[GH-ISSUE #832] Clarifying Lexical Comparison for Identifier Precedence #7518

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GiteaMirror · 2026-06-20T17:35:56-05:00

GiteaMirror commented

2026-06-20 17:35:56 -05:00

Originally created by @Andrei15193 on GitHub (May 5, 2022).
Original GitHub issue: https://github.com/semver/semver/issues/832

Hi,

In the specifications it is mentioned that precedence between identifiers that are not made out of digits (not numbers, basically) is determined by lexical comparison, however I am unsure how this applies to an edge case where one identifier is in the beginning of another identifier. For instance, if I have 1.0.0-alpha and 1.0.0-alpha-prep, which one has precedence? Is it 1.0.0-alpha < 1.0.0-alpha-prep or 1.0.0-alpha-prep < 1.0.0-alpha?

Please include a case like this in the precedence example on the landing page, just for clarification.

Thanks!

Originally created by @Andrei15193 on GitHub (May 5, 2022). Original GitHub issue: https://github.com/semver/semver/issues/832 Hi, In the specifications it is mentioned that precedence between identifiers that are not made out of digits (not numbers, basically) is determined by lexical comparison, however I am unsure how this applies to an edge case where one identifier is in the beginning of another identifier. For instance, if I have `1.0.0-alpha` and `1.0.0-alpha-prep`, which one has precedence? Is it `1.0.0-alpha < 1.0.0-alpha-prep` or `1.0.0-alpha-prep < 1.0.0-alpha`? Please include a case like this in the precedence example on the landing page, just for clarification. Thanks!

GiteaMirror closed this issue

2026-06-20 17:35:56 -05:00

GiteaMirror commented

2026-06-20 17:35:57 -05:00

@jwdonahue commented on GitHub (May 11, 2022):

See 11.4.4:

A larger set of pre-release fields has a higher precedence than a smaller set, if all of the preceding identifiers are equal

@jwdonahue commented on GitHub (May 11, 2022): See [11.4.4](https://semver.org/#spec-item-11): > A larger set of pre-release fields has a higher precedence than a smaller set, if all of the preceding identifiers are equal

GiteaMirror commented

2026-06-20 17:35:57 -05:00

@Andrei15193 commented on GitHub (May 11, 2022):

But in this case the set of pre-release fields is the same size. The pre-release identifiers are alpha and alpha-prep. We can use a different example, 1.0.0-alpha and 1.0.0-alphaPrep, which one has precedence in this case? alpha or alphaPrep?

@Andrei15193 commented on GitHub (May 11, 2022): But in this case the set of pre-release fields is the same size. The pre-release identifiers are `alpha` and `alpha-prep`. We can use a different example, `1.0.0-alpha` and `1.0.0-alphaPrep`, which one has precedence in this case? `alpha` or `alphaPrep`?

GiteaMirror commented

2026-06-20 17:35:58 -05:00

@jwdonahue commented on GitHub (May 11, 2022):

Oh sorry. Alpha-prep is not two fields, my bad. The longer string is greater than the shorter one where they share a common prefix, so -alpha < -alphaPrep.

Standard lexical comparison. The standard libraries or built in string operators of every 3G language applies the same rules. The algorithm is more than a hundred years old.

a < b < ab < c

@jwdonahue commented on GitHub (May 11, 2022): Oh sorry. Alpha-prep is not two fields, my bad. The longer string is greater than the shorter one where they share a common prefix, so -alpha < -alphaPrep. [Standard lexical comparison](https://www.cplusplus.com/reference/algorithm/lexicographical_compare/#:~:text=A%20lexicographical%20comparison%20is%20the,not%20equivalent%20to%20the%20other.). The standard libraries or built in string operators of every 3G language applies the same rules. The algorithm is more than a hundred years old. ----- a < b < ab < c

GiteaMirror commented

2026-06-20 17:35:58 -05:00

@Andrei15193 commented on GitHub (May 11, 2022):

Was guessing that it's like that, but wanted to make sure.

Alright, that clarifies it for me, thank you 😃

@Andrei15193 commented on GitHub (May 11, 2022): Was guessing that it's like that, but wanted to make sure. Alright, that clarifies it for me, thank you 😃

GiteaMirror commented

2026-06-20 17:35:58 -05:00

@jwdonahue commented on GitHub (May 11, 2022):

It gets way more complicated with unicode and semantically equivalent, but different codes. Hence the ASCII restriction.

@jwdonahue commented on GitHub (May 11, 2022): It gets way more complicated with unicode and semantically equivalent, but different codes. Hence the ASCII restriction.

GiteaMirror commented

2026-06-20 17:35:59 -05:00

@jwdonahue commented on GitHub (May 11, 2022):

@Andrei15193 Apologies for the confusion. I must have been more tired last night than I thought. a < b < ab < c is incorrect.

I thought I fixed it, but apparently made the same mistake twice. Good thing I skimmed my emails this morning. I have edited the original, and to be clear it should have been:

a < b < ba < c

Just like in a dictionary.

@jwdonahue commented on GitHub (May 11, 2022): @Andrei15193 Apologies for the confusion. I must have been more tired last night than I thought. `a < b < ab < c` **is incorrect**. I thought I fixed it, but apparently made the same mistake twice. Good thing I skimmed my emails this morning. I have edited the original, and to be clear it should have been: a < b < ba < c Just like in a dictionary.

GiteaMirror commented

2026-06-20 17:35:59 -05:00

@Andrei15193 commented on GitHub (May 11, 2022):

Oh, I totally missed that, I was too focused on the a < ab comparison. Thanks for looking it up! I've edited the comments and removed the quotes.

@Andrei15193 commented on GitHub (May 11, 2022): Oh, I totally missed that, I was too focused on the `a < ab` comparison. Thanks for looking it up! I've edited the comments and removed the quotes.

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Reference: github-starred/semver#7518