修改代码后Snakemake出现MissingRuleException问题求助

Let’s work through your Snakemake issues one by one—you’ve got two separate problems here: a misused command that’s throwing errors, and --list-code-changes not picking up your modified Python scripts like you expect.

1. Fixing the Error with snakemake -n -R 'snakemake --list-code-changes' #

The -R flag in Snakemake is designed to take rule names, wildcard patterns, or target files as arguments—not a full nested snakemake command. That’s why you’re hitting an error here. If your goal is to rerun only rules affected by code changes, you don’t need to nest commands. Here’s how to do it properly:

First, get the list of rules affected by code changes:

snakemake --list-code-changes

Then pass that list directly to -R using command substitution (works in bash/zsh):

snakemake -n -R $(snakemake --list-code-changes)

Or, even easier—use Snakemake’s built-in auto-rerun trigger for code changes, which removes the need to manually list rules:

snakemake -n --rerun-triggers code

The -n flag runs a dry run, so you can confirm which rules would be rerun before executing the actual pipeline.

2. Why --list-code-changes Returns Empty (and How to Fix It) #

By default, Snakemake tracks code changes in:

• The main Snakefile
• Scripts linked via the script: directive in rules
• Python modules imported in the Snakefile or rule scripts

If your modified Python scripts aren’t being detected, try these fixes:

a. Explicitly link scripts to rules #

If you’re calling Python scripts via shell: (e.g., shell: "python my_script.py {input}"), Snakemake won’t automatically track those scripts as code dependencies. Fix this by either:

• Using the script: directive instead (Snakemake handles tracking automatically):

  rule my_rule:
      input: "data.in"
      output: "data.out"
      script: "my_script.py"
  

• Or declaring the script as a code dependency with the code: directive:

  rule my_rule:
      input: "data.in"
      output: "data.out"
      code: "my_script.py"
      shell: "python my_script.py {input} {output}"
  

This tells Snakemake to monitor my_script.py for changes and flag the rule for rerun when it’s modified.

b. Check imported modules #

If your Python scripts are imported as modules (e.g., import my_module in your Snakefile), Snakemake should detect changes automatically—but make sure:

• The module is in a directory that’s in Python’s path (add it with sys.path.append("./my_modules") in your Snakefile if needed)
• You’re not using relative imports that Snakemake can’t track

c. Clear cached metadata & update Snakemake #

Sometimes cached metadata can prevent Snakemake from detecting changes. Clear it with:

snakemake --list-code-changes --cleanup-metadata

Also, older Snakemake versions had limitations in code change detection. Upgrade to the latest stable version to rule out bugs:

pip install --upgrade snakemake

内容的提问来源于stack exchange，提问作者Julio