CI for non
+production environments/builds.
+
+This behavior differs from the `--dry-run` flag. The `--dry-run` flag provides a more detailed output and can also show
+the changes as they would appear in the changelog file.
+
+The following output is the result of `cz bump --dry-run`:
+
+```
+bump: version 3.28.0 → 3.29.0
+tag to create: v3.29.0
+increment detected: MINOR
+```
+
+The following output is the result of `cz bump --get-next`:
+
+```
+3.29.0
+```
+
+The `--get-next` flag will raise a `NoneIncrementExit` if the found commits are not eligible for a version bump.
+
+For information on how to suppress this exit, see [avoid raising errors](#avoid-raising-errors).
+
 ## Avoid raising errors
 
 Some situations from commitizen raise an exit code different than 0.

tests/commands/test_bump_command.py

@@ -21,6 +21,7 @@
     DryRunExit,
     ExitCode,
     ExpectedExit,
+    GetNextExit,
     InvalidManualVersion,
     NoCommitsFoundError,
     NoneIncrementExit,
@@ -1462,3 +1463,63 @@ def test_bump_command_shows_description_when_use_help_option(
 
     out, _ = capsys.readouterr()
     file_regression.check(out, extension=".txt")
+
+
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_get_next(mocker: MockFixture, capsys):
+    create_file_and_commit("feat: new file")
+
+    testargs = ["cz", "bump", "--yes", "--get-next"]
+    mocker.patch.object(sys, "argv", testargs)
+    with pytest.raises(GetNextExit):
+        cli.main()
+
+    out, _ = capsys.readouterr()
+    assert "0.2.0" in out
+
+    tag_exists = git.tag_exist("0.2.0")
+    assert tag_exists is False
+
+
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_get_next__changelog_is_not_allowed(mocker: MockFixture):
+    create_file_and_commit("feat: new file")
+
+    testargs = ["cz", "bump", "--yes", "--get-next", "--changelog"]
+    mocker.patch.object(sys, "argv", testargs)
+
+    with pytest.raises(NotAllowed):
+        cli.main()
+
+
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_get_next__changelog_to_stdout_is_not_allowed(mocker: MockFixture):
+    create_file_and_commit("feat: new file")
+
+    testargs = ["cz", "bump", "--yes", "--get-next", "--changelog-to-stdout"]
+    mocker.patch.object(sys, "argv", testargs)
+
+    with pytest.raises(NotAllowed):
+        cli.main()
+
+
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_get_next__manual_version_is_not_allowed(mocker: MockFixture):
+    create_file_and_commit("feat: new file")
+
+    testargs = ["cz", "bump", "--yes", "--get-next", "0.2.1"]
+    mocker.patch.object(sys, "argv", testargs)
+
+    with pytest.raises(NotAllowed):
+        cli.main()
+
+
+@pytest.mark.usefixtures("tmp_commitizen_project")
+def test_bump_get_next__no_eligible_commits_raises(mocker: MockFixture):
+    create_file_and_commit("chore: new commit")
+
+    testargs = ["cz", "bump", "--yes", "--get-next"]
+    mocker.patch.object(sys, "argv", testargs)
+
+    with pytest.raises(NoneIncrementExit):
+        cli.main()

tests/commands/test_bump_command/test_bump_command_shows_description_when_use_help_option.txt

@@ -10,7 +10,7 @@ usage: cz bump [-h] [--dry-run] [--files-only] [--local-version] [--changelog]
                [--file-name FILE_NAME] [--prerelease-offset PRERELEASE_OFFSET]
                [--version-scheme {pep440,semver,semver2}]
                [--version-type {pep440,semver,semver2}]
-               [--build-metadata BUILD_METADATA]
+               [--build-metadata BUILD_METADATA] [--get-next]
                [MANUAL_VERSION]
 
 bump semantic version based on the git log
@@ -77,3 +77,4 @@ options:
                         Deprecated, use --version-scheme
   --build-metadata BUILD_METADATA
                         Add additional build-metadata to the version-number
+  --get-next            Determine the next version and write to stdout