Every verb exits with code 0 even when the directory is missing, deletions fail, or the arguments are invalid

[matt-edmondson]

What's wrong

Program.Main returns void and throws away the parser result (FileDeduplicator/Program.cs:15-21). BaseVerb.Run() and each verb's Run also return void (Verbs/BaseVerb.cs:21,33). As a result, the process exits with 0 on every path except an unhandled crash, including:

• a -p directory that doesn't exist
• Deduplicate finishing with deletion errors (result.Errors.Count > 0)
• the user aborting at a prompt
• unknown or invalid command-line options

Why it matters

A script or scheduled job has no way to tell a failed run from a successful one. For example, FileDeduplicator Deduplicate -p /data && echo done reports success when none of the duplicates were deleted.

Reproduction

These were run against the built ktsu.FileDeduplicator.dll on Linux:

Command	Output	Exit code
Scan -p /nonexistent	Directory not found: /nonexistent / Found 0 file(s).	0
Scan --nope	help and parse errors	0
Running as a user without write permission on the directory holding a duplicate, echo y | Deduplicate -p <dir>	Error deleting …: Access to the path … is denied. / Deleted 0 file(s). / Encountered 1 error(s) during deletion.	0

Suggested fix

• Change Main to static int Main(string[] args) and use ParseArguments(...).MapResult(...), returning 2 when parsing fails.
• Have BaseVerb.Run / Run(T) return an int exit code:
  • 0 on success
  • 1 when the directory is missing, when the user aborts, or when Deduplicate finishes with Errors.Count > 0
• Add tests that check the exit code in each of these cases.

[matt-edmondson]

Triage

• Category: Bug
• Priority: Medium. Scripts and scheduled jobs cannot detect failure: a missing directory, failed deletions and invalid options all exit 0. Interactive use is not affected.
• Area / suggested assignee: Program.Main and BaseVerb.Run / each verb's Run (FileDeduplicator/Program.cs, Verbs/*.cs). Owner: @matt-edmondson
• Duplicates / in progress: not a duplicate. It touches BaseVerb.Run like open PR fix: ask for a new path each time a menu verb runs [patch] #143 and issue Passing -p . explicitly is treated as "no path" and prompts, swallowing the next stdin line as the path #145, so sequence it after fix: ask for a new path each time a menu verb runs [patch] #143 to avoid conflicts.
• Next step: change to static int Main with ParseArguments(...).MapResult(...), returning 2 on a parse failure. Make Run return 1 for a missing directory, an abort, or Errors.Count > 0. Add tests that check the exit code in each case.

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