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8321139: jlink's man page does not document the --compress option correctly #28359

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8321139: jlink's man page does not document the --compress option correctly #28359

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b1517c3
Update compression level explanation from jlink man page.
ammbra Nov 17, 2025
8749e51
Remove legacy shortcut for --compress.
ammbra Nov 17, 2025
c290e28
Align behavior of compression levels to the input received and sync h…
ammbra Nov 20, 2025
2e6a3f1
Remove extra line.
ammbra Nov 20, 2025
fccce74
Add some negative tests for suggested values.
ammbra Nov 21, 2025
82f4e8d
Refactor variable name.
ammbra Nov 21, 2025
6a21afb
Fix typo in dependencies.
ammbra Nov 21, 2025
d068438
Fix typo in man page too.
ammbra Nov 21, 2025
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21 changes: 14 additions & 7 deletions src/jdk.jlink/share/man/jlink.md
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Expand Up @@ -64,12 +64,15 @@ Developers are responsible for updating their custom runtime images.
`--bind-services`
: Link service provider modules and their dependencies.

`-c ={0|1|2}` or `--compress={0|1|2}`
: Enable compression of resources:
`-c=zip-[0-9]` or `--compress=zip-[0-9]`
: Enable compression of resources. The accepted values are:
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@AlanBateman AlanBateman Nov 17, 2025

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All good for --compress. Can you double check that -c actually works?

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@ammbra ammbra Nov 17, 2025

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Thank you so much for spotting this! -c does not work and jlink --help command does not list it either. Will remove it from this part.

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@AlanBateman AlanBateman Nov 18, 2025 •
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I suspect something has got messed up in the CLI parsing. -c should be the short form of --compress. At this time, -c, with no params, is the equivalent of --compress 2 so we get a confusing warning. As we've found, providing parameters to the short form doesn't seem to work. So I think we need to dig into this more.

Also a comment on the "Deprecated values to be removed in a future release" section. It would be easy to read it that zip-0 and zip-6 are being deprecated. Instead of "Equivalent to zip-0", then maybe we should say "Use zip-0 instead".

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@ammbra ammbra Nov 18, 2025

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So maybe I should investigate first what happened to -c argument and then improve the documentation?

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@AlanBateman AlanBateman Nov 18, 2025

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That would be great, if you have the cycles.

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@ammbra ammbra Nov 20, 2025

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I looked into the issue and provided a fix. Hence I modified the description of this PR and issue related to it. Please let me know if is ok to change the title of the bug and PR as well, to proper reflect the changes introduced. Thank you 🙏 .

zip-[0-9], where zip-0 provides no compression,
and zip-9 provides the best compression. Default is zip-6.

- `0`: No compression
: Deprecated values to be removed in a future release:
- `0`: No compression. Equivalent to zip-0.
- `1`: Constant string sharing
- `2`: ZIP
- `2`: ZIP. Equivalent to zip-6.

`--disable-plugin` *pluginname*
: Disables the specified plug-in. See [jlink Plug-ins] for the list of
Expand Down Expand Up @@ -170,14 +173,18 @@ For a complete list of all available plug-ins, run the command
### Plugin `compress`

Options
: `--compress=`{`0`\|`1`\|`2`}\[`:filter=`*pattern-list*\]
: `--compress=zip-`[`0`-`9`]\[`:filter=`*pattern-list*\]

Description
: Compresses all resources in the output image.
Accepted values are:
zip-[0-9], where zip-0 provides no compression,
and zip-9 provides the best compression. Default is zip-6.

- Level 0: No compression
: Deprecated values to be removed in a future release:
- Level 0: No compression. Equivalent to zip-0.
- Level 1: Constant string sharing
- Level 2: ZIP
- Level 2: ZIP. Equivalent to zip-6.

An optional *pattern-list* filter can be specified to list the pattern of
files to include.
Expand Down