Misc #15294: Add warnings for invalid ERB trim modes

• Status: Closed
• Assignee: k0kubun (Takashi Kokubun)

[jsc (Justin Collins)]

Currently, the ERB library will accept any value for the "trim mode". If the trim mode is any string containing %, -, >, <> or an integer 0-2, the appropriate trim mode will be set. If not, no exception or warning is raised.

I had a bug in Brakeman for 1.5 years because I was passing the wrong value as the trim mode. Since the value coincidentally contained - on my test machine, I didn't notice until yesterday.

The attached patch proposes reporting a warning if an invalid trim mode is provided. It does allow a couple invalid modes (you could provide duplicate or conflicting values, like %% or <>>), but I think this is still an improvement over accepting any value at all.

If there is interest, I could spend some time to make it even more strict.

I set the uplevel to 5, which is right if a user is calling ERB.new (most common case?). I don't know if that is the correct approach.

In the future, perhaps this should be an exception instead of a warning.

[k0kubun (Takashi Kokubun)]

• Status changed from Open to Closed

Applied in changeset trunk|r65671.

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erb.rb: warn invalid trim_mode [Misc #15294]

From: Justin Collins [e-mail]

[k0kubun (Takashi Kokubun)]

I thought warning message should provide information that helps to fix the warning, so I modified your patch but applied that in r65671. Thanks.

[jsc (Justin Collins)]

Thank you!