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your system with newer versions. As long as packages are always perfectly backward-compatible, this is not a problem, but in the real world, packages are anything but perfectly backward-compatible. Suppose you upgrade
Firefox, and your package manager decides that you need a newer version of GTK as well. If the new GTK is not quite backward-compatible, then other applications on your system might suddenly break. In the Windows world a similar problem is known as the DLL hell, but dependency hell is just as much a problem in the Unix world, if not a bigger one, because Unix programs tend to have many external dependencies.
293:, then upgrading any application will break another. This scheme can be deeper in branching. Its impact can be quite heavy if it affects core systems or update software itself: a package manager (A), which requires specific run-time library (B) to function, may break itself (A) in the middle of the process when upgrading this library (B) to next version. Due to incorrect library (B) version, the package manager (A) is now broken, thus no rollback or downgrade of library (B) is possible. The usual solution is to download and deploy both applications, sometimes from within a temporary environment.
22:
167:, requiring lengthy downloads, large amounts of disk space, and being very portable (all libraries are already ported enabling the application itself to be ported easily). It can also be difficult to locate all the dependencies, which can be fixed by having a repository (see below). This is partly inevitable; an application built on a given
547:
or component library designers and quickly adjust their software with updates for their users, all with minimal effort and a lack of costly and time-consuming redesign. This method would encourage programmers to pressure those upon whom they depend to maintain a reasonable notification process that is not onerous to anyone involved.
383:. The major version only changes when programs that used that version will no longer be compatible. The minor version might change with even a simple revision that does not prevent other software from working with it. In cases like this, software packages can then simply request a component that has a particular major version, and
147:
packages or libraries, but they depend on different and incompatible versions of the shared packages. If the shared package or library can only be installed in a single version, the user may need to address the problem by obtaining newer or older versions of the dependent packages. This, in turn, may
546:
If application software is designed in such a way that its programmers are able to easily adapt the interface layer that deals with the OS, window manager or desktop environment to new or changing standards, then the programmers would only have to monitor notifications from the environment creators
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cannot simultaneously be used (or installed, if the installer checks dependencies). When possible, this is solved by allowing simultaneous installations of the different dependencies. Alternatively, the existing dependency, along with all software that depends on it, must be uninstalled in order to
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version number constraints, effectively transferring the responsibility for brokering library/module versions from the applications to the operating system. A shared module can then be placed in a central repository without the risk of breaking applications which are dependent on previous or later
354:
Many software libraries are written in a generous way, in an attempt to fulfill most users' needs, but sometimes only a small portion of functions are required in the host code. By examining the source, the functionality can be rewritten in a much more compact way (with respect to the license). In
898:
All popular package managers, including APT, RPM and the FreeBSD Ports
Collection, suffer from the problem of destructive upgrades. When you perform an upgrade -- whether for a single application or your entire operating system -- the package manager will overwrite the files that are currently on
553:
If the applications and libraries are developed and maintained with guaranteed downward compatibility in mind, any application or library can be replaced with a newer version at any time without breaking anything. While this does not alleviate the multitude of dependency, it does make the jobs of
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minor version (greater than or equal to a particular minor version). As such, they will continue to work, and dependencies will be resolved successfully, even if the minor version changes. Semantic
Versioning (aka "SemVer") is one example of an effort to generate a technical specification that
582:
An application (or version of an existing conventional application) that is completely self-contained and requires nothing to be already installed. It is coded to have all necessary components included, or is designed to keep all necessary files within its own directory, and will not create a
401:
prevented applications from overwriting system DLLs. Developers were instead encouraged to use "Private DLLs", copies of libraries per application in the directory of the application. This uses the
Windows search path characteristic that the local path is always prioritized before the system
221:
below). These long chains of dependencies can be solved by having a package manager that resolves all dependencies automatically. Other than being a hassle (to resolve all the dependencies manually), manual resolution can mask dependency cycles or
566:. A software appliance encapsulates dependencies in a pre-integrated self-contained unit such that users no longer have to worry about resolving software dependencies. Instead the burden is shifted to developers of the software appliance.
261:
install the new dependency. A problem on Linux systems with installing packages from a different distributor (which is not recommended) is that the resulting long chain of dependencies may lead to a conflicting version of the
512:
or, much less commonly, directories on removable media such as CDs or DVDs. This eliminates dependency hell for software packaged in those repositories, which are typically maintained by the Linux distribution provider and
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worldwide. Although these repositories are often huge, it is not possible to have every piece of software in them, so dependency hell can still occur. In all cases, dependency hell is still faced by the repository
325:
When a library A depends on libraries B and C, both B and C depend on library D, but B requires version D.1 and C requires version D.2. The build fails because only one version of D can exist in the final
618:
toolkit, which these programs use to render widgets. On the other hand, if different versions of GTK are required by each application, then this is the correct behavior and successfully avoids dependency
423:
The version numbering solution can be improved upon by elevating the version numbering to an operating system supported feature. This allows an application to request a module/library by a unique name
598:
This method of distribution has also proven useful when porting applications designed for Unix-like platforms to
Windows, the most noticeable drawback being multiple installations of the same
175:) requires that platform to be installed, but further applications do not require it. This is a particular problem if an application uses a small part of a big library (which can be solved by
402:
directory with the system wide libraries. This allows easy and effective shadowing of library versions by specific application ones, therefore preventing dependency hell.
453:
can perform smart upgrades, in which interdependent software components are upgraded at the same time, thereby resolving the major number incompatibility issue too.
912:
217:, and so on. Sometimes, however, during this long chain of dependencies, conflicts arise where two different versions of the same package are required (see
303:), but this is unlikely since major package managers have matured and official repositories are well maintained. This is the case with current releases of
804:
355:
general, this can reduce significantly the application code and, later, the maintenance costs, and programmers can improve their software writing skills.
363:
A very common solution to this problem is to have a standardized numbering system, wherein software uses a specific number for each version (aka
1090:
417:, which avoids breakage if system libraries are upgraded or changed. It uses its own "PBI" (Push Button Installer) for package management.
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836:
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can resolve this by presenting the user with a range of solutions, and allowing the user to accept or reject the solutions, as desired.
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is an implementation of such a central registry with associated services and integrated with the installation system/package manager.
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105:
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are prone to have conflicts between packages of their repositories, causing dependency hell in Linux distributions such as
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201:. This is distinct from "many dependencies" if the dependencies must be resolved manually, e.g., on attempting to install
595:, which work in much the same way: programs and their dependencies are self-contained in their own directories (folders).
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dependency problem. These are often able to run independently of the system to which they are connected. Applications in
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881:
443:
solves this problem with a concept called slotting, which allows multiple versions of shared libraries to be installed.
65:
269:), on which thousands of packages depend. If this happens, the user will be prompted to uninstall all those packages.
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464:-based package management systems to try to solve the dependency problem. These systems are a layer on top of the
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472:, or other packaging systems that are designed to automatically resolve dependencies by searching in predefined
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versions of the module. Each version gets its own entry, side by side with other versions of the same module.
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It is possible for dependency hell to result from installing a prepared package via a package manager (e.g.
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Solving the dependencies for one software may break the compatibility of another in a similar fashion to
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311:. Dependency hell, however, can result from installing a package directly via a package installer (e.g.
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of requirements, as each new package demands several more be installed. Systems such as Debian's
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Because different pieces of software have different dependencies, it is possible to get into a
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632:, "dependency hell" often goes by a local specific name, generally the name of components.
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The dependency issue arises when several packages have dependencies on the same
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a literary depiction of situations where something depends on its own negation
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Another approach to avoiding dependency issues is to deploy applications as a
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employs specifically formatted numbers to create a software versioning scheme.
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break other dependencies and push the problem to another set of packages.
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and Docker Hub) can be seen as an implementation of software appliances.
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410:
701: – techniques and tools for managing software versions
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RPM hell – a form of dependency hell occurring in the
413:) places packages and dependencies into self-contained directories in
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406:
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304:
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Strict compatibility requirement in code development and maintenance
289:, in turn, depends upon and can't run without a specific version of
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Colloquial term for software requiring many conflicting dependencies
1050:
675:
603:
485:
457:
639: – a form of dependency hell occurring on 16-bit
607:
489:
469:
316:
707: – forms of dependency among software artifacts
837:"It's Good Work When You Can Find It; The Dependency Carousel"
659: – a form of dependency hell occurring in the
649: – a form of dependency hell occurring on the
615:
128:
for the frustration of some software users who have installed
15:
880:
Pjotr Prins; Jeeva Suresh & Eelco
Dolstra (2008-12-22).
405:
PC-BSD, up to and including version 8.2, a predecessor of
281:
depends upon and can't run without a specific version of
882:"Nix fixes dependency hell on all Linux distributions"
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and others. Typically, the software repositories are
179:), or a simple application relies on many libraries.
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46:. Unsourced material may be challenged and removed.
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435:operating systems since Windows Vista, where the
369:), and also a subnumber for each revision (aka
420:Side-by-side installation of multiple versions
8:
570:and their images (such as those provided by
554:package managers or installers much easier.
805:"Improved Portability of Shared Libraries"
508:on the local computer or shared across a
252:cannot be simultaneously installed, then
106:Learn how and when to remove this message
756:
213:, the user is then prompted to install
810:. Princeton University. Archived from
602:. For example, Windows installers for
156:Dependency hell takes several forms:
7:
847:(5). www.drdobbs.com/blog: 121–124.
614:all include identical copies of the
476:. Examples of these systems include
460:distributions have also implemented
44:adding citations to reliable sources
209:first and on attempting to install
205:, the user is prompted to install
14:
678:and other distributions that use
543:Easy adaptability in programming
391:Private per application versions
20:
955:. microsoft.com. Archived from
163:An application depends on many
31:needs additional citations for
1021:Weinstein, Paul (2003-09-11).
409:(an operating system based on
307:and major derivatives such as
1:
1091:Software engineering folklore
951:Anderson, Rick (2000-01-11).
938:"Project website: semver.org"
711:Dynamic dead code elimination
803:Donald, James (2003-01-25).
667:solved this problem in 2004.
296:Package manager dependencies
248:, and different versions of
140:of other software packages.
884:. linux.com. Archived from
182:Long chains of dependencies
1107:
1076:Package management systems
835:Stevens, Al (2001-05-01).
772:. O'Reilly Media. p.
768:Linux annoyances for geeks
1001:"Application directories"
431:This solution is used in
699:Configuration management
663:before build tools like
661:Java Runtime Environment
446:Smart package management
339:Red Hat Enterprise Linux
225:Conflicting dependencies
219:conflicting dependencies
197:, ..., which depends on
1081:Version control systems
593:application directories
538:Advanced Packaging Tool
532:, or an ever-expanding
395:Windows File Protection
329:Package managers like
953:"The End of DLL Hell"
913:"Yum Dependency Hell"
764:Michael Jang (2006).
682:as a package manager.
578:Portable applications
474:software repositories
437:Global Assembly Cache
351:Removing dependencies
273:Circular dependencies
1046:Context independence
1025:. linuxdevcenter.com
1023:"Is Linux Annoying?"
40:improve this article
1056:Implicit dependency
741:Nix package manager
736:Supply chain attack
630:computing platforms
558:Software appliances
504:sites or websites,
193:, which depends on
726:Software appliance
647:Extension conflict
564:software appliance
322:Diamond dependency
263:C standard library
169:computing platform
1051:Dependency walker
641:Microsoft Windows
624:Platform-specific
521:Installer options
433:Microsoft Windows
360:Version numbering
160:Many dependencies
130:software packages
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55:"Dependency hell"
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57: –
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51:Find sources:
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35:
34:
29:This article
27:
23:
18:
17:
1027:. Retrieved
1016:
1004:. Retrieved
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983:
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961:. Retrieved
957:the original
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932:
921:. Retrieved
917:the original
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890:. Retrieved
886:the original
861:. Retrieved
857:the original
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840:
830:
819:. Retrieved
812:the original
798:
787:. Retrieved
767:
759:
665:Apache Maven
628:On specific
627:
530:requirements
518:maintainers.
441:Gentoo Linux
424:
414:
399:Windows 2000
384:
380:
376:
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364:
230:whack-a-mole
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136:on specific
134:dependencies
121:
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69:
62:
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38:Please help
33:verification
30:
1006:7 September
589:ROX Desktop
506:directories
326:executable.
244:depends on
236:depends on
189:depends on
132:which have
96:August 2024
1070:Categories
1029:2010-04-10
963:2010-07-07
923:2015-12-28
892:2013-05-22
863:2010-04-10
821:2010-04-09
789:2012-02-16
752:References
568:Containers
462:repository
265:(e.g. the
246:libfoo 1.3
238:libfoo 1.2
222:conflicts.
66:newspapers
853:1044-789X
415:/Programs
379:.1, or 5.
375:), e.g.:
346:Solutions
171:(such as
165:libraries
988:Slotting
746:Left-pad
705:Coupling
693:Catch-22
687:See also
657:JAR hell
637:DLL Hell
587:and the
515:mirrored
152:Problems
138:versions
672:Red Hat
612:HexChat
585:RISC OS
510:network
494:Portage
411:FreeBSD
80:scholar
977:pbiDIR
851:
780:
610:, and
572:Docker
498:Pacman
407:TrueOS
335:CentOS
309:Ubuntu
305:Debian
285:, but
250:libfoo
240:, and
145:shared
82:
75:
68:
61:
53:
841:J-DDJ
815:(PDF)
808:(PDF)
676:Linux
619:hell.
604:gedit
486:Urpmi
458:Linux
449:Some
232:. If
124:is a
87:JSTOR
73:books
1008:2013
849:ISSN
778:ISBN
608:GIMP
534:tree
490:ZYpp
470:dpkg
337:and
317:dpkg
258:app2
256:and
254:app1
242:app2
234:app1
215:libb
211:liba
207:liba
199:libz
195:libb
191:liba
173:Java
59:news
774:325
721:PBI
680:RPM
616:GTK
502:FTP
482:Yum
478:Apt
466:RPM
425:and
385:any
331:yum
315:or
313:RPM
301:APT
277:If
203:app
187:app
185:If
42:by
1072::
895:.
872:^
845:26
843:.
839:.
776:.
606:,
496:,
492:,
488:,
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377:10
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653:.
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381:7
341:.
109:)
103:(
98:)
94:(
84:·
77:·
70:·
63:·
36:.
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