Add single_file option

Split from #158, contributed by @seberg

.coveragerc

@@ -3,9 +3,13 @@ source =
        towncrier
 branch = True
 
-
 [paths]
 source =
    src/
    .tox/*/lib/python*/site-packages/
    .tox/pypy*/site-packages/
+
+[report]
+omit =
+   src/towncrier/__main__.py
+   src/towncrier/test/*

.gitignore

@@ -20,3 +20,4 @@ apidocs/
 .eggs
 .tox/
 .coverage.*
+.vscode

.travis.yml

@@ -29,3 +29,5 @@ matrix:
       env: TOX_ENV=py35-tests
     - python: 3.6
       env: TOX_ENV=py36-tests
+    - python: 3.7
+      env: TOX_ENV=py37-tests

README.rst

@@ -105,3 +105,34 @@ These are:
 
 The start of the filename is the ticket number, and the content is what will end up in the news file.
 For example, if ticket #850 is about adding a new widget, the filename would be ``myproject/newsfragments/850.feature`` and the content would be ``myproject.widget has been added``.
+
+
+Further Options
+---------------
+
+Towncrier has the following global options, which can be specified in the toml file:
+
+```
+[tool.towncrier]
+    package = ""
+    package_dir = "."
+    single_file = true  # if false, filename is formatted like `title_format`.
+    filename = "NEWS.rst"
+    directory = "directory/of/news/fragments"
+    template = "path/to/template.rst"
+    start_line = "start of generated content"
+    title_format = "{name} {version} ({project_date})"  # or false if template includes title
+    issue_format = "format string for {issue} (issue is the first part of fragment name)"
+    underlines: "=-~"
+    wrap = false  # Wrap text to 79 characters
+```
+If a single file is used, the content of this file are overwritten each time.
+
+Furthermore, you can add your own fragment types using:
+```
+[tool.towncrier]
+    [[tool.towncrier.type]]
+        directory = "deprecation"
+        name = "Deprecations"
+        showcontent = true
+```

src/towncrier/_settings.py

@@ -7,6 +7,12 @@
 from collections import OrderedDict
 
 
+class ConfigError(Exception):
+    def __init__(self, *args, **kwargs):
+        self.failing_option = kwargs.get("failing_option")
+        super(ConfigError, self).__init__(*args)
+
+
 _start_string = u".. towncrier release notes start\n"
 _title_format = None
 _template_fname = None
@@ -38,7 +44,7 @@ def load_config_from_file(from_file):
 
 def parse_toml(config):
     if "tool" not in config:
-        raise ValueError("No [tool.towncrier] section.")
+        raise ConfigError("No [tool.towncrier] section.", failing_option="all")
 
     config = config["tool"]["towncrier"]
 
@@ -58,15 +64,25 @@ def parse_toml(config):
         types = _default_types
 
     wrap = config.get("wrap", False)
-    if isinstance(wrap, str):
-        if wrap in ["true", "True", "1"]:
-            wrap = True
-        else:
-            wrap = False
+
+    single_file_wrong = config.get("singlefile")
+    if single_file_wrong:
+        raise ConfigError(
+            "`singlefile` is not a valid option. Did you mean `single_file`?",
+            failing_option="singlefile",
+        )
+
+    single_file = config.get("single_file", True)
+    if not isinstance(single_file, bool):
+        raise ConfigError(
+            "`single_file` option must be a boolean: false or true.",
+            failing_option="single_file",
+        )
 
     return {
         "package": config.get("package", ""),
         "package_dir": config.get("package_dir", "."),
+        "single_file": single_file,
         "filename": config.get("filename", "NEWS.rst"),
         "directory": config.get("directory"),
         "sections": sections,

src/towncrier/_writer.py

@@ -11,17 +11,19 @@
 import os
 
 
-def append_to_newsfile(directory, filename, start_line, top_line, content):
+def append_to_newsfile(directory, filename, start_line, top_line, content, single_file=True):
 
     news_file = os.path.join(directory, filename)
 
-    if not os.path.exists(news_file):
-        existing_content = u""
+    if single_file:
+        if not os.path.exists(news_file):
+            existing_content = u""
+        else:
+            with open(news_file, "rb") as f:
+                existing_content = f.read().decode("utf8")
+        existing_content = existing_content.split(start_line, 1)
     else:
-        with open(news_file, "rb") as f:
-            existing_content = f.read().decode("utf8")
-
-    existing_content = existing_content.split(start_line, 1)
+        existing_content = [u""]
 
     if top_line and top_line in existing_content:
         raise ValueError("It seems you've already produced newsfiles for this version?")

src/towncrier/build.py

@@ -10,6 +10,8 @@
 import os
 import click
 import pkg_resources
+import traceback
+import sys
 
 from datetime import date
 
@@ -60,15 +62,19 @@ def _main(
     project_date,
     answer_yes,
 ):
-    return __main(
-        draft,
-        directory,
-        config_file,
-        project_name,
-        project_version,
-        project_date,
-        answer_yes,
-    )
+    try:
+        return __main(
+            draft,
+            directory,
+            config_file,
+            project_name,
+            project_version,
+            project_date,
+            answer_yes,
+        )
+    except Exception:
+        traceback.print_exc(file=sys.stderr)
+        raise
 
 
 def __main(
@@ -167,12 +173,23 @@ def __main(
     else:
         click.echo("Writing to newsfile...", err=to_err)
         start_line = config["start_line"]
+        news_file = config["filename"]
+
+        if config["single_file"]:
+            # When single_file is enabled, the news file name changes based on the version.
+            news_file = news_file.format(
+                name=project_name,
+                version=project_version,
+                project_date=project_date,
+            )
+
         append_to_newsfile(
-            directory, config["filename"], start_line, top_line, rendered
+            directory, news_file, start_line, top_line, rendered,
+            single_file=config["single_file"]
         )
 
         click.echo("Staging newsfile...", err=to_err)
-        stage_newsfile(directory, config["filename"])
+        stage_newsfile(directory, news_file)
 
         click.echo("Removing news fragments...", err=to_err)
         remove_files(fragment_filenames, answer_yes)

src/towncrier/newsfragments/161.feature

@@ -0,0 +1 @@
+The ``single_file`` option can now be added to the configuration file. When set to ``true``, the filename key can now be formattable with the ``name``, ``version``, and ``project_date`` format variables. This allows subsequent versions to be written out to new files instead of appended to an existing one. 

src/towncrier/test/test_build.py

@@ -373,3 +373,102 @@ def test_no_package_changelog(self):
             """
             ).lstrip(),
         )
+
+    def test_single_file(self):
+        """
+        Enabling the single file mode will write the changelog to a filename
+        that is formatted from the filename args.
+        """
+        runner = CliRunner()
+
+        with runner.isolated_filesystem():
+            with open("pyproject.toml", "w") as f:
+                f.write(
+                    '[tool.towncrier]\n single_file=true\n filename="{version}-notes.rst"'
+                )
+            os.mkdir("newsfragments")
+            with open("newsfragments/123.feature", "w") as f:
+                f.write("Adds levitation")
+
+            result = runner.invoke(
+                _main,
+                [
+                    "--version",
+                    "7.8.9",
+                    "--name",
+                    "foo",
+                    "--date",
+                    "01-01-2001",
+                    "--yes",
+                ],
+            )
+
+            self.assertEqual(0, result.exit_code, result.output)
+            self.assertTrue(os.path.exists("7.8.9-notes.rst"), os.listdir("."))
+            with open("7.8.9-notes.rst", "r") as f:
+                output = f.read()
+
+        self.assertEqual(
+            output,
+            dedent(
+                """
+            foo 7.8.9 (01-01-2001)
+            ======================
+
+            Features
+            --------
+
+            - Adds levitation (#123)
+            """
+            ).lstrip(),
+        )
+
+    def test_single_file_false(self):
+        """
+        If formatting arguments are given in the filename arg and single_file is
+        false, the filename will not be formatted.
+        """
+        runner = CliRunner()
+
+        with runner.isolated_filesystem():
+            with open("pyproject.toml", "w") as f:
+                f.write(
+                    '[tool.towncrier]\n single_file=false\n filename="{version}-notes.rst"'
+                )
+            os.mkdir("newsfragments")
+            with open("newsfragments/123.feature", "w") as f:
+                f.write("Adds levitation")
+
+            result = runner.invoke(
+                _main,
+                [
+                    "--version",
+                    "7.8.9",
+                    "--name",
+                    "foo",
+                    "--date",
+                    "01-01-2001",
+                    "--yes",
+                ],
+            )
+
+            self.assertEqual(0, result.exit_code, result.output)
+            self.assertTrue(os.path.exists("{version}-notes.rst"), os.listdir("."))
+            self.assertFalse(os.path.exists("7.8.9-notes.rst"), os.listdir("."))
+            with open("{version}-notes.rst", "r") as f:
+                output = f.read()
+
+        self.assertEqual(
+            output,
+            dedent(
+                """
+            foo 7.8.9 (01-01-2001)
+            ======================
+
+            Features
+            --------
+
+            - Adds levitation (#123)
+            """
+            ).lstrip(),
+        )

src/towncrier/test/test_settings.py

@@ -4,8 +4,9 @@
 from twisted.trial.unittest import TestCase
 
 import os
+from textwrap import dedent
 
-from .._settings import load_config
+from .._settings import load_config, ConfigError
 
 
 class TomlSettingsTests(TestCase):
@@ -28,3 +29,69 @@ def test_base(self):
         self.assertEqual(config["package_dir"], ".")
         self.assertEqual(config["filename"], "NEWS.rst")
         self.assertEqual(config["underlines"], ["=", "-", "~"])
+
+    def test_missing(self):
+        """
+        If the config file doesn't have the correct toml key, we error.
+        """
+        temp = self.mktemp()
+        os.makedirs(temp)
+
+        with open(os.path.join(temp, "pyproject.toml"), "w") as f:
+            f.write(
+                dedent(
+                    """
+                [something.else]
+                blah='baz'
+                """
+                )
+            )
+
+        with self.assertRaises(ConfigError) as e:
+            load_config(temp)
+
+        self.assertEqual(e.exception.failing_option, "all")
+
+    def test_incorrect_single_file(self):
+        """
+        single_file must be a bool.
+        """
+        temp = self.mktemp()
+        os.makedirs(temp)
+
+        with open(os.path.join(temp, "pyproject.toml"), "w") as f:
+            f.write(
+                dedent(
+                    """
+                [tool.towncrier]
+                single_file = "a"
+                """
+                )
+            )
+
+        with self.assertRaises(ConfigError) as e:
+            load_config(temp)
+
+        self.assertEqual(e.exception.failing_option, "single_file")
+
+    def test_mistype_singlefile(self):
+        """
+        singlefile is not accepted, single_file is.
+        """
+        temp = self.mktemp()
+        os.makedirs(temp)
+
+        with open(os.path.join(temp, "pyproject.toml"), "w") as f:
+            f.write(
+                dedent(
+                    """
+                [tool.towncrier]
+                singlefile = "a"
+                """
+                )
+            )
+
+        with self.assertRaises(ConfigError) as e:
+            load_config(temp)
+
+        self.assertEqual(e.exception.failing_option, "singlefile")