Add support for --no-export options.

This is intended for use in shell rc files, where variables need to be
set for the current shell but not exported.

2 files changed, 40 insertions, 3 deletions

diff --git a/README.md b/README.md
index 3296195..f5f4439 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,12 @@ I've replaced all of that with a single line:
 
     eval "$(envdir-helper)"
 
+This program also supports setting non-exported shell variables, using the
+`--no-export` flag. This is useful for prompts and other shell configuration
+that should not be propagated through to subshells and other programs. This behaviour is the default if the env directory's name ends in `rc`:
+
+    eval "$(envdir-helper .envdir.rc)"
+
 ## Security
 
 As alluded to above, one of the use cases for this is env-specific tokens. These
diff --git a/envdir/cli.py b/envdir/cli.py
index 3eea246..9a06baf 100644
--- a/envdir/cli.py
+++ b/envdir/cli.py
@@ -10,12 +10,17 @@ import subprocess as sp
 @click.command()
 @click.pass_context
 @click.version_option()
+@click.option(
+    "--export/--no-export",
+    default=None,
+    help="Export generated environment variables [default: --export]",
+)
 @click.argument(
     "envdir",
-    default=pathlib.Path.home() / ".envdir",
+    default=str(pathlib.Path.home() / ".envdir"),
     metavar="DIR",
 )
-def main(context, envdir):
+def main(context, export, envdir):
     r"""Load environment variables from DIR (or ~/.envdir).
 
     For each non-directory entry in DIR, this will output a brief shell script
@@ -40,12 +45,30 @@ def main(context, envdir):
         stderr = click.get_text_stream("stderr")
         click.echo(f"{context.info_name}: skipping {path}: {reason}", file=stderr)
 
+    if export is None:
+        env_script = detect_env_script(
+            envdir, rc=no_export_env_script, default=export_env_script
+        )
+    elif export:
+        env_script = export_env_script
+    else:
+        env_script = no_export_env_script
+
     for name, content in walk_entries(envdir, on_skipped=warn_on_skipped):
         script = env_script(name, content)
         click.echo(script)
 
 
-def env_script(name, content):
+def detect_env_script(path, rc, default):  # pylint: disable=invalid-name
+    """Detect which of two values to use based on whether `path` ends with
+    `"rc"`. If it does, returns `rc`; otherwise, returns `default`.
+    """
+    if path.endswith("rc"):
+        return rc
+    return default
+
+
+def export_env_script(name, content):
     """Given a name and contents, generate a shell script that will set and
     export the corresponding environment variable, with that content."""
     # use sh-friendly syntax here: don't assume `export` can have assignment
@@ -56,6 +79,14 @@ def env_script(name, content):
     return f"{qname}={qcontent}; export {qname}"
 
 
+def no_export_env_script(name, content):
+    """Given a name and contents, generate a shell script that will set and NOT
+    export the corresponding environment variable, with that content."""
+    qname = shlex.quote(name)
+    qcontent = shlex.quote(content)
+    return f"{qname}={qcontent}"
+
+
 def walk_entries(envdir, on_skipped):
     """Yields a name, value pair for each environment file in envdir.