Author Archives: Jay Jay

About Jay Jay

Hi there. My name is John Elliot V. My friends call me Jay Jay. I talk about technology on my blog at blog.jj5.net and make videos about electronics on my YouTube channel @InTheLabWithJayJay.

Most bugs are in your error handling code

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While reading What tools made you better programmer I came across a link to Error Handling in a Correctness-Critical Rust Project which included these two tidbits:

almost all (92%) of the catastrophic system failures are the result of incorrect handling of non-fatal errors explicitly signaled in software.

in 58% of the catastrophic failures, the underlying faults could easily have been detected through simple testing of error handling code.

Konsole column width

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So after having read this I was trying to configure Konsole by editing my config files under

~/.local/share/konsole

and I couldn’t get my column width config to apply.

The problem was that I was configuring column width with the TerminalCols setting, but the correct setting is actually TerminalColumns, which was difficult to figure out! Not sure how I managed to get that wrong in the first place, but it’s fixed now.

My new Konsole dimension settings are:

TerminalColumns=100
TerminalRows=42

salt stack file_tree.py

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So in my version of salt, v2017.7.4 (Nitrogen), I was getting this error when I tried to use the file_tree ext_pillar:

Failed to load ext_pillar file_tree: must be str, not bytes

So I monkey patched my version of /usr/lib/python3/dist-packages/salt/pillar/file_tree.py, changing the file from binary to text:

            contents = ''
            try:
                # 2020-05-15 jj5 - changed 'rb' to 'r', will only work with text files...
                with salt.utils.fopen(file_path, 'r') as fhr:
                    buf = fhr.read(__opts__['file_buffer_size'])
                    while buf:
                        contents += buf
                        buf = fhr.read(__opts__['file_buffer_size'])
                    if contents.endswith('\n') \
                            and _check_newline(prefix,
                                               file_name,
                                               keep_newline):
                        contents = contents[:-1]

HTML forms

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Found a cool series of articles: How to Build HTML Forms Right. Only the first two of five articles have been published so far, but I’m looking forward to the next three. The articles are about how to do forms right in HTML 5.

The articles are rich with links, click through for heaps of info. Some things that I found:

How to clear dashed lines from LibreOffice Calc

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I don’t know how it happened but suddenly I found I had this annoying situation in LibreOffice Calc whereby there were “dashed lines” repeating regularly throughout my sheets. Turns out it was display of page breaks. Anyway I found this and the solution was:

Tools ▸ Options ▸ LibreOffice Calc ▸ View ▸ Visual Aids ▸ Page breaks