ShareAlike compatibility: GPLv3 - Revision history

CCID-shinchpearson at 21:12, 29 September 2015

2015-09-29T21:12:57Z

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	===License termination===		===License termination===

	Both licenses terminate automatically upon breach. BY-SA is reinstated automatically if the ~~breach~~ is cured within 30 days of discovery. GPLv3 is reinstated for first-time violators who cure within 30 days of ~~getting~~ notice of the violation from the copyright holder, and ~~may be~~ reinstated after ~~other~~ violations if it has been corrected for 60 days without the licensor's objection. ~~These differences make it so one could technically have rights under the GPLv3~~		Both licenses terminate automatically upon breach. BY-SA 4.0 is reinstated automatically if the violation is cured within 30 days of discovery, whether it is the first violation or one of several subsequent violations. GPLv3 is reinstated automatically for first-time violators who cure within 30 days of receiving notice of the violation from the copyright holder, and is reinstated after subsequent violations if it has been corrected for 60 days without the licensor's objection. This difference means that a user of a combined BY-SA adaptation and GPL work may have the right to use some portion but not all portions of the larger work, depending on whether rights have been reinstated under the respective licenses. In practice, however, this difference is not overly problematic and is not be an obstacle to declaring one-way compatibility, since the large majority of licensors and licensees in both communities resolve license violations amicably.
	~~reinstated but not under~~ BY-SA ~~in situations where both licenses apply (i.e. when BY-SA content is adapted~~ and ~~integrated into a~~ GPL~~-licensed project).<ref>[1] Theoretically~~, ~~one could~~ have ~~their rights~~ reinstated under ~~BY-SA but not GPL~~, ~~but~~ this ~~does~~ not ~~create the same risk of potential infringement. Because this~~ is one-way compatibility ~~from BY-SA to GPL only~~, the adapter’s license (i.e. the last-applied license) will always be the GPL. If someone looks only at the GPL when using a GPL project that incorporates a BY-SA work, at worst they will they will not realize they still have rights to the BY-SA work.</ref> As a practical matter, licensors and licensees in both communities ~~typically deal with~~ license violations ~~outside the strict letter of the license, so we feel this is unlikely to be a real world obstacle to compatibility~~.

	===Option to comply with later versions===		===Option to comply with later versions===

CCID-diane peters: /* Considerations for adapters applying the GPLv3 */

2015-09-21T11:34:01Z

Considerations for adapters applying the GPLv3

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	==Considerations for adapters applying the GPLv3==		==Considerations for adapters applying the GPLv3==
	~~Both because~~ of the limited one-way nature of compatibility and because GPLv3 is designed for software, there are a few particular considerations to take into account before applying the GPLv3 as the adapter’s license when adapting BY-SA works.		Because of the limited one-way nature of this compatibility determination and because GPLv3 is designed for software, there are a few particular considerations to take into account before applying the GPLv3 as the adapter’s license when adapting BY-SA 4.0 works.

	:*'''This one-way compatibility mechanism with GPLv3 is not for general use.''' It was designed to help solve a specific problem for those working in niche areas where content is melded with code. Please take advantage of it only when you are adapting BY-SA works into GPLv3 software in ways that make it difficult or impossible for downstream users to distinguish the content from code.		:*'''This one-way compatibility mechanism with GPLv3 is not for general use.''' It was designed to help solve a specific problem for those working in niche areas where content is adapted and melded with code. Please take advantage of it only when you are adapting BY-SA 4.0 works and incorporating the adaptation into GPLv3 software in ways that make it difficult or impossible for downstream users to distinguish the content from code.

	:* '''BY-SA does not include a patent license.''' ~~Do not apply the~~ GPLv3 if you have any reason to suspect that any patent rights held by the original BY-SA licensor could pose a problem for downstream users.		:* '''BY-SA does not include a patent license.''' We recommend against applying GPLv3 if you have any reason to suspect that any patent rights held by the original BY-SA 4.0 licensor could pose a problem for downstream users.

	:* '''BY-SA works may not be available in the preferred form for making modifications.''' Do not apply the GPLv3 if you cannot comply with the source requirement in the GPL.		:* '''BY-SA 4.0 works may not be available in the preferred form for making modifications.''' Do not apply the GPLv3 if you cannot comply with the source requirement in the GPL.

	:* '''This compatibility determination only applies to ~~GPL version 3~~.''' You must specify version 3 of the GPL when redistributing a GPL project into which BY-SA content is adapted. Please see [[ShareAlike_compatibility:_GPLv3#Option_to_comply_with_later_versions\|above]] for information on how to deal with this if you are particularly concerned with enabling compatibility with future versions of the GPL.		:* '''This compatibility determination only applies to BY-SA 4.0 and GPLv3.''' You must specify version 3 of the GPL when redistributing a GPL project into which BY-SA 4.0 content is adapted. Please see [[ShareAlike_compatibility:_GPLv3#Option_to_comply_with_later_versions\|above]] for information on how to deal with this if you are particularly concerned with enabling compatibility with future versions of the GPL.

	== Notes ==		== Notes ==
	<references />		<references />

CCID-diane peters: /* Related policy notes */

2015-09-21T11:30:45Z

Related policy notes

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	==Related policy notes==		==Related policy notes==
	Creative Commons consulted extensively with the ~~steward of the GPL v.3~~ during the 4.0 versioning process, as well as throughout the compatibility process on the policy matters described above. The final determination and policy statements above reflect the best interpretations by both stewards of their respective licenses.		Creative Commons consulted extensively with the Free Software Foundation during the 4.0 versioning process, as well as throughout the compatibility process on the policy matters described above. The final determination and policy statements above reflect the best interpretations by both stewards of their respective licenses.

	==Considerations for adapters applying the GPLv3==		==Considerations for adapters applying the GPLv3==

CCID-diane peters: /* Option to comply with later versions */

2015-09-21T11:30:04Z

Option to comply with later versions

← Older revision		Revision as of 11:30, 21 September 2015
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	===Option to comply with later versions===		===Option to comply with later versions===

	GPLv3 gives licensees the option to comply with a later version of the GPL if the licensor has so specified, or to use any version of the GPL if no version number was specified, regardless of whether the work has been adapted. BY-SA allows licensees to comply with the conditions of future versions of BY-SA, but only if that version was applied to an adaptation of the work. Because ~~only~~ version 3 of the GPL ~~is an option for compatibility at this time~~, reusers that adapt BY-SA content into GPL-licensed projects are only able to use GPLv3 unless and until other GPL versions are ~~made~~ compatible. With solid education for both communities and encouragement of clear marking by licensors, we do not feel this is an obstacle to compatibility.		GPLv3 gives licensees the option to comply with a later version of the GPL if the licensor has so specified, or to use any version of the GPL if no version number was specified, regardless of whether the work has been adapted. BY-SA 4.0 allows licensees to comply with the conditions of future versions of BY-SA, but only if that version was applied to an adaptation of the work. Because this compatibility determination is limited to version 3 of the GPL, reusers that adapt BY-SA 4.0 content and incorporate it into GPL-licensed projects are only able to use GPLv3 unless and until other GPL versions are declared compatible. With solid education for both communities and encouragement of clear marking by licensors, we do not feel this is an obstacle to compatibility.

	~~Also, those~~ GPL licensors who are concerned with enabling use under later versions do have the option of using the proxy provision in the GPLv3 ~~for~~ this. Section 14 of ~~the~~ GPLv3 allows licensors to specify a proxy to determine whether future versions of the GPL can be used. Therefore, if someone adapts a BY-SA 4.0 work into a GPLv3 project, they can specify Creative Commons as their proxy (via http://creativecommons.org/compatiblelicenses) so that if and when Creative Commons determines that a future version of the GPL is a compatible license, the adapted work could be used under that later version.		GPL licensors who are concerned with enabling use under later versions do have the option of using the proxy provision in the GPLv3 to address this limitation. Section 14 of GPLv3 allows licensors to specify a proxy to determine whether future versions of the GPL can be used. Therefore, if someone adapts a BY-SA 4.0 work and incorporates it into a GPLv3-licensed project, they can specify Creative Commons as their proxy (via http://creativecommons.org/compatiblelicenses) so that if and when Creative Commons determines that a future version of the GPL is a compatible license, the adapted and combined work could be used under that later version of GPL.

	==Related policy notes==		==Related policy notes==

CCID-diane peters: /* Effective technological measures */

2015-09-21T11:08:39Z

Effective technological measures

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	BY-SA prohibits application of ETMs by licensees if those measures would prevent others from exercising their rights under the license. In contrast, the GPL does not explicitly prohibit application of DRM and other ETMs. Instead, it addresses any potential lockdown of licensed works by requiring distribution of source code in a modifiable form.		BY-SA prohibits application of ETMs by licensees if those measures would prevent others from exercising their rights under the license. In contrast, the GPL does not explicitly prohibit application of DRM and other ETMs. Instead, it addresses any potential lockdown of licensed works by requiring distribution of source code in a modifiable form.

	This difference is not problematic, because in order to comply with GPLv3 the adapter must provide source. As stated in the previous section, if an adapter cannot provide or make source available, she cannot use GPLv3 for her contributions.		This difference is not problematic, because in order to comply with GPLv3 the adapter must provide source. As stated in the previous section, if an adapter cannot provide or make source available, she cannot take advantage of the one-way compatibility declaration and may not use GPLv3 for her contributions.

	===License termination===		===License termination===

CCID-diane peters at 11:07, 21 September 2015

2015-09-21T11:07:57Z

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	This creates the possibility that a downstream user of a GPL project will mistakenly assume that all patent rights are treated as they are in GPLv3 when in fact they are not. We have determined, however, that this should not prevent a determination of one-way compatibility because it is largely an academic problem. Rarely (if ever) would a BY-SA work be subject to patent rights that would be implicated by reproducing or adapting the content.		This creates the possibility that a downstream user of a GPL project will mistakenly assume that all patent rights are treated as they are in GPLv3 when in fact they are not. We have determined, however, that this should not prevent a determination of one-way compatibility because it is largely an academic problem. Rarely (if ever) would a BY-SA work be subject to patent rights that would be implicated by reproducing or adapting the content.

	===~~Effective technological measures~~===		===Source===

	BY-SA ~~prohibits application of ETMs by licensees entirely if those measures would prevent others from exercising their rights under the license. In contrast, the GPL~~ does not ~~explicitly prohibit application of DRM and other ETMs~~. Instead, ~~it addresses any potential lockdown of licensed~~ works ~~by requiring distribution of source code~~ in a modifiable ~~form~~.		The GPL requires that works be distributed with source or that source be made available (with “source” being the preferred form for making modifications to the work). BY-SA does not impose a similar requirement. Instead, BY-SA licensors are free to distribute their works in any format, whether or not modifiable.

	~~This creates a risk that~~ BY-SA ~~works adapted into GPL-licensed projects could be subject to DRM applied by~~ downstream ~~users~~ who ~~look only at~~ the GPL ~~requirements~~. However, ~~we feel this risk is adequately neutralized by~~ the GPL ~~requirement~~ to provide source.		With one-way compatibility to the GPL, no new obligations are imposed under the BY-SA license, either upon the original licensor or any downstream adapter who wishes to license their contributions under the GPL instead of BY-SA. However, those who adapt BY-SA works and choose to license their contributions under the GPL do, however, have to comply with the GPL obligation to distribute or make available the work in the preferred form for making modifications. If an adapter cannot provide or make available source either because she never received the work in modifiable format from the BY-SA licensor or cannot convert the content to modifiable format, then that person cannot take advantage of the one-way compatibility declaration and use the GPLv3 for her contributions.

	===~~Source~~===		===Effective technological measures===

	~~The GPL requires that works be distributed with source or that source be made available (with “source” being the preferred form for making modifications to the work).~~ BY-SA does not ~~impose a similar requirement~~. Instead, ~~BY-SA licensors are free to distribute their~~ works in ~~any format, whether or not~~ modifiable.		BY-SA prohibits application of ETMs by licensees if those measures would prevent others from exercising their rights under the license. In contrast, the GPL does not explicitly prohibit application of DRM and other ETMs. Instead, it addresses any potential lockdown of licensed works by requiring distribution of source code in a modifiable form.

	~~With one-way compatibility~~ to the ~~GPL, no new obligations are imposed under the BY-SA license, either upon the original licensor or any downstream~~ adapter ~~who wishes to license their contributions under the GPL instead of BY-SA~~. ~~However, those who adapt BY-SA works and choose to license their contributions under~~ the ~~GPL do~~, ~~however, still have to comply with the GPL obligation to distribute~~ or make available ~~the work in the preferred form for making modifications. If a particular adapter cannot do this because~~ she ~~never received modifiable format from the BY-SA licensor and/or~~ cannot ~~convert the content to modifiable format, then that person may not take advantage of the one-way compatibility declaration and~~ use ~~the GPL~~.		This difference is not problematic, because in order to comply with GPLv3 the adapter must provide source. As stated in the previous section, if an adapter cannot provide or make source available, she cannot use GPLv3 for her contributions.

	===License termination===		===License termination===

CCID-diane peters: /* License scope */

2015-09-21T10:58:02Z

License scope

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	The most significant difference in license scope is the treatment of patent rights. BY-SA expressly reserves patent rights to the licensor, while GPLv3 expressly includes a patent grant from each contributor.		The most significant difference in license scope is the treatment of patent rights. BY-SA expressly reserves patent rights to the licensor, while GPLv3 expressly includes a patent grant from each contributor.

	Because patent rights are expressly excluded from BY-SA, there is no reliable claim of an implied license to do things with a BY-SA licensed work that implicate patent rights. From a compatibility perspective, this means that when a BY-SA work is adapted ~~into~~ a GPL-licensed project, downstream users of the project would not have patent rights to the BY-SA work.		Because patent rights are expressly excluded from BY-SA, there is no reliable claim of an implied license to do things with a BY-SA licensed work that implicate patent rights. From a compatibility perspective, this means that when a BY-SA work is adapted and included in a GPL-licensed project, downstream users of the project would not have patent rights (if any) to the adapted BY-SA work.
	(Although the GPL includes a patent license, the scope of rights licensed by the BY-SA licensor cannot be expanded ~~because~~ an adapter ~~applies~~ the GPL, just as it is not expanded when an adapter applies a later version of BY-SA that licenses more rights than the original.)		(Although the GPL includes a patent license, the scope of rights licensed by the BY-SA licensor cannot be unilaterally expanded by an adapter who choses to apply the GPL, just as it is not expanded when an adapter applies a later version of BY-SA that licenses more rights than the original.)

	This creates the possibility that a downstream user of a GPL project will mistakenly assume that they do not have ~~to consider patent rights even though a BY-SA work is adapted into the project. However~~, ~~we do not feel~~ this is should prevent one-way compatibility because it is largely an academic problem~~, given how rarely~~ BY-SA ~~works are~~ subject to ~~patents~~ that would be implicated by ~~simply~~ reproducing or adapting the content.		This creates the possibility that a downstream user of a GPL project will mistakenly assume that all patent rights are treated as they are in GPLv3 when in fact they are not. We have determined, however, that this should not prevent a determination of one-way compatibility because it is largely an academic problem. Rarely (if ever) would a BY-SA work be subject to patent rights that would be implicated by reproducing or adapting the content.

	===Effective technological measures===		===Effective technological measures===

CCID-diane peters: /* Attribution */

2015-09-21T10:53:32Z

Attribution

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	The specific attribution and marking requirements in the two licenses vary slightly.		The specific attribution and marking requirements in the two licenses vary slightly.

	BY-SA requires:		BY-SA 4.0 requires:
	#creator and attribution parties (if supplied)		#creator and attribution parties (if supplied)
	# copyright notice (if supplied)		# copyright notice (if supplied)
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	#indicate and link to license		#indicate and link to license

	If you change the work, BY-SA also requires you to indicate that you did so and retain any notice on the work about previous changes made to it. BY-SA requires reusers to remove attribution when requested by the licensor.		If you change the work, BY-SA also requires you to indicate that you did so and retain any notice on the work about previous changes made to it. BY-SA requires reusers to remove attribution if practicable when requested by the licensor.

	~~GPL~~ requires:		GPLv3 requires:
	#copyright notice		#copyright notice
	#license notices and notice of [http://www.gnu.org/licenses/gpl-3.0.html#section7 Section 7 additional conditions] (if supplied)		#license notices and notice of [http://www.gnu.org/licenses/gpl-3.0.html#section7 Section 7 additional conditions] (if supplied)
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	If you change the work, GPL requires you include a prominent notice to indicate that you did so, along with the relevant date. It also requires special notices for certain interactive user interfaces. GPLv3 does not have an attribution removal clause.		If you change the work, GPL requires you include a prominent notice to indicate that you did so, along with the relevant date. It also requires special notices for certain interactive user interfaces. GPLv3 does not have an attribution removal clause.

	When BY-SA content is adapted ~~into~~ a ~~GPL~~-licensed project, the adapter has to comply with the BY-SA attribution and marking requirements. However, Section 2(a)(5)(B) of BY-SA 4.0 enables downstream reusers of the GPL-licensed project to look to the GPL to satisfy their obligations to both ~~authors~~. CC determined that GPL-style attribution would satisfy the expectations of BY-SA licensors.		When BY-SA 4.0 content is adapted and used in a GPLv3-licensed project, the adapter has to comply with the BY-SA attribution and marking requirements. However, Section 2(a)(5)(B) of BY-SA 4.0 enables downstream reusers of the GPL-licensed project to look to the GPL to satisfy their obligations under both licenses. CC determined that GPL-style attribution would satisfy the expectations of BY-SA licensors.

	===License scope===		===License scope===

CCID-diane peters: /* How one-compatibility operates */

2015-09-21T10:51:19Z

How one-compatibility operates

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	==How one-compatibility operates==		==How one-compatibility operates==

	When someone ~~adapts~~ a BY-SA work ~~into~~ a GPLv3 project, both licenses apply and downstream users must comply with both. However, ~~because of~~ [https://creativecommons.org/licenses/by-sa/4.0/legalcode#s2a5B Section 2(a)(5)(B)] of BY-SA 4.0, anyone who receives the adapted material downstream ~~may~~ satisfy the conditions of both BY-SA and GPLv3 (i.e. attribution and ShareAlike) in the manner dictated by the GPLv3.		When someone creates an adaptation of a BY-SA licensed work and includes it in a GPLv3-licensed project, both licenses apply and downstream users must comply with both licenses. However, [https://creativecommons.org/licenses/by-sa/4.0/legalcode#s2a5B Section 2(a)(5)(B)] of BY-SA 4.0 allows anyone who receives the adapted material downstream to satisfy the conditions of both BY-SA and GPLv3 (i.e. attribution and ShareAlike) in the manner dictated by the GPLv3.

	People may not ~~take~~ GPLv3 work and ~~apply~~ BY-SA to their contributions. This compatibility determination only allows movement one way, from BY-SA to ~~GPL~~.		People may not adapt a GPLv3-licensed work and use BY-SA to license their contributions. This is not allowed by GPLv3. Thus, this compatibility determination only allows movement one way, from BY-SA 4.0 to GPLv3.

	For more information, see the compatibility-specific FAQs and explanatory information [https://wiki.creativecommons.org/ShareAlike_compatibility here]. We also encourage you to read this list of [[ShareAlike_compatibility:_GPLv3#Considerations_for_adapters_applying_the_GPLv3\|considerations before applying the GPLv3]] as the adapter’s license.		For more information, see the compatibility-specific FAQs and explanatory information [https://wiki.creativecommons.org/ShareAlike_compatibility here]. We also encourage you to read this list of [[ShareAlike_compatibility:_GPLv3#Considerations_for_adapters_applying_the_GPLv3\|considerations before applying the GPLv3]] as the adapter’s license.

	==Gatekeeping determination==		==Gatekeeping determination==

CCID-diane peters: /* Timeline */

2015-09-21T10:47:21Z

Timeline

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	*CC published a [[ShareAlike_compatibility_analysis:_GPL\|preliminary analysis]] of compatibility with GPL on its wiki.		*CC published a [[ShareAlike_compatibility_analysis:_GPL\|preliminary analysis]] of compatibility with GPL on its wiki.
	*Public discussion period ran from 29 January to [http://lists.ibiblio.org/pipermail/cc-licenses/2015-April/007691.html 2 April 2015].		*Public discussion period ran from 29 January to [http://lists.ibiblio.org/pipermail/cc-licenses/2015-April/007691.html 2 April 2015].
	*Compatibility determination published on __ ~~May~~ 2015 and GPLv3 added to [https://creativecommons.org/compatiblelicenses the CC compatible license page]		*Compatibility determination published on __ September 2015 and GPLv3 added to [https://creativecommons.org/compatiblelicenses the CC compatible license page]

	==License texts analyzed==		==License texts analyzed==