[Fix] nvm_strip_path: Preserve leading/trailing colons
#3145
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Path lists in environmental variables often give special meaning to empty entries (e.g. in PATH or MANPATH). These are represented by leading or trailing colons, or by doubled colons in the middle of the list. Adjust the awk invocation to correctly deal with trailing colons by printing the separator before every field except the first, and then printing the final separator that is read from the input - this will either be a colon or the null string. This preserves leading and trailing colons in all cases while not adding extra colons in the wrong place. Add test to confirm the correct behaviour. Fixes nvm-sh#3144
As noted in the bug, empty directory names in PATH do have some meaning, even if it seems less useful. So colons should be preserved there too.
I think the existing tests already cover this case anyway, they have entries in $NVM_DIR at the end of $TEST_PATH. |
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The other potential problem case is when it's not at the beginning or end. |
This works fine I think - with the patch I get: because awk continues to the next record when it finds a path entry to remove, and skips the part that prints anything. Note that when the MANPATH or PATH documentation talks about a trailing colon, they mean when a colon is the last character in the input env variable, not about every colon used as a record separator. I feel like there's a bit of subtlety here, and half the challenge is to explain it well in the commit log. |
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Hmm, it's also possible that I'm stuck on my mental model from the original implementation, which did not use awk - maybe the awk-based solution doesn't have this fragility. |
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nvm_strip_path: Preserve leading/trailing colons
Preserve leading & trailing colons in awk invocation.